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ASDL disseminates knowledge to the industry through conferences and publications. ASDL Research Engineers and graduate students present their research at a number of conferences through the year. More than 600 ASDL papers have been presented at conferences in the last 20 years. In addition, ASDL publishes more extensive research in peer-reviewed journals, with 160 journal papers being published in the last two decades.
Click here to access ASDL publications on Georgia Tech's online repository SMARTech.
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Abel, R.W., Schrage, D.P. & Mavris, D.N. Preliminary design of the High Speed Civil Transport based on productivity index
[Abstract] [BibTeX]
Vol. 1(A94-31534 10-01)ICAS, Congress, 19th, Anaheim, CA, Proceedings; UNITED STATES; 18-23 Sept. 1994, pp. 378-387 conference
Abstract: Recent industry and NASA research suggests that improved technology could make the next generation High Speed Civil Transport (HSCT) economically and environmentally successful. The focus of the study presented in this paper was to investigate the effect of multidisciplinary design changes on the criterion function-productivity index of the HSCT aircraft. Manufacturing costs were also investigated. (Author)
@conference{Abel1994,
author = {Reginald W. Abel and Daniel P. Schrage and Dimitri N. Mavris},
title = {Preliminary design of the High Speed Civil Transport based on productivity index},
booktitle = {ICAS, Congress, 19th, Anaheim, CA, Proceedings; UNITED STATES; 18-23 Sept. 1994},
publisher = {Washington, DC: American Inst. of Aeronautics and Astronautics, Inc.},
number = {A94-31534 10-01},
note = {Database Name: Aerospace & High Technology Database.
Conference: ICAS, Congress, 19th, Anaheim, CA, Proceedings. Vol. 1; UNITED STATES; 18-23 Sept. 1994.
Other Numbers: A94-31534 10-01.
Notes: Proceedings. Vol. 1 (A94-31534 10-01).
Publication Type: Conference Paper.
Classification: 11 Aircraft (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Update: 199400.
Accession Number: 2001-11-021898 (MT); A94-31574 (AH).
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH).}
Ahn, B.-H., DeLaurentis, D. & Mavris, D.N. Advanced personal air vehicle concept development using powered rotor and autogyro configurations
2002 2002 AIAA Aircraft Technology, Integration, and Operations (ATIO) Forum, Los Angeles, CA; UNITED STATES; 1-3 Oct. 2002 inproceedings
Abstract: The purpose of the study reported in this paper is to develop advanced rotorcraft concepts and identify critical technologies that enable a near-door-to-door, airborne, personal transportation capability. Specifically, the goal of the concept development and subsequent sensitivity analysis is to identify powered rotor and autogyro concepts capable of satisfying these basic Personal Air Vehicle requirements. The concept development study is centered upon two main thrusts. The first is the development of baseline vehicle concepts in two areas (helicopter, autogyro) sized for each of four specified missions, incorporating state-of-art technologies. The second is the development of advanced technology versions of these baselines in order to fulfill the unmet portions of the specified mission matrix and identify required critical technologies. These two vehicle development efforts were accomplished using a calibrated in-house mission sizing and performance program for rotorcraft. Recent upgrades to the program for the capability of modeling the autogyro configuration are also described. To examine sensitivities of the vehicle concepts developed, an advanced system design methodology was applied, utilizing the vehicle synthesis code for evaluation of generic technology areas. Some tools that are part of the methodology can assist in the performance of several of the subtasks in the present study, including mission sensitivity calculation /interpretation and technology identification/evaluation. Further, an approach called the Unified Tradeoff Environment to examine the tradeoffs between mission requirements and the level of technologies needed was employed. (Author)
@inproceedings{Ahn2002,
author = {Byung-Ho Ahn and Daniel DeLaurentis and Dimitri N. Mavris},
title = {Advanced personal air vehicle concept development using powered rotor and autogyro configurations},
booktitle = {2002 AIAA Aircraft Technology, Integration, and Operations (ATIO) Forum, Los Angeles, CA; UNITED STATES; 1-3 Oct. 2002},
publisher = {Reston, VA: American Institute of Aeronautics and Astronautics, Inc.},
Conference: 2002 AIAA Aircraft Technology, Integration, and Operations (ATIO) Forum, Los Angeles, CA; UNITED STATES; 1-3 Oct. 2002.
Report Number: AIAA Paper 2002-5878.
Number of References: 15.
Publication Type: Conference.
Classification: 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Accession Number: A02-43187 (AH).
Subfile: Aerospace & High Technology (AH).}
Baker, A.P. & Mavris, D.N. Assessing the simultaneous impact of requirements, vehicle characteristics, and technologies during aircraft design
2001 AIAA, Aerospace Sciences Meeting and Exhibit, 39th, Reno, NV; UNITED STATES; 8-11 Jan. 2001 inproceedings
Abstract: The authors present a method which yields a tradeoff environment that allows the simultaneous assessment of technologies, requirements and vehicle characteristics referred to here as the Unified Tradeoff Environment (UTE). The creation of this environment is described along with the tools for its implementation. In addition, a more detailed explanation of the mission requirement space is presented including anticipated uses beyond those associated with the UTE. This environment is illustrated using the Future Transport Rotorcraft as a baseline vehicle. This vehicle epitomizes the new designs, which will rely on technology insertion to meet ambiguous, continually evolving requirements. (Author)
@inproceedings{Baker2001,
author = {Baker, Andrew P and Mavris, Dimitri N},
title = {Assessing the simultaneous impact of requirements, vehicle characteristics, and technologies during aircraft design},
booktitle = {AIAA, Aerospace Sciences Meeting and Exhibit, 39th, Reno, NV; UNITED STATES; 8-11 Jan. 2001},
Conference: AIAA, Aerospace Sciences Meeting and Exhibit, 39th, Reno, NV; UNITED STATES; 8-11 Jan. 2001.
Baker, A.P., Mavris, D.N. & Schrage, D. The role of requirements in conceptual aircraft design and their interactions with technologies and vehicle attributes
2001 (AIAA Paper 2001-5225)AIAA, Aircraft, Technology Integration, and Operations Forum, 1st, Los Angeles, CA; UNITED STATES; 16-18 Oct. 2001 conference
Abstract: In the conceptual design stage, there is an information triad that influences all analysis and decisions. This triad includes the requirements, the concepts, and the technologies that are formulated or chosen and which drive the rest of the design process. The designer's understanding of these aspects in the presence of uncertainty will dictate the decisions he/she makes and ultimately system success. In this paper, the authors present a method which yields a tradeoff environment (referred to here as the Unified Tradeoff Environment (UTE)) that allows for the impact assessment of requirements, vehicle attributes and, technologies on the system level responses and is compatible with probabilistic design techniques. The creation of this environment is described along with the tools for its implementation. This environment is illustrated using the Future Transport Rotorcraft as a baseline vehicle. (Author)
@conference{Baker2001a,
author = {Baker, Andrew P and Mavris, Dimitri N and Schrage, Daniel},
title = {The role of requirements in conceptual aircraft design and their interactions with technologies and vehicle attributes},
booktitle = {AIAA, Aircraft, Technology Integration, and Operations Forum, 1st, Los Angeles, CA; UNITED STATES; 16-18 Oct. 2001},
number = {AIAA Paper 2001-5225},
Conference: AIAA, Aircraft, Technology Integration, and Operations Forum, 1st, Los Angeles, CA; UNITED STATES; 16-18 Oct. 2001.
Report Number: .
Classification: 61 Design Principles (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Accession Number: 200202-61-0985 (MT); A01-43411 (AH).
Baker, A.P., Mavris, D.N. & Schrage, D.P. Assessing the impact of mission requirements, vehicle attributes, technologies and uncertainty in rotorcraft system design
2002 AHS International, 58th Annual Forum Proceedings - Volume II, Montreal, Canada; UNITED STATES; 11-13 June 2002, pp. 1830-1839 conference
Abstract: This research provides a probabilistic design environment for the propagation of design uncertainty to the system level to assist in making more educated decisions in the early stages of design. This design uncertainty is associated with the key elements that are addressed in system design and which are captured in the appropriate design environment, namely mission requirements, vehicle attributes and technologies. The proposed environments are constructed using a metamodeling technique called Response Surface Methodology (RSM) and provide a model relating system-level responses to the mission requirements, vehicle attributes and technologies. The Mission Space Model is concerned with mission requirements exclusively and provides the ability to model an infinite set of missions. The Unified Tradeoff Environment (UTE) integrates the mission requirements, vehicle attributes and technologies in a single environment while allowing both deterministic and probabilistic analyses. The design environments and design methods proposed in this research are demonstrated for a rotorcraft of current interest, namely the Future Transport Rotorcraft, and probabilistic applications are presented. (Author)
@conference{Baker2002,
author = {Baker, A P and Mavris, D N and Schrage, D P},
title = {Assessing the impact of mission requirements, vehicle attributes, technologies and uncertainty in rotorcraft system design},
booktitle = {AHS International, 58th Annual Forum Proceedings - Volume II, Montreal, Canada; UNITED STATES; 11-13 June 2002},
publisher = {Alexandria, VA: AHS International},
pages = {1830-1839},
Conference: AHS International, 58th Annual Forum Proceedings - Volume II, Montreal, Canada; UNITED STATES; 11-13 June 2002.
Bandte, O. & Mavris, D.N. Multi-objective optimization using a joint probabilistic technique
2000 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 8th, Long Beach, CA; UNITED STATES; 6-8 Sept. 2000 conference
Abstract: This paper presents a multidisciplinary design technique that is based on a universally applicable objective function for multi-criteria optimization by combining multi-criteria decision making with probabilistic design. This objective function is based on a multivariate probability distribution in conjunction with a criterion value range of interest that allows the customer or designer to make a decision based on the chance of satisfying the customer's goals. To incorporate a joint probabilistic formulation into the systems design process, the Empirical Distribution Function is extended to accommodate multiple random variables. The design technique developed in this paper is called the Joint Probabilistic Decision Making (JPDM) technique. It is a valuable tool for multiobjective optimization, because of its ability to transform disparate objectives into a single figure of merit; therefore, the likelihood of successfully meeting all goals is possible. This new objective function, called Probability of Success (POS), is a single optimizable function and therefore allows the use of any standard single-objective optimization technique available. By distinguishing between controllable and uncontrollable variables in the design process, the JPDM can account for the uncertain values of the uncontrollable variables that are inherent to the design problem, while facilitating an easy adjustment of the controllable ones to achieve the highest POS possible. Finally, the JPDM is demonstrated on a supersonic transport, where the optimization results show that it can produce a better solution with a higher POS than an Overall Evaluation Criterion approach. (Author)
@conference{Bandte2000,
author = {Bandte, Oliver and Mavris, Dimitri N},
title = {Multi-objective optimization using a joint probabilistic technique},
booktitle = {AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 8th, Long Beach, CA; UNITED STATES; 6-8 Sept. 2000},
Conference: AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 8th, Long Beach, CA; UNITED STATES; 6-8 Sept. 2000.
Classification: 11 Aircraft (MT); 66 SYSTEMS ANALYSIS (AH).
Bandte, O., Mavris, D.N. & DeLaurentis, D.A. Viable designs through a joint probabilistic estimation technique
1999 AIAA and SAE, 1999 World Aviation Conference, San Francisco, CA; UNITED STATES; 19-21 Oct. 1999 conference
Abstract: A key issue in complex systems design is measuring the 'goodness' of a design, i.e., finding a criterion through which a particular design is determined to be the 'best'. Traditional choices in aerospace systems design, such as performance, cost, revenue, reliability, and safety, individually fail to fully capture the life cycle characteristics of the system. Furthermore, current multi-criteria optimization approaches, addressing this problem, rely on deterministic, thus, complete and known information about the system and the environment it is exposed to. In many cases, this information is not available at the conceptual or preliminary design phases. Hence, critical decisions made in these phases have to draw from only incomplete or uncertain knowledge. One modeling option is to treat this incomplete information probabilistically, accounting for the fact that certain values may be prominent, while the actual value during operation is unknown. Hence, to account for a multicriteria as well as a probabilistic approach to systems design, a joint-probabilistic formulation is needed to accurately estimate the probability of satisfying the criteria concurrently. When criteria represent objective/aspiration functions with corresponding goals, this 'joint probability' can also be called viability. The proposed approach to probabilistic, multi-criteria aircraft design, called the Joint Probabilistic Decision-Making (JPDM) technique, will facilitate precisely this estimate. (Author)
author = {Bandte, Oliver and Mavris, Dimitri N and DeLaurentis, Daniel A},
title = {Viable designs through a joint probabilistic estimation technique},
booktitle = {AIAA and SAE, 1999 World Aviation Conference, San Francisco, CA; UNITED STATES; 19-21 Oct. 1999},
Conference: AIAA and SAE, 1999 World Aviation Conference, San Francisco, CA; UNITED STATES; 19-21 Oct. 1999.
Report Number: AIAA Paper 1999-5623; SAE Paper 1999-01-5623.
Other Numbers: Contract: NAG1-1793; NSF DMI-97-34234; N00014-97-0783.
Classification: 11 Aircraft (MT); 65 STATISTICS AND PROBABILITY (AH).
Biltgen, P.T., Ender, T. & Mavris, D.N. Development of a Collaborative Capability-Based Tradeoff Environment for Complex System Architectures
2006 44th AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 9-12 Jan. 2006, pp. 1-11 conference
Abstract: The design of complex systems in the presence of changing requirements, rapidly evolving technologies, and design uncertainty continues to be a challenge. Furthermore, the design of future platforms must take into account the interoperability of a variety of heterogeneous systems and their role in a larger "system-of-systems". To date, methodologies to address the complex interactions and optimize the system at the macro-level have lacked a clear direction and structure and have largely been conducted in an ad-hoc fashion. Traditional optimization has centered around individual vehicles with little regard for the impact on the overall system. A key enabler for reduced cost and cycle time is the ability to rapidly analyze technologies and perform trade studies using a capability-based approach. While many entities have expressed a desire to perform capability-based design, the need for a structured discipline exists. This research will examine how collaboration for the design of such systems-of-systems can be enabled through the use of surrogate models and will demonstrate a top-down analysis methodology for the evaluation of systems and technologies with respect to desired capabilities. A technique for inverse design where any variable can be treated as an independent variable is made routine through the structured use of surrogate models and probability theory. For the testbed demonstration, a depoliticized, notional scenario was postulated to develop a testbed environment in which humanitarian aid and supplies must be delivered to forward-deployed troops for dispersal in a host country under fire.
@conference{Biltgen2006,
author = {Biltgen, Patrick T and Ender, Tommer and Mavris, Dimitri N},
title = {Development of a Collaborative Capability-Based Tradeoff Environment for Complex System Architectures},
booktitle = {44th AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 9-12 Jan. 2006},
publisher = {American Institute of Aeronautics and Astronautics, 1801 Alexander Bell Drive, Suite 500, Reston, VA, 20191-4344, USA, [URL:http://www.aiaa.org]},
Conference: 44th AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 9-12 Jan. 2006.
Classification: 11 Aircraft (MT); 05 Aircraft Design, Testing and Performance (AH).
Accession Number: 200605-11-19791 (MT); A06-05-17614 (AH).
Borer, N. & Mavris, D. Requirements exploration for a notional multi-role fighter
2003 AIAA's 3rd Annual Aviation Technology, Integration, and Operations (ATIO) Technology Conference; Denver, CO; November 17-19. conference
Abstract: Aircraft sizing is typically accomplished through the use of a single design mission that best reflects the most stringent mission requirements. However, many aircraft flying today are tasked with different and often conflicting missions. Current multi-mission sizing methods either size the vehicle to the most stringent of these missions or create a compromise design by deterministically weighting various requirement attributes to form an overall evaluation criterion that is then optimized. An approach is outlined in this paper that allows the designer to explore a combined design and mission space for a vehicle concept with multiple missions and requirements. This process allows for the use of Monte Carlo simulation and metamodeling to efficiently explore high-dimensional spaces. Multi-criteria decision methods are used to rank the representative population of the design/mission space via probabilistic weight factors. A logical method is presented to aid in the determination of the distributions and ranges of each weight factor, as well as to reduce the overall dimensionality of the problem. This process is illustrated on a single configuration of a notional multi-role fighter with nine distinct missions and a total of 44 decision metrics.
@conference{Borer2003,
author = {Borer, N.K. and Mavris, D.N.},
title = {Requirements exploration for a notional multi-role fighter},
booktitle = {AIAA's 3rd Annual Aviation Technology, Integration, and Operations (ATIO) Technology Conference; Denver, CO; November 17-19.},
publisher = {American Institute of Aeronautics and Astronautics, Inc , Reston, VA, 20191-4344, United States},
Conference: AIAA's 3rd Annual Aviation Technology, Integration, and Operations (ATIO) Technology Conference; Denver, CO; November 17-19, 2003.
Publication Type: Meeting Paper.
Update: 2003.
Borer, N.K. & Mavris, D.N. Relative Importance Modeling in the Presence of Uncertainty and Interdependent Metrics
2006 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference conference
Abstract: Modern systems design problems are characterized by the necessity to identify and enable multiple tradeoffs. This can be accomplished by transformation of the design problem to a multiple objective optimization formulation. However, existing multiple criteria techniques can lead to unattractive solutions due to their assumption of independent decision criteria. This, combined with static relative importance values, can quickly lead MCDM to unattractive design solutions. These problems are magnified by uncertainty in the relative importance due to the high potential for variability in these numbers. This paper presents a discussion and application of Multiple Criteria Decision Making (MCDM) to a systems design problem and discusses the uncertainties in modern techniques. It then identifies a strategy for minimizing the effects of uncertainty and interdependence by suggesting a two-part relative importance model for each criterion. This model builds on the authors' previous work on the subject by including an interdependence correction as well as a method to simulate uncertainty in the user-specified relative importance.
author = {Borer, Nicholas K and Mavris, Dimitri N},
title = {Relative Importance Modeling in the Presence of Uncertainty and Interdependent Metrics},
booktitle = {11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference},
Conference: 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference; Portsmouth, VA; USA; 6-8 Sept. 2006.
Publication Type: Conference Paper; Journal Article.
Classification: 10 Aerospace Engineering (General) (MT); 59 Mathematical and Computer Sciences (General) (AH); 51 Theoretical Computation (CI).
Accession Number: 200701-10-015441 (MT); A06-59-003094 (AH); 200701-51-003385 (CI).
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH); Computer & Information Systems (CI).}
Borer, N.K. & Mavris, D.N. Multiple Criteria Decision Making for Large Scale Systems Design
2005 AIAA 5th Aviation, Technology, Integration, and Operations Conference (ATIO); Arlington, VA; USA; 26-28 Sept. 2005, pp. 1-15 conference
Abstract: Modern systems design problems are often characterized by the necessity to identify and enable multiple tradeoffs. This can be accomplished by transformation of the design problem to a multiple objective optimization formulation. However, existing multiple criteria techniques can lead to unattractive solutions due to their basic assumptions; namely that of monotonically increasing utility and independent decision criteria. Further, it can be difficult to quantify the relative importance of each decision metric, especially as the number of criteria grow. This paper presents a discussion and application of Multiple Criteria Decision Making (MCDM) to an example systems design problem with several requirements and quantifies the complications associated with switching from single to multiple objectives. It then presents a modified procedure for MCDM to tackle these problems by utilizing a two-part relative importance model for each criterion. This model contains a static and dynamic portion with respect to the current value of the decision metric. The static portion is selected based on an entropy analogy of each metric within the decision space to alleviate the problems associated with quantifying basic (monotonic) relative importance. The dynamic contribution uses a penalty function approach for any constraints and further reduces the importance of any metric approaching a user-specified threshold level. This reduces the impact of the assumption of monotonically increasing utility by constantly updating the relative importance of a given metric based on its current value.
title = {Multiple Criteria Decision Making for Large Scale Systems Design},
booktitle = {AIAA 5th Aviation, Technology, Integration, and Operations Conference (ATIO); Arlington, VA; USA; 26-28 Sept. 2005},
Conference: AIAA 5th Aviation, Technology, Integration, and Operations Conference (ATIO); Arlington, VA; USA; 26-28 Sept. 2005.
Classification: 05 Aircraft Design, Testing and Performance (AH).
Accession Number: A05-05-52248 (AH).
Subfile: Aerospace & High Technology (AH).
Cited by: 1 (on Mar 09, 2007).}
Borer, N.K. & Mavris, D.N. Formulation of a multi-mission sizing methodology for competing configurations
2004 42nd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; Jan. 5-8. conference
Abstract: The creation of long design cycle time vehicles such as aircraft often shrouds the true requirements the vehicle will face in its operational life. The requirements that seem to dominate decisions early in the design may be obsolete by the time the vehicle reaches the operational stage. Other, formerly less stringent or less important requirements may come to the forefront and present challenges to a product already near production, resulting in high cost to change or diminished performance. This problem is compounded in the design of multi-mission aircraft, as the attributes of one mission that dominates decisions made today may not in the future. Furthermore, the design team may have several system configurations in mind at the early stages of multi-role vehicle design, and one configuration that appears attractive may ultimately not be in the face of evolving requirements. This paper presents a method that makes use of surrogate, reduced-order models to increase computational efficiency coupled with probabilistic techniques to account for uncertainty in the requirements parameters. This method can ultimately be used to help a design team select a representative set of requirements for the design of multi-mission aircraft. It also provides for assistance in selecting the overall vehicle configuration that can best meet these requirements. This process is partially illustrated on a notional multi-role fighter designed to replace three legacy aircraft.
author = {Borer, Nicholas K. and Mavris, Dimitri N.},
title = {Formulation of a multi-mission sizing methodology for competing configurations},
booktitle = {42nd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; Jan. 5-8.},
Conference: 42nd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; Jan. 5-8, 2004.
Branscome, C. & Mavris, D. A regression confidence band approach to global optimization
2004 10th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference; Albany, NY; Aug. 30 - Sep. 1. conference
Abstract: A general algorithm called Domain Spanning Robust Optimization (DSRO) is proposed for global optimization. The algorithm, belonging to the class of sequential metamodeling algorithms, employs a confidence band as a point selection and stopping criterion. The authors have implemented an algorithm which employs a Working-Hotelling Confidence Band for point selection and iteration termination for the purpose of experimenting with the approach. Evaluation indicates fairly efficient and robust optimization for lower-dimensional problems having a wide range of function characteristics typical of Multidisciplinary Design Optimization problems such as objective functions which are: costly to evaluate; convex/constrained; multimodal; noisy; and those for which derivative information is not available.
@conference{Branscome2004,
author = {Branscome, Caleb and Mavris, Dimitri},
title = {A regression confidence band approach to global optimization},
booktitle = {10th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference; Albany, NY; Aug. 30 - Sep. 1.},
Conference: 10th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference; Albany, NY; Aug. 30 - Sep. 1, 2004.
Classification: 59 Mathematical and Computer Sciences (General) (AH).
Brewer, J.T., Mavris, D.N. & Schrage, D.P. Implementation of Georgia Tech's concurrent engineering methodology to a high speed civil transport (HSCT)
1994 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 5th, Panama City Beach, FL, Technical Papers. Pt. 1; UNITED STATES; 7-9 Sept. 1994, pp. 731-741 conference
Abstract: The School of Aerospace Engineering at Georgia Tech has been working over the past three years under a NASA Advanced Design grant to develop a comprehensive methodology for the integration of design and manufacturing in its graduate curriculum. NASA's High Speed Civil Transport (HSCT) concept was selected for this study. The design of an HSCT configuration was made the focus of each and every one of the five design courses that form the aerospace graduate curriculum. The students enrolled in this sequence of courses were exposed to Georgia Tech's Concurrent Engineering (CE) or Integrated Product and Process Development (IPPD) methodology and overall design philosophy. They were then given the task of applying this methodology to the design of an HSCT. In this paper, Georgia Tech's CE/IPPD methodology is presented in depth along with an account of the team's efforts to apply this methodology, generate feasible candidate configurations, evaluate them, and select the optimum one. The comparison criterion selected for this evaluation was the economic impact of this aircraft, measured in terms of average yield per Revenue Passenger Mile ($/RPM), while the selection process was facilitated through the use of a parameter design optimization based method. (Author)
@conference{Brewer1994,
author = {Brewer, Jason T and Mavris, Dimitri N and Schrage, Daniel P},
title = {Implementation of Georgia Tech's concurrent engineering methodology to a high speed civil transport (HSCT)},
booktitle = {AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 5th, Panama City Beach, FL, Technical Papers. Pt. 1; UNITED STATES; 7-9 Sept. 1994},
publisher = {Washington, DC: American Institute of Aeronautics and Astronautics},
Conference: AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 5th, Panama City Beach, FL, Technical Papers. Pt. 1; UNITED STATES; 7-9 Sept. 1994.
Notes: Technical Papers. Pt. 1 (A94-36228 12-66).
Briceno, S.I., Buonanno, M.A., Fernandez, I. & Mavris, D.N. A parametric exploration of supersonic business jet concepts utilizing response surfaces
Abstract: Market forecasts predict a potentially large market for a quiet supersonic business jet provided that several technical hurdles are overcome prior to fielding such a vehicle. In order to be acceptable, the QSJ must be able to fly at supersonic speeds over land and operate from regional airports while meeting government noise and emissions requirements. Physics based analysis tools are used in conjunction with a Response Surface metamodeling approach to create an environment in which the performance, economics, and environmental impact of the aircraft can be studied as a function of design and mission parameters. Through the use of this environment, the designer is able to rapidly explore the entire concept space by dynamically modifying the configuration, engine cycle, and requirements. Results obtained using this exploration tool indicate that it may be possible to meet emissions and noise requirements, but that technology infusion will be required in order to meet all performance and economic goals. Finally, this same physics-based environment was used to assess the impact of a portfolio of technologies on the system's acceptability. (Author)
@inproceedings{Briceno2002,
author = {Briceno, Simon I and Buonanno, Michael A and Fernandez, Ismael and Mavris, Dimitri N},
title = {A parametric exploration of supersonic business jet concepts utilizing response surfaces},
Briceno, S.I. & Mavris, D.N. Strategic Decision-Making: Applications of Game Theory in a Systems Approach to Commercial Engine Selection
Abstract: Engine development programs present difficult and complex problems for manufacturers. The decision making process consists of analyzing the technical and financial potential of the company and determining what feasible and viable solutions exist. The technical requirements have historically been addressed through performance analyses using "physics-based" codes. To assess viability, firms typically carry out extensive market and financial analyses in order to justify the economic viability of the engine programs. However, these analyses typically fail to consider competitive market uncertainties due to limited information about the competitor and the market. As a result, companies often use subjective means to predict their competitors' strategic actions. The use of Game Theory is explored as a method to assist the selection process of commercial engine architectures in the presence of competitive uncertainties. A strategic simulation model is developed that represents the decision analysis for a particular engine company. Information is continuously fed back from the market (and competitors) in order to design and select the most profitable and competitive engines. Game theory-enabled analysis integrated into this simulation at the strategic decision model provides a basis for a systematic exploration of both engineering and business decisions. The analysis employs game theories to enumerate the decisions (moves) available and to formulate a process by which a winning decision is achieved. This new capability enhances the decision maker's ability to understand the engine game and become more successful at making strategic choices.
@conference{Briceno2005,
author = {Briceno, Simon I and Mavris, Dimitri N},
title = {Strategic Decision-Making: Applications of Game Theory in a Systems Approach to Commercial Engine Selection},
Classification: 07 Aircraft Propulsion and Power (AH).
Bucovsky, A.E., Jesse & Mavris, D. Design Space Exploration for Boom Mitigation on a Quiet Supersonic Business Jet
Abstract: Research indicates that a strong market potential exists for a supersonic business jet (SBJ) as long as it satisfies certain customer criteria, the most important of which is the ability to fly over land at any time of the day or night. To achieve this, the aircrafts sonic boom must be mitigated to an acceptable noise level. Although sonic booms are a physically inescapable consequence of traveling faster than the speed of sound, past research suggests that certain techniques can be employed to shape the boom into a less audible form. The most straightforward and effective of these methods involves altering the aircrafts shape and lift distribution to help increase the rise time and decrease the maximum overpressure of the perceived sonic boom at ground level. Using an integrated computer design environment and a design of experiments (DoE) technique, a series of orthogonal arrays are constructed around a baseline SBJ configuration provided by the Gulfstream Aerospace Corporation. Response Surface Equations (RSEs), representing major performance and economic metrics, were generated and used to obtain an overall optimized system. The final aircraft was 120,660 lbs with a range of 4,500 nm, and a cost of 97.2 million in 2003 dollars. In addition, its sonic boom signature was a sharply defined N-wave with a maximum overpressure of 0.977 PSF. Although this represents a marked improvement over the baseline vehicle, additional improvements are needed to produce a viable and feasible aircraft. This methodology, however, is sound and can be used to further investigate the design space of a supersonic business jet system.
@conference{Bucovsky2003,
author = {Bucovsky, Adrian Eyer, and Jesse and Mavris, Dimitri},
title = {Design Space Exploration for Boom Mitigation on a Quiet Supersonic Business Jet},
Buonanno, M.A. & Mavris, D.N. A New Method for Aircraft Concept Selection Using Multicriteria Interactive Genetic Algorithms
2005 43rd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 10-13 Ja. 2005, pp. 12 conference
Abstract: The problem of aircraft concept selection has become increasingly difficult in recent years as a result of a change from performance as the primary evaluation criteria of aircraft concepts to the current situation in which environmental effects, economics, and aesthetics must also be evaluated and considered in the earliest stages of the decision-making process. This has prompted a shift from design using historical data regression techniques for metric prediction to the use of physics-based analysis tools that are capable of analyzing designs outside of the historical database. The use of optimization methods with these physics-based tools, however, has proven difficult because of the tendency of optimizers to exploit assumptions present in the models and drive the design towards a solution which, while promising to the computer, may be infeasible due to factors not considered by the computer codes. In addition to this difficulty, the number of discrete options available at this stage may be unmanageable due to the combinatorial nature of the concept selection problem, leading the analyst to arbitrarily choose a sub-optimum baseline vehicle. These concept decisions such as the type of control surface scheme to use, though extremely important, are frequently made without sufficient understanding of their impact on the important system metrics because of a lack of computational resources or analysis tools. This paper describes a hybrid subjective/quantitative optimization method and its application to the concept selection of a Small Supersonic Transport. The method uses Genetic Algorithms to operate on a population of designs and promote improvement by varying more than sixty parameters governing the vehicle geometry, mission, and requirements. In addition to using computer codes for evaluation of quantitative criteria such as gross weight, expert input is also considered to account for criteria such as aeroelasticity or manufacturability which may be impossible or too computationally expensive to consider explicitly in the analysis. Results indicate that concepts resulting from the use of this method represent designs which are promising to both the computer and the analyst, and that a mapping between concepts and requirements that would not otherwise be apparent is revealed.
@conference{Buonanno2005,
author = {Buonanno, Michael A and Mavris, Dimitri N},
title = {A New Method for Aircraft Concept Selection Using Multicriteria Interactive Genetic Algorithms},
booktitle = {43rd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 10-13 Ja. 2005},
pages = {12},
Conference: 43rd AIAA Aerospace Sciences Meeting and Exhibit; Reno, NV; USA; 10-13 Ja. 2005.
Buonanno, M.A. & Mavris, D.N. Small Supersonic Transport Concept Evaluation Using Interactive Evolutionary Algorithms
2004 AIAA 4th Aviation Technology, Integration and Operations (ATIO) Forum; Chicago, IL; USA; 20-22 Sept. 2004, pp. 1-16 conference
Abstract: The problem facing aircraft designers has grown much more complicated in recent years as a result of a shift from performance as the dominant evaluation criteria of aircraft concepts to the current situation in which environmental effects, economics, and aesthetics must also be evaluated and considered in the earliest stages of the decision-making process. This has prompted a shift from design using historical data regression techniques for metric prediction to the use of physics-based analysis tools that are capable of analyzing designs outside of the historical database. The use of optimization methods with these physics-based tools, however, has proven difficult because of the tendency of optimizers to exploit assumptions present in the analyses and drive the design towards a solution which, while promising to the computer, may be infeasible due to factors not considered by the computer codes. In addition to this difficulty, the number of discrete options available at this stage may be unmanageable due to the combinatorial nature of the concept selection problem, leading the analyst to arbitrarily choose a sub-optimum design. This paper describes a hybrid subjective/quantitative optimization method and its applications to the concept selection of a Small Supersonic Transport. The method uses Genetic Algorithms to operate on a population of designs and promote improvement, yet in addition to using computer codes for evaluation of fitness metrics expert input is also considered in order to account for criteria such as manufacturability, which may be impossible or too computationally expensive to consider explicitly in the analysis. Results indicate that concepts resulting from the use of this method represent designs which are promising to both the computer and the analyst.
title = {Small Supersonic Transport Concept Evaluation Using Interactive Evolutionary Algorithms},
booktitle = {AIAA 4th Aviation Technology, Integration and Operations (ATIO) Forum; Chicago, IL; USA; 20-22 Sept. 2004},
Conference: AIAA 4th Aviation Technology, Integration and Operations (ATIO) Forum; Chicago, IL; USA; 20-22 Sept. 2004.
Buonanno, M. & Mavris, D. Aerospace vehicle concept selection using parallel, variable fidelity genetic algorithms
Abstract: In recent years a large amount of work has been done by both industry and academia in order to improve preliminary aircraft design methods. These new techniques have helped to bring about a paradigm shift that allows designers to gain insight into the impact of the configuration parameters on system acceptability early in the design process before excessive resources have been committed. Despite these advances, little progress has been made in creating rigorous methods to aid in the first stages of conceptual design. Currently, the prevailing method is to use qualitative techniques to select a handful of designs from the billions possible and then perform detailed analysis on each of these concepts in order to determine its performance and characteristics. Other methods have also been introduced to help the decision maker choose which concept from that handful is most worthy of further investigation based upon criteria limits, but these instantly exclude the vast majority of the concept space based on the designers intuition or biases and may prevent the selection of the best concept for the design mission. This paper describes the development and application of a modified Genetic Algorithm to the aircraft concept selection problem, and gives results for the optimization of a notional small supersonic transport.
@conference{Buonanno2004a,
author = {Buonanno, Michael and Mavris, Dimitri},
title = {Aerospace vehicle concept selection using parallel, variable fidelity genetic algorithms},
Burdun, I.Y., DeLaurentis, D.A. & Mavris, D.N. Modeling and simulation of airworthiness requirements for an HSCT prototype in early design
1998 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO, Collection of Technical Papers. Pt. 3; UNITED STATES; 2-4 Sept. 1998, pp. 1750-1759 conference
Abstract: An attempt is made to map some of the airworthiness requirements (FAR, Part 25) into computational algorithms, data structures, and flight modeling experiments for a high-speed civil transport airplane (HSCT). The objective is to develop and test a method for virtual flight testing and certification of an HSCT prototype in the earlier design phases. An autonomous situational model of flight is employed as a substitute for a flight test article. Formal test flight scenarios which map the airworthiness requirements for takeoff are described. Examples of autonomous modeling and simulation of two takeoff situations are presented. (Author)
@conference{Burdun1998,
author = {Burdun, Ivan Y and DeLaurentis, Daniel A and Mavris, Dimitri N},
title = {Modeling and simulation of airworthiness requirements for an HSCT prototype in early design},
booktitle = {AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO, Collection of Technical Papers. Pt. 3; UNITED STATES; 2-4 Sept. 1998},
publisher = {Reston, VA: American Institute of Aeronautics and Astronautics},
Conference: AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO, Collection of Technical Papers. Pt. 3; UNITED STATES; 2-4 Sept. 1998.
Notes: Collection of Technical Papers. Pt. 3 (A98-39701 10-31).
Number of References: 5.
Burdun, I.Y. & Mavris, D.N. A technique for testing and evaluation of aircraft flight performance during early design phases
1997 AIAA and SAE, 1997 World Aviation Congress, Anaheim, CA; UNITED STATES; 13-16 Oct. 1997 inproceedings
Abstract: A technique is proposed for examining complex behaviors in the 'pilot - vehicle - operational conditions' system using an autonomous situational model of flight. The goal is to identify potentially critical flight situations in the system behavior early in the design process. An exhaustive set of flight scenarios can be constructed and modeled on a computer by the designer in accordance with test certification requirements or other inputs. Distinguishing features of the technique include the autonomy of experimentation (the pilot and a flight simulator are not involved) and easy planning and quick modeling of complex multifactor flight cases. An example of mapping airworthiness requirements into formal scenarios is presented. Simulation results for various flight situations and aircraft types are also demonstrated.
@inproceedings{Burdun1997,
author = {Burdun, Ivan Y and Mavris, Dimitri N},
title = {A technique for testing and evaluation of aircraft flight performance during early design phases},
booktitle = {AIAA and SAE, 1997 World Aviation Congress, Anaheim, CA; UNITED STATES; 13-16 Oct. 1997},
Conference: AIAA and SAE, 1997 World Aviation Congress, Anaheim, CA; UNITED STATES; 13-16 Oct. 1997.
Report Number: AIAA Paper 1997-5541; SAE Paper 975541.
Burdun, I.Y., Mavris, D.N. & Sannikov, V.A. A generic mathematical model of groundroll motion of a high speed transport airplane
1998 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO; UNITED STATES; 2-4 Sept. 1998, pp. 1760-1770 conference
Abstract: A mathematical model of the 'pilot-airplane-undercarriage-operational conditions' system developed for a high-speed transport airplane is introduced. The algorithms of the airplane flight dynamics, undercarriage-runway interaction, and human pilot situational decision making are briefly described. The overall objective is to develop an affordable engineering tool for examination of complex system behaviors in the groundroll and adjacent phases of flight on a computer during design. (Author)
@conference{Burdun1998b,
author = {Burdun, Ivan Y and Mavris, Dimitri N and Sannikov, Vladimir A},
title = {A generic mathematical model of groundroll motion of a high speed transport airplane},
booktitle = {AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO; UNITED STATES; 2-4 Sept. 1998},
Conference: AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO; UNITED STATES; 2-4 Sept. 1998.
Classification: 8 AIRCRAFT STABILITY AND CONTROL (AH).
Burdun, I.Y., Mavris, D.N., Schrage, D.P. & Yavrucuk, I. Computer simulation of selected failure modes and operational conditions for rotorcraft
1998 Heli Japan 98; Proceedings of the AHS International Meeting on Advanced Rotorcraft Technology and Disaster Relief, Gifu, Japan; UNITED STATES; 21-23 Apr. 1998, pp. 95-101 conference
Abstract: The purpose of aircraft certification is to ensure that a given aircraft is initially safe to fly and will continue to be safe if certain operating and maintenance limitations and procedures are followed. Technology advances and economic pressures are rapidly transforming aviation into a fully integrated but very complex system, thus making it more difficult to examine complex behaviors in the 'pilot-vehicle-operational conditions' system. Modeling and simulation has become one of the most efficient ways to design and investigate new aircraft. The problem under study is how to check and evaluate flight safety or mission success standards for a new vehicle beginning with the early design and certification phases. This paper presents a technique for examining complex behaviors in the 'pilot-vehicle-operational conditions' system using an autonomous situational model of flight. This approach allows virtual testing and evaluation as an emerging method which employs mathematical modeling and computer simulation for examining vehicle dynamics and flight control under complex operational conditions. An example is provided for a tilt-rotor aicraft, using a dynamics model of the XV-15 tilt rotor research aircraft. (Author)
@conference{Burdun1998a,
author = {Burdun, Ivan Y and Mavris, Dimitri N and Schrage, Daniel P and Yavrucuk, Ilkay},
title = {Computer simulation of selected failure modes and operational conditions for rotorcraft},
booktitle = {Heli Japan 98; Proceedings of the AHS International Meeting on Advanced Rotorcraft Technology and Disaster Relief, Gifu, Japan; UNITED STATES; 21-23 Apr. 1998},
publisher = {Alexandria, VA: American Helicopter Society},
pages = {95-101},
Conference: Heli Japan 98; Proceedings of the AHS International Meeting on Advanced Rotorcraft Technology and Disaster Relief, Gifu, Japan; UNITED STATES; 21-23 Apr. 1998.
Cartagena, M.A., Rosario, J.E. & Mavris, D.N. A method for technology identification, evaluation, and selection of aircraft propulsion systems
2000 AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 36th, Huntsville, AL; UNITED STATES; 16-19 July 2000 conference
Abstract: The objective of this paper is to develop and implement a Technology Identification, Evaluation, and Selection Methodology (TIES) for the analysis of aircraft gas turbine propulsion systems. This is done in part through the creation of an interactive environment that allows the designer to evaluate in real time the impact of changes in the engine design on aircraft-level parameters. The TIES methodology is a key to enabling accurate multidisciplinary analysis, while simultaneously reducing design cycle time. This environment is then used as a tool to analyze the impact of several specific engine technologies on the performance and affordability of a notional large commercial transport. The issue of technology uncertainty is addressed via a probabilistic approach in which uncertainty is expressed in terms of the probability (or confidence) of meeting design goals and constraints. The result is a method allowing analytical quantification of the risk and uncertainty associated with the infusion of new technologies into an engine. Finally, a formalized and rational approach is presented for optimal allocation of scarce research dollars amongst technologies that have the highest probability of successfully meeting the design and economic objectives. (Author)
@conference{Cartagena2000,
author = {Cartagena, Miguel A and Rosario, Javier E and Mavris, Dimitri N},
title = {A method for technology identification, evaluation, and selection of aircraft propulsion systems},
booktitle = {AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 36th, Huntsville, AL; UNITED STATES; 16-19 July 2000},
Conference: AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 36th, Huntsville, AL; UNITED STATES; 16-19 July 2000.
Classification: 11 Aircraft (MT); 7 AIRCRAFT PROPULSION AND POWER (AH).
Choi, T.P., Soban, D.S. & Mavris, D.N. Creation of a Design Framework for All-Electric Aircraft Propulsion Architectures
2005 3rd International Energy Conversion Conference; San Francisco, CA; USA; 15-18 Aug. 2005, pp. 11 conference
Abstract: This paper summarizes the achievements of a research-in-progress that aims to create an integrated design framework for all-electric aircraft propulsion architectures. The examination of modeling approaches towards parametrically designing, analyzing, and sizing an example electric aircraft propulsion architecture is presented as the preliminary investigation into this ideology. Lessons learned from this study is envisioned to help identify those areas in which new methodological contributions can be made.
@conference{Choi2005,
author = {Choi, Taeyun P and Soban, Danielle S and Mavris, Dimitri N},
title = {Creation of a Design Framework for All-Electric Aircraft Propulsion Architectures},
booktitle = {3rd International Energy Conversion Conference; San Francisco, CA; USA; 15-18 Aug. 2005},
Conference: 3rd International Energy Conversion Conference; San Francisco, CA; USA; 15-18 Aug. 2005.
Daberkow, D.D. & Mavris, D.N. An investigation of metamodeling techniques for complex systems design
2002 9th AIAA/ISSMO Symposium and Exhibit on Multidisciplinary Analysis and Optimization, Atlanta, GA; UNITED STATES; 4-6 Sept. 2002 inproceedings
Abstract: A new metamodel implementation process to be used in complex systems design, utilizing a Gaussian Process (GP) prediction method, is formulated. It is based on a Bayesian probability and inference approach and as such assigns a probability distribution as a new prediction, rather than estimating a single value. This distribution is considered to be Gaussian, and the method returns a variance prediction along with the most likely value. Compared to other metamodeling techniques, it thus gives an estimate also for the confidence in its prediction, in addition to the value of the prediction itself. In this paper, the theory of this prediction via Bayesian regression is introduced, and the method is contrasted to other regression metamodeling techniques, such as Response Surface Equations (RSEs) and Neural Networks (NNs). An implementation process is formulated, making the GP method accessible for complex systems design; its applicability and appropriateness at the theoretical as well as practical level are investigated, and proof-of-concept implementations at the system level are provided. In addition to the capability of giving a confidence estimate, it also shows consistent improvements in accuracy over a standard quadratic model RSE metamodel implementation. (Author)
@inproceedings{Daberkow2002,
author = {Daberkow, Debora D and Mavris, Dimitri N},
title = {An investigation of metamodeling techniques for complex systems design},
booktitle = {9th AIAA/ISSMO Symposium and Exhibit on Multidisciplinary Analysis and Optimization, Atlanta, GA; UNITED STATES; 4-6 Sept. 2002},
Conference: 9th AIAA/ISSMO Symposium and Exhibit on Multidisciplinary Analysis and Optimization, Atlanta, GA; UNITED STATES; 4-6 Sept. 2002.
Classification: 66 SYSTEMS ANALYSIS (AH).
Danner, T. & Mavris, D. Foundational Concepts for a Work Potential-Based Design Methodology
Abstract: This paper outlines the foundational concepts and the initial formulation of a methodology for revolutionary energy systems identification and design. Fundamental laws of physics, thermodynamic optimization, and a form of energy analysis establish the foundation for this methodology. The ultimate objective is to develop a physics-based methodology to provide the capacity to identify revolutionary systems capable of achieving a specified objective most effectively and efficiently. The method has been formulated with a multilevel structure to facilitate this broad applicability to many aspects and phases of system development from system identification and conceptual design to subsystem detailed design. It provides the necessary generalized tools to consider a wide range of potential concepts in the absence of concept specific analysis tools - immediately providing results adequate for comparison. Once a concept has been selected, the method also provides a common framework within which all concept subsystems can be designed and optimized for common system level objectives. The concepts presented in this paper form the foundation of what is expected to mature into a holistic work potential-based developmental methodology providing for the complete design and optimization of energy systems taking under consideration technical, economic, and environmental issues.
@conference{Danner2003,
author = {Danner, Travis and Mavris, Dimitri},
title = {Foundational Concepts for a Work Potential-Based Design Methodology},
De Baets, P., Mavris, D. & Sobieszczanski-Sobieski, J. Aeroelastic design by combining conventional practice with Bi-Level Integrated System Synthesis (BLISS)
Abstract: The research examines how the Bi-Level Integrated System Synthesis decomposition technique can be adapted to perform as a key tool in conceptual aeroelastic design. The study describes a comprehensive solution of the aeroelastic coupled problem cast in this decomposition format and implementation in an integrated framework. The method connects traditional designer practices with the results obtained with the Bi-Level Integrated System Synthesis in order to plot an aeroelastic constraint boundary. Physics-based codes such as finite element and an aerodynamic panel method are used to model the high- definition geometric characteristics of the vehicle. A synthesis and sizing code is added to referee the conflicts that arise between the two disciplines. The methods application to the quiet supersonic business jet gave a delta shaped wing for the supersonic speed regime. The scaling approach allowed iso-flutter and iso-divergence lines to be plotted. The main effects of velocity, altitude, and angle of attack on these iso-lines were also discussed, as was the identification of robust design space. The response surface surrogate models allowed convergence of the system optimization but questions were posed as to the accuracy of these quadratic models.
@conference{De2004,
author = {De Baets, Peter and Mavris, Dimitri and Sobieszczanski-Sobieski, Jaroslaw},
title = {Aeroelastic design by combining conventional practice with Bi-Level Integrated System Synthesis (BLISS)},
De Baets, P.W.G. & Mavris, D.N. Potential formulation for aeroelastic constraint analysis in a conceptual design environment
2002 43rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Denver, CO; UNITED STATES; 22-25 Apr. 2002 inproceedings
Abstract: The paper defines an innovative, novel design methodology that results in a product that effectively satisfies the designer's needs and requirements. Use is made of the response surface methodology after consideration of other metamodeling techniques. Drawbacks of the response surface methodology are mitigated by incorporating sensitivity information in the response surface creation. The definition, application, and eventual implementation of this emerging design tool for new product design is described. The new methodology envisioned will make use of the bi-level integrated system synthesis decomposition for distributed computing. The overall goal is to accomplish cheaper, faster, better designs for structural systems and components. This research leads to the discussion of the use of design tools for structural optimization, including the dynamic aeroelastic constraints. (Author)
@inproceedings{De2002,
author = {De Baets, Peter W G and Mavris, Dimitri N},
title = {Potential formulation for aeroelastic constraint analysis in a conceptual design environment},
booktitle = {43rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Denver, CO; UNITED STATES; 22-25 Apr. 2002},
Conference: 43rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Denver, CO; UNITED STATES; 22-25 Apr. 2002.
De Baets, P.W.G. & Mavris, D.N. Methodology for the parametric structural conceptual design of hypersonic vehicles
2000 2000 World Aviation Conference, San Diego, CA; UNITED STATES; 10-12 Oct. 2000 conference
Abstract: The design of hypersonic vehicles is influenced by tightly coupled interactions between aerodynamics, propulsion, and structures. Therefore, in the conceptual design phases, the identification and mitigation of potential problem areas and disciplinary interrelations are critical. Although the multidisciplinary character of hypersonic designs is well known, research in hypersonics is primarily focused on the isolated disciplines with side notes on the interactions. The designer has to integrate all the disciplinary information and create a successful system. This integration is a tedious and elaborate process involving time-consuming iterations. This paper proposes a new approach and entails the creation of response surface equations from the various constituent disciplines considered. This method allows one to quickly assess the implication of design decisions at the top level using the multiple disciplinary meta-models. As an exercise, the paper demonstrates the generation of a structural meta-model for a hypersonic strike fighter that must fulfill certain mission requirements. (Author)
author = {De Baets, P W G and Mavris, D N},
title = {Methodology for the parametric structural conceptual design of hypersonic vehicles},
booktitle = {2000 World Aviation Conference, San Diego, CA; UNITED STATES; 10-12 Oct. 2000},
Conference: 2000 World Aviation Conference, San Diego, CA; UNITED STATES; 10-12 Oct. 2000.
De Baets, P.W.G., Mavris, D.N. & Battoo, R.S. Aeroelastic analysis of a composite wingbox with varying root flexibility
2000 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 41st, Atlanta, GA; UNITED STATES; 3-6 Apr. 2000 conference
Abstract: The authors studied the aeroelastic properties and modal response of a composite rectangular wingbox in an attempt to assess the sensitivity of the flutter speed, divergence speed, and modal response when varying the composite skin lay-up, fiber orientation, and the root flexibility of the model. All this research was conducted using the finite element code ASTROS. An attempt was made to cover as extensive a field as possible and identify interesting areas that required further examination. Interesting relations were found between the following properties: E1/GJ versus fiber orientation and various mode ratios versus root stiffness. These could be linked with the changes in flutter and divergence speed of the composite model. In certain regions of the root flexibility, the flutter and divergence speeds showed dips and peaks. These coincided with changes in modal behavior and were verified with a visualization tool. (Author)
@conference{De2000a,
author = {De Baets, Peter W G and Mavris, Dimitri N and Battoo, Rupinder S},
title = {Aeroelastic analysis of a composite wingbox with varying root flexibility},
booktitle = {AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 41st, Atlanta, GA; UNITED STATES; 3-6 Apr. 2000},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 41st, Atlanta, GA; UNITED STATES; 3-6 Apr. 2000.
Classification: 63 Mathematics and Computation (CE); 63 Mathematics and Computation (MT); 39 STRUCTURAL MECHANICS (AH).
Accession Number: 2001-63-033852 (CE); 2001-63-006091 (MT); A00-24738 (AH).
Subfile: Civil Engineering (CE); Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH).}
DeLaurentis, D.A., Cesnik, C.E.S., Lee, J.-M. & Mavris, Dimitri N; Schrage, D.P. A new approach to integrated wing design in conceptual synthesis and optimization
1996 AIAA, NASA, and ISSMO, Symposium on Multidisciplinary Analysis and Optimization, 6th, Bellevue, WA, Technical Papers. Pt. 2; UNITED STATES; 4-6 Sept. 1996, pp. 1835-1843 conference
Abstract: This paper puts forward a new approach to achieving a balance between modeling fidelity and required accuracy. Higher fidelity analysis techniques, usually associated with design stages where key geometric variables have been fixed, are used to model a design space consisting of these important geometric variables. This is accomplished through the combined use of a Design of Experiment/Response Surface Method technique and parametric analysis tools (including an automated finite element grid generation procedure). The result is a prediction method for the structural weight of an aeroelastically optimized wing for use in an Integrated Product and Process Development environment, where cost, performance, and manufacturing trades can he accomplished. The technique is to be demonstrated on the aeroelastic design of a wing for a generic high speed civil transport, based on a select set of planform and airfoil design variables. A framework for evaluating new technologies within the aeroelastic optimization is outlined. (Author)
@conference{DeLaurentis1996a,
author = {DeLaurentis, Daniel A and Cesnik, Carlos E S and Lee, Jae-Moon and Mavris, Dimitri N; Schrage, Daniel P},
title = {A new approach to integrated wing design in conceptual synthesis and optimization},
booktitle = {AIAA, NASA, and ISSMO, Symposium on Multidisciplinary Analysis and Optimization, 6th, Bellevue, WA, Technical Papers. Pt. 2; UNITED STATES; 4-6 Sept. 1996},
Conference: AIAA, NASA, and ISSMO, Symposium on Multidisciplinary Analysis and Optimization, 6th, Bellevue, WA, Technical Papers. Pt. 2; UNITED STATES; 4-6 Sept. 1996.
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH).
DeLaurentis, D.A., Mavris, D.N., Calise, A.J. & Schrage, D.P. Generating dynamic models including uncertainty for use in aircraft conceptual design
1997 AIAA Atmospheric Flight Mechanics Conference, New Orleans, LA, Collection of Technical Papers; UNITED STATES; 11-13 Aug. 1997, pp. 367-376 conference
Abstract: Accurate stability and control derivative information is essential to the configuration designer. As new, nonconventional aircraft are being designed, however, the trusted stability and control estimates usually used in conceptual design may no longer be useful. Using sophisticated analysis to compute every derivative in the highly iterative design environment is not a viable approach either. This paper proposes a method for addressing this dilemma by combining experimental design techniques for model building with vortex lattice aerodynamics for analysis. The careful implementation of this method results in parametric regression equations for three important derivatives as a function of the variables of most interest to the designer. These equations are based on actual analysis and not historical trends. Finally, uncertainty associated with this method is introduced and an initial technique for analyzing the effect of such uncertainty is presented. (Author)
@conference{DeLaurentis1997,
author = {Daniel A. DeLaurentis and Dimitri N. Mavris and Anthony J. Calise and Daniel P. Schrage},
title = {Generating dynamic models including uncertainty for use in aircraft conceptual design},
booktitle = {AIAA Atmospheric Flight Mechanics Conference, New Orleans, LA, Collection of Technical Papers; UNITED STATES; 11-13 Aug. 1997},
Conference: AIAA Atmospheric Flight Mechanics Conference, New Orleans, LA, Collection of Technical Papers; UNITED STATES; 11-13 Aug. 1997.
Other Numbers: A97-37244 10-08; Contract: NGT-10007.
Notes: Collection of Technical Papers (A97-37244 10-08).
Classification: 11 Aircraft (MT); 8 AIRCRAFT STABILITY AND CONTROL (AH).
DeLaurentis, D.A. & Mavris, E.G.D.N. Formulation of a Method to Assess Capacity Enhancing Technologies
2003 2003 AIAA/ICAS International Air and Space Symposium and Exposition: The Next 100 Years; Dayton, OH; July 14-17. conference
Abstract: The demand for air travel is expanding beyond the capacity of existing airports and air traffic control. This excess traffic often results in delays and compromised safety. Therefore, a number of initiatives to improve airport capacity and throughput have been proposed. However, in order to assess the impact of these technologies on commercial air traffic one must move beyond the vehicle to a system-of-systems point of view. This top-level perspective must include consideration of the aircraft, airports, air traffic management, and airlines that make up the airspace system. In addition to the analysis of each of these components and their interactions, a thorough investigation of capacity and throughput technologies requires due consideration of other pressures such as economics, safety, and government regulations. Furthermore, the air traffic system is inherently variable with constant changes in everything from fuel prices to the weather. Thus, the development of a modeling environment to be used in the evaluation of technological impacts while encompassing all these sources of uncertainty is the subject of this paper.
author = {Daniel A. DeLaurentis and Elena Garcia Dimitri N. Mavris},
title = {Formulation of a Method to Assess Capacity Enhancing Technologies},
booktitle = {2003 AIAA/ICAS International Air and Space Symposium and Exposition: The Next 100 Years; Dayton, OH; July 14-17.},
Conference: 2003 AIAA/ICAS International Air and Space Symposium and Exposition: The Next 100 Years; Dayton, OH; July 14-17, 2003.
Classification: 1 Aeronautics (General) (AH).
DeLaurentis, D., Kang, T., Lim, C., Mavris, D. & Schrage, D. System-of-systems modeling for personal air vehicles
Abstract: Ongoing research is described in this paper concerning the development of a methodology for adaptable system studies of future transportation solutions based upon personal air vehicles. Two challenges in this research are presented. The challenge of deriving requirements for revolutionary transportation concepts is a difficult one, due to the fact that future transportation system infrastructure and market economics are interrelated (and uncertain) parts of the equation. Thus, there is a need for a macroscopic transportation model, and such a task is well suited for the field of techniques known as system dynamics. The determination and visualization of the benefits of proposed personal air vehicle concepts for individuals presents a second challenge. In this paper, the primary benefit metrics that serve as system requirements for personal transportation applications are the Doorstep-to-Destination travel timesavings and net present value of utilizing the new transportation option as compared to a conventional transportation mode. The modeling and determination of these metrics, the synthesis of vehicle characteristics, as well as existing travel statistical data are integrated into the system model to enable visualization of the design space and to guide the design space evolution through sensitivity assessment. This individual traveler-based analysis is referred to as a microscopic model, and interesting results from its execution are reported. The results indicate the level and direction of technology progress required to create economically viable personal air transportation architectures. (Author)
@inproceedings{DeLaurentis2002a,
author = {DeLaurentis, Daniel and Kang, Taewoo and Lim, Choongiap and Mavris, Dimitri and Schrage, Daniel},
title = {System-of-systems modeling for personal air vehicles},
DeLaurentis, D. & Mavris, D.N. A new model for the aerospace design process based on a control system analogy
Abstract: A novel approach to the modeling and control of aerospace system design problems is presented. By integrating recent advances in probabilistic robust design and technology assessment methods with a traditional control system feedback architecture, the approach is intended to establish a unified structure for managing complex design problems under uncertainty. The notions of plant, state variables, feedback, and compensation are adapted from the realm of control theory to this new setting. A specific aspect of the paper addresses methods for categorizing and computing the plant's sensitivity to modeled uncertainty in the feedback system. An example problem is executed and described to illustrate probabilistic sensitivity analysis as well as one possible avenue for arriving at an optimal compensator. Since this topic is in the initial research stages, the near-term challenges with regards to refining and improving the approach are identified throughout the paper. Two such challenges include constructing a valid plant model and the optimal selection of a compensator. (Author)
author = {DeLaurentis, Daniel and Mavris, Dimitri N},
title = {A new model for the aerospace design process based on a control system analogy},
Classification: 11 Aircraft (MT); 63 CYBERNETICS (AH).
DeLaurentis, D., Mavris, D.N. & Schrage, D.P. System Synthesis in Preliminary Aircraft Design using Statistical Methods
1996 Congress of the International Council of the Aeronautical Sciences, Sorrento, Italy, 8-13 Sep. 1996 conference
Abstract: This paper documents an approach to conceptual and preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically design of experiments (DOE) and response surface methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. First, response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. Next, a regression equation for an overall evaluation criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in a innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting a solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of a high speed civil transport. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabalistic designs (and eventually robust ones). (Author)
author = {Daniel DeLaurentis and Dimitri N. Mavris and Daniel P. Schrage},
title = {System Synthesis in Preliminary Aircraft Design using Statistical Methods},
booktitle = {Congress of the International Council of the Aeronautical Sciences, Sorrento, Italy, 8-13 Sep. 1996},
Conference: UNITED STATES.
Report Number: NASA-CR-203326; NAS 1.26:203326; NIPS-97-09971.
Other Numbers: Contract: NAGW-4337; NAG2-900.
Notes: Presented at Congress of the International Council of the Aeronautical Sciences, Sorrento, Italy, 8-13 Sep. 1996; Available from CASI HC A03/MF A01.
Update: 1997u1.
Accession Number: N97-14883 (AH).
DeLaurentis, D., Pfaender, H., Mavris, D. & Schrage, D. A probabilistic methodology for the treatment of system-of-systems problems and application to future air transportation architectures
2002 ICAS 200223rd International Congress of Aeronautical Sciences conference
Abstract: In this paper, a problem is studied that extends the motives and goals of multi-"discipline" analysis and design to multi-"system" analysis and design. This transition is important since aerospace engineers and designers are increasingly being posed with "system-of-systems" type problems. Future aviation transportation concepts, future package delivery architectures, and future air-traffic management systems are three prime examples of such emerging system-of-systems. An extension to a novel methodology for conducting design trade-offs is presented, representing a critical part of the system engineering process. The new extension is probabilistic in nature and proceeds under the assumption that both requirement ambiguity and technology uncertainty play a key role in the early design exploration of system-of-systems problems. To simulate the interplay between requirements and technologies, a system-of-systems synthesis capability is needed, to serve in much the same capacity as sizing routines serve in aircraft design. System dynamics modeling, especially including causal loop analysis, is employed for this purpose by representing interaction mechanisms between heterogeneous systems. In this way, the sensitivities of overall system-of-systems responses to both system and intersystem architecture variables can be computed. After an introduction to the problem and a brief survey of related fields, a detailed description of key elements of a new system-of-systems conceptual design method is presented. An example application problem is introduced as the method is presented to further illustrate the approach. This problem involves the design of a package delivery architecture utilizing autonomous, vertical take-off and landing air vehicles.
author = {DeLaurentis, D. and Pfaender, H. and Mavris, D. and Schrage, D.},
title = {A probabilistic methodology for the treatment of system-of-systems problems and application to future air transportation architectures},
booktitle = {23rd International Congress of Aeronautical Sciences},
journal = {ICAS 2002},
publisher = {International Council of the Aeronautical Sciences, Verneuil-sur-Seine, 78480, France},
Conference: 23rd International Congress of Aeronautical Sciences; Proceedings; Toronto, Canada; Sep. 8-13, 2002.
Report Number: ICAS Paper 2002-111.1.
Notes: CD-ROM..
Publication Type: Journal Article.
DeLaurentis, Daniel Gagatay, E., Mavris, N, D. & Schrage, D. Methodology for future delivery architectures consisting of autonomous VTOL vehicles - A system-of-systems problem
2001 AIAA, Aircraft, Technology Integration, and Operations Forum, 1st, Los Angeles, CA; UNITED STATES; 16-18 Oct. 2001 conference
Abstract: Ideas are introduced that extend the motives and goals of multi-"discipline" analysis and design to multi-"system" analysis and design. This transition is important since aerospace engineers and designers are increasingly being posed with "system-of-systems" type problems. Future aviation transportation concepts, future package delivery architectures, and future air-traffic management systems are just three prime examples of such emerging system-of-systems. No longer confined to a focus on the aircraft as the totality of the system, designers need new theories, algorithms, and implementation tools to tackle this new class of problems. A system-of-systems synthesis capability is needed most urgently, to serve in much the same capacity as sizing routines serve in aircraft design. It is proposed in this paper that system dynamics modeling, especially including causal loop diagrams, can fulfill this purpose by representing information flow between heterogeneous systems. Further, individual systems (e.g. vehicles) within the global system can be represented either as contributing analyses or via metamodels. In this way, the sensitivities of overall system-of-systems responses to both vehicle and inter-system architecture variables can be computed. After an introduction to the problem and a brief survey of related fields, a detailed description of key elements of a new system-of-systems conceptual design method is presented. An example application problem is introduced as the method is presented to further illustrate the approach. This problem involves the design of a package delivery architecture utilizing autonomous, vertical flight-capable air vehicles. (Author)
author = {DeLaurentis, Daniel Gagatay, Erol and Mavris, and Dimitri N and Schrage, Daniel},
title = {Methodology for future delivery architectures consisting of autonomous VTOL vehicles - A system-of-systems problem},
DeLaurentis, D.M., N, D. & Schrage, D.P. System synthesis in preliminary aircraft design using statistical methods
Vol. 1ICAS, Congress, 20th, Naples, Italy, Proceedings; UNITED STATES; 8-13 Sept. 1996, pp. 866-878 conference
Abstract: This paper documents an approach to conceptual and early preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically, Design of Experiments (DOE) and Response Surface Methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. Response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. A regression equation for an overall evaluation criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in an innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting in solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of an HSCT. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabilistic designs (and eventually robust ones). (Author)
@conference{DeLaurentis1996c,
author = {DeLaurentis, Daniel Mavris, and Dimitri N and Schrage, Daniel P},
booktitle = {ICAS, Congress, 20th, Naples, Italy, Proceedings; UNITED STATES; 8-13 Sept. 1996},
Conference: ICAS, Congress, 20th, Naples, Italy, Proceedings. Vol. 1; UNITED STATES; 8-13 Sept. 1996.
Other Numbers: A96-40526 11-01; Contract: NAG2-900; NAGW-4337.
DeLaurentis, Daniel Mavris, D., N, Calise, A.J. & Schrage, D.P. Reduced order guidance methods and probabilistic techniques in addressing mission uncertainty
Abstract: This paper develops and describes analytical and statistical approximation techniques used to create design-oriented analyses which are implementable in the process. Specifically, techniques related to the vehicle guidance discipline are examined. The ultimate goal is to investigate the economic viability of an aerospace system in the face of uncertainty at the system and discipline design levels. The notion of a 'design mission' as a requirement is replaced by a modeling of mission variability, since future aircraft will likely fly a variety of missions. Aircraft guidance laws are key components in the mission analysis portion of an aircraft sizing code, and thus they must be included in the investigation. Through the use of statistical modeling techniques, a link between mission uncertainty, optimal guidance, wing planform, and economic objectives is obtained. This linkage allows for the investigation of guidance and mission effects on such quantities as gross weight and ticket price (on a per mile basis). Further, the resulting solutions are robust since they are obtained by choosing control parameters which maximize the probability of meeting a target while simultaneously assuring that appropriate constraints (which are also probabilistic) are met. (Author)
@conference{DeLaurentis1996b,
author = {DeLaurentis, Daniel Mavris, Dimitri and N and Calise, Anthony J and Schrage, Daniel P},
title = {Reduced order guidance methods and probabilistic techniques in addressing mission uncertainty},
Classification: 11 Aircraft (MT); 1 AERONAUTICS (GENERAL) (AH).
DeLaurentis, D.Z., S, P., Mavris, D. & Cesnik, Carlos E S; Schrage, D.P. New approaches to multidisciplinary synthesis - An aero-structures-control application using statistical techniques
1996 SAE and AIAA, World Aviation Congress, 1st, Los Angeles, CA; UNITED STATES; 21-24 Oct. 1996 conference
Abstract: An evolving aircraft synthesis simulation environment which offers improvements to existing methods at multiple levels of a design process is described. As design databases become obsolete due to the introduction of new technologies and classes of vehicles, and as sophisticated analysis codes are often too computationally expensive for iterative applications, the design engineer may find a lack of usable information needed for decision making. Within the environment developed in this paper, rapid sensitivity analysis is possible through a unique representation of the relationship between fundamental design variables and system objectives. The combined use of the Design of Experiments and Response Surface techniques provides the ability to form this design relationship among system variables and target values, which is termed design-oriented in nature. The use of design-oriented analysis in a design space search with potentially conflicting objectives is addressed by the use of a Decision Support Problem Technique, which casts the search in terms finding ranged sets of acceptable designs, as opposed to a traditional point design solution. Finally, a computing framework which facilitates the integration of the analysis with the design space search completes the simulation environment. The resulting product of this research is a case study demonstration: a supersonic transport flexible wing design problem involving the aerodynamics, structures, and controls disciplines. This particular problem is particularly challenging because of the complex interactions involved in its solution. Methods for overcoming these are highlighted. (Author)
@conference{DeLaurentis1996d,
author = {DeLaurentis, Daniel Zink, and P S and Mavris, Dimitri and Cesnik, Carlos E S; Schrage, Daniel P},
title = {New approaches to multidisciplinary synthesis - An aero-structures-control application using statistical techniques},
booktitle = {SAE and AIAA, World Aviation Congress, 1st, Los Angeles, CA; UNITED STATES; 21-24 Oct. 1996},
Conference: SAE and AIAA, World Aviation Congress, 1st, Los Angeles, CA; UNITED STATES; 21-24 Oct. 1996.
Report Number: SAE Paper 965501.
Other Numbers: Contract: NGT-51102L.
DeLaurentis, L.A. & Mavris, D.N. Uncertainty modeling and management in multidisciplinary analysis and synthesis
2000 AIAA, Aerospace Sciences Meeting and Exhibit, 38th, Reno, NV; UNITED STATES; 10-13 Jan. 2000 conference
Abstract: The complex, multidisciplinary nature of aerospace design problems, as well as the requirement to examine life-cycle characteristics, have exposed a need to model and manage uncertainty. In this paper, a formal approach for modeling uncertainty in such design problems is presented. The approach includes uncertainties associated with mathematical models, operation environment, response measurement, and input requirements. In addition, a new method for propagating this uncertainty (in an efficient manner) to find robust design solutions is developed and described. The uncertainty model, combined with the probabilistic robust design technique, is a critical advancement in multidisciplinary system design, in that it identifies solutions that have a maximum probability of success. Both the uncertainty model and robust design technique are demonstrated on an example problem involving the design of a supersonic transport aircraft using the relaxed static stability technology. At each step, validation studies are performed and initial results indicate that the robust design method represents an accurate depiction of the problem. This depiction provides critical insight into where and why uncertainty affects the family of design solutions. (Author)
author = {DeLaurentis, Laurent A and Mavris, Dimitri N},
title = {Uncertainty modeling and management in multidisciplinary analysis and synthesis},
booktitle = {AIAA, Aerospace Sciences Meeting and Exhibit, 38th, Reno, NV; UNITED STATES; 10-13 Jan. 2000},
Conference: AIAA, Aerospace Sciences Meeting and Exhibit, 38th, Reno, NV; UNITED STATES; 10-13 Jan. 2000.
Other Numbers: Contract: NGT-10007; NAG1-1793.
Fitzgerald, C.J., Weston, N.R., Putnam, Z.R. & Mavris, D.N. A conceptual design environment for technology selection and performance optimization for torpedoes
Abstract: The Torpedo Optimization, Analysis, and Design (TOAD) program is introduced as a parametric sizing and synthesis tool for torpedoes. Response surface methodology is introduced as a means for efficiently modeling the design space for torpedoes. Response surface equations are produced from the new thermal analysis section to model the design space for a Stored Chemical Energy Propulsion System (SCEPS) powered torpedo. Comparisons are made between SCEPS and electrically powered torpedoes, as well as between different SCEPS engine parameters. The design methods of the Aerospace Systems Design Laboratory (ASDL) are introduced for developing computationally efficient metamodels for the physics-based analysis codes used in design. Response surface methodology is shown to be an effective way to model a SCEPS powered torpedo. (Author)
@inproceedings{Fitzgerald2002,
author = {Fitzgerald, Caleb J and Weston, Neil R and Putnam, Zachary R and Mavris, Dimitri N},
title = {A conceptual design environment for technology selection and performance optimization for torpedoes},
Classification: 31 ENGINEERING (GENERAL) (AH).
Frits, A.P. & Mavris, D.N. Use of Probability of Success as an Independent Variable for Decision Making
Abstract: Early phases of design are characterized by risk and uncertainty. Appropriate accounting for this uncertainty is an important requirement for any designer. This work suggests collapsing risk and uncertainty into a single metric called the probability of success, which accounts for the probability of a given design simultaneously meeting all of the design requirements. Optimal or lowest cost designs can then be found for various levels of probability of success. These designs can be compared to each other, creating a trade-off between the cost of a design and its risk. These risk versus cost figures can be generated before a decision-maker commits to the design. Thus, the decision-maker will have all the information regarding the cost and risk of potential designs before making any design decisions. The decision-maker can thus treat the probability of success, or risk, as an independent variable, choosing the level of risk that he or she finds acceptable based upon the cost of the system, with the corresponding "optimal" design already determined. This paper illustrates a process to generate these risk versus cost curves for conceptual design, and gives two examples of the implementation of the process.
@conference{Frits2004,
author = {Frits, Andrew P and Mavris, Dimitri N},
title = {Use of Probability of Success as an Independent Variable for Decision Making},
Frits, A.P. & Mavris, D.N. A screening method for customizing designs around non-convergent regions of design spaces
Abstract: In engineering design, response surface methodology is often used to explore a design space and to generate a meta-model of the space. Designs of experiments are used in this process to obtain the most behavioral information from the space with the fewest number of runs. Often, the designer discovers that the analysis program cannot converge to an answer for one or more regions of the design space. Traditionally, the designer gets around this problem by shrinking the variable ranges so that there are no regions of non-convergence. Instead of this process, this paper suggests that it is better to treat the nonconvergent points as a region of infeasibility. Extra runs can be made to determine the border of this infeasible region, and then a custom design of experiments can be constructed to explore the design space while excluding the nonconvergent region. This process still generates a valid meta-model yet retains more of the design space than the simple reduction of variable ranges. (Author)
@inproceedings{Frits2002,
title = {A screening method for customizing designs around non-convergent regions of design spaces},
Classification: 61 COMPUTER PROGRAMMING AND SOFTWARE (AH).
Frits, A.R., Weston, K., Neil & Mavris, D. Benefits of non-dimensionalization in creation of designs of experiments for sizing torpedo systems
Abstract: Non-dimensionalization is useful at many stages in the conceptual design process. One area of usefulness is in the creation and execution of Design of Experiments. A Design of Experiments that is run with dimensional quantities can often have a large number of failed or infeasible cases or require frustratingly small ranges on the design variables in order to execute cleanly. However, with the use of non-dimensional parameters in the Design of Experiments, the dimensional values being used in the analysis tool automatically scale themselves so that appropriate magnitudes of each parameter are always being used. This automatic scaling greatly increases the stability of Design of Experiments when nondimensional parameters are used, limiting the number of failed cases. This paper explores potential non-dimensional parameters for use in the conceptual design of torpedo systems. The paper shows that traditional non-dimensional parameters used in propulsor design, such as advance ratio and thrust coefficient, also work well as torpedo design parameters. A short example is given where the performance of a Design of Experiments for a torpedo system is improved via the use of non-dimensional parameters.
@conference{Frits2004a,
author = {Frits, Andrew Reynolds, and Kristen Weston, and Neil and Mavris, Dimitri},
title = {Benefits of non-dimensionalization in creation of designs of experiments for sizing torpedo systems},
Frits, A.W., Neil & Mavris, D. Inclusion of tactical considerations for system-of-systems optimization of torpedoes
Abstract: In the current torpedo design process, torpedoes are often designed independently from the tactics with which they are employed. This serial design process, of first developing tactics, then designing the torpedo, then re-developing tactics leads to torpedo designs that are sub-optimal when viewed from the greater system-of-systems perspective. This paper looks at the effects that tactics have on the design of torpedoes. It proposes a new paradigm, of simultaneous tactics development and torpedo design, and looks at the implications of various tactics on the optimal design of torpedo systems.
@conference{Frits2004b,
author = {Frits, Andrew Weston, and Neil and Mavris, Dimitri},
title = {Inclusion of tactical considerations for system-of-systems optimization of torpedoes},
Frits, Andrew Weston, N.P., Mavris, C., N, D. & Kusmik, Aldo; Krol Jr, W. Examination of a torpedo performance space and its relation to the system design space
Abstract: In historical torpedo design, mission analysis, which relates torpedo performance to mission success, has been used as a stand-alone tool to derive specific torpedo performance requirements. These performance requirements must then be met by the torpedo designer. However, the incorporation of mission analysis into the engineering design of a torpedo system grants more freedom to the designer. The designer can immediately see the effects of design variable changes on mission success, and can infuse new tactics in addition to new technologies to expand the available design space. This paper serves to explore the performance space of a torpedo, and then relates this performance space to the design variables by mapping the performance space directly to the design space and design variables. The paper also studies how granting the designer control of weapon tactics expands the design space, allowing the torpedo and its tactics to be concurrently optimized. This new approach results in significantly greater design freedom and the ability to find a system-level global optimum. (Author)
@inproceedings{Frits2002a,
author = {Frits, Andrew Weston, Neil Pouchet, and and Colin Mavris, and Dimitri N and Kusmik, Aldo; Krol Jr, William},
title = {Examination of a torpedo performance space and its relation to the system design space},
German, B. & Mavris, D. Acoustic fluid compression and thermoacoustics - Enabling technologies for no-moving-parts aerospace propulsion?
2002 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Indianapolis, IN; UNITED STATES; 7-10 July 2002 inproceedings
Abstract: This paper surveys research in the areas of resonant nonlinear acoustics and thermoacoustics and suggests that these phenomena may hold applicability as propulsion system technologies. Potential cycle and engine system benefits include increased thermal efficiency and a reduction in mechanical complexity. Several notional applications, including pressure-rise combustors, pulse detonation engine enhancements, and MEMS propulsion devices, are suggested. The paper concludes with a description of some of the challenges facing development of these technologies. (Author)
@inproceedings{German2002a,
author = {German, Brian and Mavris, Dimitri},
title = {Acoustic fluid compression and thermoacoustics - Enabling technologies for no-moving-parts aerospace propulsion?},
booktitle = {38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Indianapolis, IN; UNITED STATES; 7-10 July 2002},
Conference: 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Indianapolis, IN; UNITED STATES; 7-10 July 2002.
Classification: 71 ACOUSTICS (AH).
German, B.J. & Mavris, D. Examination of time-averaged fluid compression driven by finite amplitude acoustics
Abstract: This paper presents a study of the effects of finite amplitude acoustic excitation on the resonant response within ducts. The emphasis is on time-averaged pressure and velocity. These time-averaged effects, termed radiation pressure and acoustic streaming, respectively, have been well known for many years. The nonlinear nature of the governing equations, however, has made detailed numerical studies difficult, especially for finite amplitude excitation. The approach employed in this study uses a frequency domain velocity potential model for the acoustic response based on a discrete number of harmonics. The time-averaged component is also considered. The equations are integrated numerically using a spectral collocation technique. Results are presented for cylindrical and conical geometries, and it is shown that finite amplitude excitation produces significant acoustic streaming within open-ended conical geometries and high time-averaged pressure in closed-end cones. These effects may show promise for certain propulsion system applications. (Author)
@inproceedings{German2002,
author = {German, Brian J and Mavris, Dimitri},
title = {Examination of time-averaged fluid compression driven by finite amplitude acoustics},
Graham, M. & Mavris, D.N. Implementation of parametric analysis to the aerodynamic design of a hypersonic strike fighter
Abstract: A hypersonic strike fighter (HSF) would provide many benefits over current fighters, including increased effectiveness and survivability. However, there are many design challenges to developing such a vehicle. Therefore, the conceptual design of an HSF requires the development of new tools and methods to analyze and select vehicle concepts. A parametric method was developed to determine aerodynamic characteristics of hypersonic vehicles in a rapid, automated way. This parametric method and other tools were then used to select a baseline design and optimize this baseline for the notional mission. (Author)
@conference{Graham2000,
author = {Graham, Matthew and Mavris, Dimitri N},
title = {Implementation of parametric analysis to the aerodynamic design of a hypersonic strike fighter},
Hale, M.A. & Mavris, D.N. Enabling advanced design methods in an Internet-capable framework
1999 AIAA and SAE, 1999 World Aviation Conference, San Francisco, CA; UNITED STATES; 19-21 Oct. 1999 inproceedings
Abstract: The enabling of advanced design methods in an Internet-capable framework is discussed. The resulting framework represents the next generation of design and analysis capability in which engineering decision-making can be done by geographically distributed team members. A new Internet technology called the lean-server approach is introduced as a mechanism for granting Web browser access to frameworks and domain analyses. This approach has the underpinnings required to support these next-generation frameworks: collaboratories. A historical perspective of design frameworks is discussed to provide an understanding of the design functionality that is expected from framework implementations to insure design technology advancement. Two research areas were identified as being important to the development of collaboratories: design portals and collaborative methods. An Internet-enabled design framework called IMAGE is highlighted and demonstrated using a probabilistic design example. The prototyped methods have found their way into a Conceptual Aerospace Systems Design and Analysis Toolkit used by the Air Force Research Laboratory. (Author)
@inproceedings{Hale1999,
author = {Hale, Mark A and Mavris, Dimitri N},
title = {Enabling advanced design methods in an Internet-capable framework},
Other Numbers: Contract: F33615-95-D-3800; N00014-91-1-0783; NAG1-1786.
Hale, M.A., Mavris, D.N. & Carter, D.L. The implementation of a Conceptual Aerospace Systems Design and Analysis Toolkit
Abstract: The Conceptual Aerospace Systems Design and Analysis Toolkit (CASDAT) provides a baseline assessment capability for the Air Force Research Laboratory. The historical development of CASDAT is of benefit to the design research community because considerable effort was expended in the classification of the analysis tools. Its implementation proves to also be of importance because of the definition of assessment use cases. As a result, CASDAT is compatible with accepted analysis tools and can be used with state-of-the-art assessment methods, including technology forecasting and probabilistic design. (Author)
@conference{Hale1999a,
author = {Hale, Mark A and Mavris, Dimitri N and Carter, Dennis L},
title = {The implementation of a Conceptual Aerospace Systems Design and Analysis Toolkit},
Other Numbers: Contract: F33615-95-D-3800.
Classification: 11 Aircraft (MT); 61 COMPUTER PROGRAMMING AND SOFTWARE (AH).
Hines, N.R. & Mavris, D.N. A parametric design environment for including signatures analysis in conceptual design
Abstract: System effectiveness has become the prime metric for the evaluation of military aircraft. As such, it is the designer's goal to maximize system effectiveness. Industry documents indicate that all future military aircraft will incorporate signature reduction as an attempt to improve system effectiveness. Today's operating environments demand low observable aircraft that are able to reliably eliminate valuable, time critical targets. Thus, it is desirable to be able to evaluate the signatures of a vehicle, as well as the influence of signatures on the systems effectiveness of a vehicle. Previous studies have shown that shaping of the vehicle is one of the most important contributors to radar cross section and must be considered from the very beginning of the design process. This research strives to meet these needs by developing a parametric geometry radar cross section prediction tool. This tool is envisioned to predict the radar cross section of the vehicle as well as the impact of geometry changes. (Author)
@conference{Hines2000,
author = {Hines, Nathan R and Mavris, Dimitri N},
title = {A parametric design environment for including signatures analysis in conceptual design},
Hollingsworth, P. & Mavris, D. Gaussian Process Meta-Modeling - Comparison of Gaussian Process Training Methods
Abstract: A Gaussian process is a non-linear, Bayesian-based data fitting method. The ability of Gaussian processes to flexibly and accurately fit arbitrary, even highly nonlinear, data sets has led to considerable interest in their application to a number of areas. This paper examines the usefulness of Gaussian process models for application to complex systems design. In particular, several approaches to training Gaussian process models are examined. The results of these training methods are compared for several example problems, and guidance is provided regarding the best training method for a particular situation.
@conference{Hollingsworth2003,
author = {Hollingsworth, Peter and Mavris, Dimitri},
title = {Gaussian Process Meta-Modeling - Comparison of Gaussian Process Training Methods},
Classification: 65 Statistics and Probability (AH).
Hollingsworth, P. & Mavris, D.N. A method for concept exploration of hypersonic vehicles in the presence of open and evolving requirements
Abstract: Several unique aspects of the design of hypersonic aerospace systems necessitate a truly multidisciplinary approach from the outset of the program. These, coupled with a vague or changing requirements environment, provide an impetus for the development of a systematic and unified approach for the exploration and evaluation of alternative hypersonic vehicle concepts. The method formulated and outlined in this paper is founded upon nondeterministic conceptual and preliminary design formulations introduced over the past decade and introduces the concept of viewing system level requirements in a similar manner. The proposed method is then implemented for the concept exploration and design of a Hypersonic Strike Fighter in the presence of ambiguous open and/or evolving requirements. (Author)
author = {Hollingsworth, Peter and Mavris, Dimitri N},
title = {A method for concept exploration of hypersonic vehicles in the presence of open and evolving requirements},
Hollingsworth, P.M. & Mavris, D.N. Determination of revolutionary requirements boundaries for a high-speed, airbreathing propulsion system
Abstract: Modern propulsion system design and selection for future air-vehicle systems is an inherently uncertain process. The long lead-times in the development of new propulsion systems produce significant levels amount of risk for the propulsion system manufacturer. Additionally, this long lead-time allows a tremendous amount of program inertia to build up as the development process progresses. This inertia prohibits the propulsion system manufacturer from reacting to 'catastrophic' changes in the system requirements. It can be shown that there exist certain regions in the system requirements hyperspace where a small change in a given requirement or requirements requires a completely different solution. Additionally, because of the inherent security associated with evolving current designs; there exists in the engineering community a reluctance to develop truly new and revolutionary technologies and systems. Therefore it is of interest to develop a method by which the location of catastrophic boundaries can be discerned. The method chosen to investigate the requirements hyperspace for supersonic cruise propulsion systems is a genetic algorithm (GA). The GA was used to determine both individual and combined technology limit boundaries and to determine the effect of technology infusion on these boundaries. (Author)
@inproceedings{Hollingsworth2002,
author = {Hollingsworth, Peter M and Mavris, Dimitri N},
title = {Determination of revolutionary requirements boundaries for a high-speed, airbreathing propulsion system},
Classification: 7 AIRCRAFT PROPULSION AND POWER (AH).
Hong, C.H., Cheplak, M., Choi, J.-Y. & Mavris, D.N. Flexible Multi-Body Design of a Morphing UCAV
2004 AIAA 3rd "Unmanned Unlimited" Technical Conference, Workshop and Exhibit; Chicago, IL; USA; 20-23 Sept. 2004, pp. 1-11 conference
Abstract: During the first Gulf War a major effort was carried out to find and destroy Iraqi Scud missiles. The McDonnell Douglas F-15E aircraft carried out the Scud hunting operation, which included a hunter and killer phase. This Scud hunting mission was not successful due to lack of evidence of any Scuds actually being destroyed. The endurance of the F-15E is sufficient for an attack aircraft, but not long enough for such a search and destroy mission. Even with mid-air refueling, the flight time is limited by the fatigue of the pilot. The high endurance of Northrop Grumman's Global Hawk Unmanned Aerial Vehicle (UAV) along with a high-speed attack capability and sensors to identify Scud missiles is the key goal. The challenges of an Unmanned Combat Aerial Vehicle (UCAV) successfully meeting the requirements of both a low-speed, high-altitude loiter and a supersonic strike capable aircraft dictates a concept that requires significant geometric morphing. This resulted in a desired wing area change of 200%, a sweep angle change from 20 to 70 degrees, and an aspect ratio change from 3 to 7. The structural design challenges and solutions are presented that would satisfy such a requirement. The conceptual design model involves that of a coplanar joined wing, which used revolute and spherical joints to enable the necessary configuration change. Areas of concern included the amount of weight penalty involved with the addition of the joints and whether or not this weight penalty would be overcome by the benefit in fuel efficiency. Existing variable sweep wing aircraft that utilized joint mechanisms were researched to provide starting points for a morphing mechanism. The finite element based flexible multi-body analysis tool, DYMORE, was used to investigate joint loads and multi-body behavior for various configurations. Two models were tested, one which included only revolute joints, and the other included a combination of revolute and spherical joints. Joint materials were researched to reduce the weight and maximize strength of the mechanism as much as possible. The drop test simulation results, which was the most critical scenario, were used to size the joints via simple mechanics of materials assumptions. A modal analysis was performed as well to investigate the natural frequencies and critical modes that the aircraft would experience due to the significant geometrical change. The fact that the morphing combat aircraft is unmanned allows flexibility in pushing the envelope and increases the chance of success with such an exotic aircraft design.
@conference{Hong2004,
author = {Hong, Chul Hwa and Cheplak, Matthew and Choi, Jou-Young and Mavris, Dimitri N},
title = {Flexible Multi-Body Design of a Morphing UCAV},
booktitle = {AIAA 3rd "Unmanned Unlimited" Technical Conference, Workshop and Exhibit; Chicago, IL; USA; 20-23 Sept. 2004},
Conference: AIAA 3rd "Unmanned Unlimited" Technical Conference, Workshop and Exhibit; Chicago, IL; USA; 20-23 Sept. 2004.
Jimeno, J. & Mavris, D.N. An automated robust process for physics base aerodynamic prediction
Abstract: By combining the response surface methodology with a classical design of experiments formulation, a robust method was developed to facilitate the aerodynamic analysis of conceptual designs. These aerodynamic predictions, presented in a parametric form, can then be furnished to a sizing and synthesis code for further evaluation of the concept at the system level. The computational basis of this methodology is a set of numerical codes that work in unison to both optimize the geometry for minimal drag and evaluate key aerodynamic parameters, such as lift, friction, wave, and induced drag coefficients. Code fidelity and sensitivity to a wide variety of input parameters, such as aircraft geometry, panel layout, number of panels used, and flow theory used within the numerical code, was investigated. The numerical results were compared with experimental data for different configurations, and the code-input parameters required for the best correlation were grouped according to aircraft type. These input parameters could later be used to analyze new designs that fall within an identified aircraft type. The resulting numerical predictions should then have the smallest possible error. Comparing numerical predictions of each group with the experimental data provided an estimate of the error at discrete points. The error data were later fitted with a continuous Chebyshev polynomial. (Author)
@conference{Jimeno2000,
author = {Jimeno, Jesus and Mavris, Dimitri N},
title = {An automated robust process for physics base aerodynamic prediction},
Kim, H.-S., Mavris, D., Virasak, J. & Schrage, D.P. Selection and design optimization of a high speed, highly maneuverable rotorcraft configuration
Vol. 2AHS, Annual Forum, 51st, Fort Worth, TX, Proceedings; UNITED STATES; 9-11 May 1995, pp. 1283-1300 conference
Abstract: Well documented parameter design optimization methods such as the Design of Experiments (DOEs) technique have been extensively used throughout the automotive and aerospace industry for on or off-line process control. The Center of Excellence in Rotorcraft Technology (CERT) at Georgia Tech has recognized the importance of these methods in the early design phases, where their impact can be felt the most, and is in the process of incorporating them to form an Integrated Product and Process Design (IPPD) environment. This paper describes the above mentioned technique and describes its implementation to the design of a coaxial compound helicopter. The concept formulation was driven by a set of stringent maneuverability requirements obtained from the 1992 AHS student design competition. The objective of this paper is to demonstrate the DOE methodology, to identify the key design variables, and to show how these design variables affect either the economics or the performance characteristics of this aircraft. This task is achieved through the formulation of a simplified Response Surface Method equation that captures the essence of the sizing/economics code as a function of the most significant design variables. This paper shows how to optimize a given configuration based on this approach, and illustrates how a 'better' solution can be obtained compared to the one determined by the traditional parametric approach. (Author)
@conference{Kim1995,
author = {Kim, Ho-Sik and Mavris, Dimitri and Virasak, Jacques and Schrage, Daniel P},
title = {Selection and design optimization of a high speed, highly maneuverable rotorcraft configuration},
booktitle = {AHS, Annual Forum, 51st, Fort Worth, TX, Proceedings; UNITED STATES; 9-11 May 1995},
Conference: AHS, Annual Forum, 51st, Fort Worth, TX, Proceedings. Vol. 2; UNITED STATES; 9-11 May 1995.
Kim, H.-S.S., P, D. & Mavris, D.N. Conceptual design optimization for military helicopter maneuverability and agility
Vol. 1AHS, Annual Forum, 53rd, Virginia Beach, Proceedings; UNITED STATES; Apr. 29-May 1 1997, pp. 775-782 conference
Abstract: This study discusses the specific helicopter maneuvers which are performed in aerial encounters and the performance and handling qualities characteristics which influence maneuverability and agility. This study was accomplished by a unique approach to conceptual and early preliminary aircraft design in which system synthesis and optimization are achieved using statistical methods, specifically Design of Experiments (DOE) and Response Surface Methodology (RSM), in order to more efficiently search the design space for optimum configurations. The objective is to develop a new approach to integrate rotorcraft maneuverability and agility into a generic conceptual design using an Integrated Product /Process Development (IPPD) methodology to determine how maneuverability and agility attributes can be designed from the conceptual phase. This task is achieved through the integration of design synthesis codes and analysis codes, and the formulation of simplified Response Surface Equations that capture the essence of the code as a function of the most significant design variables. (Author)
author = {Kim, Ho-Sik Schrage, and Daniel P and Mavris, Dimitri N},
title = {Conceptual design optimization for military helicopter maneuverability and agility},
booktitle = {AHS, Annual Forum, 53rd, Virginia Beach, Proceedings; UNITED STATES; Apr. 29-May 1 1997},
Conference: AHS, Annual Forum, 53rd, Virginia Beach, Proceedings. Vol. 1; UNITED STATES; Apr. 29-May 1 1997.
Kirby, M.R. & Mavris, D.N. An approach for the intelligent assessment of future technology portfolios
2002 AIAA Aerospace Sciences Meeting & Exhibit, 40th, Reno, NV; UNITED STATES; 14-17 Jan. 2002 inproceedings
Abstract: A solid business case is highly dependent upon a strategic and intelligent technology research and development plan, or portfolio, in the early phases of product design. The embodiment of a strategic technology development plan is the identification and subsequent funding of high-payoff technology areas that can maximize a company's return on investment, which entails both performance and economic objectives. This paper describes an approach whereby the high- payoff technology areas may be identified to quantitatively justify resource allocation decisions and investment opportunities to meet future organizational goals. The approach includes the simulation of the impact of generic technology areas and the degree of difficulty of technological advances within said areas. The approach results in a dynamic forecasting environment whereby rapid tradeoffs can be performed in the conceptual phases of design. This environment allows for intelligently building a successful technology portfolio to facilitate a quantitative justification of a solid business case. A proof-on-concept application was performed on a next-generation supersonic transport. (Author)
@inproceedings{Kirby2002,
author = {Kirby, M R and Mavris, D N},
title = {An approach for the intelligent assessment of future technology portfolios},
booktitle = {AIAA Aerospace Sciences Meeting & Exhibit, 40th, Reno, NV; UNITED STATES; 14-17 Jan. 2002},
Conference: AIAA Aerospace Sciences Meeting & Exhibit, 40th, Reno, NV; UNITED STATES; 14-17 Jan. 2002.
Classification: 81 ADMINISTRATION AND MANAGEMENT (AH).
Kirby, M.R. & Mavris, D.N. A method for technology selection based on benefit, available schedule and budget resources
Abstract: The accepted paradigm in aerospace systems design was to design systems sequentially and iteratively to maximize performance based on minimum weight. The traditional paradigm does not work in the rapidly changing global environment. A paradigm shift from the norm of 'design for performance' to 'design for affordability and quality' has been occurring in recent decades to respond to the changing global environment. Observations were made regarding new tenets needed to bridge the gap from the old to the new. These tenets include new methods and techniques for designing complex systems due to uncertainty and multidimensionality, consideration of the life cycle of the system, and the methods needed to assess breakthrough technologies to meet aggressive goals of the future. The Technology Identification, Evaluation, and Selection method was proposed as a possible solution to the paradigm shift. In particular, refinements of selection approaches were presented and included scoring models, technology frontiers, and resource allocation. Each of the approaches provided a different viewpoint of the same problem of selecting the best mix of technologies to maximize customer satisfaction. The new elements of the selection step were applied to a High Speed Civil Transport concept. This concept was chosen due to the technically challenging customer requirements and the need for breakthrough technologies over present capabilities. The new selection approaches deemed three technologies worthy of scarce resource monies for further development and include composite fuselage structures, hybrid laminar flow control, and advanced flight deck systems, such as synthetic vision. (Author)
@conference{Kirby2000,
author = {Kirby, Michelle R and Mavris, Dimitri N},
title = {A method for technology selection based on benefit, available schedule and budget resources},
Classification: 22 Bridges and Tunnels (CE); 11 Aircraft (MT); 31 ENGINEERING (GENERAL) (AH).
Subfile: Civil Engineering (CE); Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH).
Kirby, M.R. & Mavris, D.N. Forecasting technology uncertainty in preliminary aircraft design
Abstract: An evolved version of the Technology Identification, Evaluation, and Selection (TIES) method is presented that provides techniques for quantifying technological uncertainty associated with immature technologies. Uncertainty in this context implies forecasting. Forecasting the impact of immature technologies on a system is needed to provide increased knowledge to a decision-maker in the conceptual and preliminary phases of aircraft design. The increased knowledge allows proper allocation of company resources and program management. The TIES method addresses the milestones encountered during a technology development program, the sources of uncertainty during that development, a potential method for bounding and forecasting the uncertainty, and a means to quantify the impact of any emerging technology. A proof of concept application was performed on a High Speed Civil Transport concept due to its technically challenging customer requirements. (Author)
title = {Forecasting technology uncertainty in preliminary aircraft design},
Other Numbers: Contract: N00014-97-1-0783; NAG1-1793.
Kirby, M.R., Mavris, D.N. & Largent, M.C. A process for tracking and assessing emerging technology development programs for resource allocation
2001 AIAA, Aircraft, Technology Integration, and Operations Forum, 1st, Los Angeles, CA; UNITED STATES; 16-18 Oct. 2001 inproceedings
Abstract: This paper discusses a quantitative process to track the progress of technology developments within an organizational structure. The process accounts for the temporal aspects of technology development programs such that technology portfolio assessments, in the form of technological progress towards organizational goals, may be monitored and assessed. Progress tracking of internal R&D programs is an essential element to successful strategic endeavors and justification of the pursuit of capital projects. The process discussed herein incorporates traditional methods for technology portfolio assessments with an amalgamation of quantitative assessments (tracking) and qualitative information (monitoring) while utilizing various modern design techniques, and is called the Technology Metric Assessment and Tracking process. Application of this process would provide a quantitative technology portfolio assessment to substantiate a company's strategic investment plan over the life of various product design cycles such that the maximum payoff of technology investments may be pursued and the associated risks monitored. (Author)
author = {Kirby, Michelle R and Mavris, Dimitri N and Largent, Matthew C},
title = {A process for tracking and assessing emerging technology development programs for resource allocation},
Other Numbers: Contract: NAS3-00179.
Koch, P.N., Mavris, D. & Mistree, F. Partitioned, multilevel response surfaces for modeling complex systems
Vol. 38(5)Collection of Technical Papers. Pt. 3, AIAA Journal (0001-1452), pp. 1954-1968,875-881 conference
Abstract: The most prevalent type of approximating functions employed for efficient engineering analysis and design integration are polynomial response surfaces. However, the construction of response surface approximations has been limited to problems with only a few variables, due to the number of analyses necessary to fit sufficiently accurate models. An approach is presented for partitioning response surfaces and constructing multilevel approximations for problems with larger numbers of variables. Using this approach, the (computer) experimentation necessary for fitting response surface models is reduced tremendously. A modified composite experimental design is also presented for the construction of response models that provide more consistently accurate predictions across the range of the design variables. The multilevel, partitioned response surface modeling and modified composite design approaches are demonstrated for the preliminary design of a commercial turbofan engine. (Author)
@conference{Koch2000,
author = {Koch, Patrick N and Mavris, Dimitri and Mistree, Farrokh},
title = {Partitioned, multilevel response surfaces for modeling complex systems},
booktitle = {Collection of Technical Papers. Pt. 3, AIAA Journal (0001-1452)},
pages = {1954-1968,875-881},
Other Numbers: Contract: NSF DMI-96-12365.
Classification: 63 Mathematics and Computation (CE); 12 Spacecraft (MT); 64 NUMERICAL ANALYSIS (AH).
Koch, P.N., Mavris, D. & Mistree, F. Multi-level, partitioned response surfaces for modeling complex systems
Abstract: An approach is presented for partitioning response surfaces and constructing multilevel approximations for problems with larger numbers of variables. Using this approach, the (computer) experimentation necessary for fitting response surface models is reduced tremendously. A modified composite experimental design is also presented for the construction of response models that are more consistently accurate across the range of the design variables. The multilevel, partitioned response surface modeling and modified composite design approaches are demonstrated for the preliminary design of a commercial turbofan engine, an example problem defined in collaboration with Allison Engine Company, Rolls-Royce Aerospace Group. (Author)
title = {Multi-level, partitioned response surfaces for modeling complex systems},
Classification: 64 NUMERICAL ANALYSIS (AH).
Komerath, N., Mavris, D. & Liou, S. Prediction of unsteady pressure and velocity over a rotorcraft in forward flight
Vol. 28Journal of Aircraft, pp. 509-516 conference
@conference{KOMERATH1991,
author = {N.M. Komerath and D.N. Mavris and S.G. Liou},
title = {Prediction of unsteady pressure and velocity over a rotorcraft in forward flight},
booktitle = {Journal of Aircraft},
Conference: AIAA, Fluid Dynamics, Plasma Dynamics and Lasers Conference, 20th, Buffalo, NY; UNITED STATES; 12-14 June 1989.
Other Numbers: Contract: DAAL03-88-K-0070.
Notes: Previously cited in issue 18, p. 2756, Accession no. A89-42072.
Classification: 2 AERODYNAMICS (AH).
Komerath, N., Mcmahon, H., Brand, A., Liou, S.-G. & Mavris, D. Prediction and measurement of the aerodynamic interactions between a rotor and airframe in forward flight
1989 AHS, Annual Forum, 45th, Boston, MA; UNITED STATES; 22-24 May 1989- 335, pp. 323 conference
Abstract: Results of a detailed study of aerodynamic interactions are summarized. The test case is a two-bladed, rigid teetering rotor above a hemisphere- cylinder airframe in low-speed forward flight. A multi-faceted set of measurements, including surface pressures, thrust, flow velocity, and vortex trajectories has been acquired and used to develop and validate a potential-flow method to predict such interactions. The salient features of the measurements and the prediction method are summarized. The test case shows strong interaction effects. The interaction problem is seen to be dominated by unsteady, but mostly periodic, effects. The potential flow method is seen to be capable of predicting the dominant features of the interaction, in an azimuth-resolved fashion, under these conditions. However, it is inadequate to explain the details of the interaction of the strong vortices from the rotor with the airframe surface. (Author)
author = {Narayanan Komerath and Howard Mcmahon and Albert Brand and Shiuh-Guang Liou and Dimitri Mavris},
title = {Prediction and measurement of the aerodynamic interactions between a rotor and airframe in forward flight},
booktitle = {AHS, Annual Forum, 45th, Boston, MA; UNITED STATES; 22-24 May 1989- 335},
publisher = {Alexandria, VA, American Helicopter Society},
pages = {323},
Conference: AHS, Annual Forum, 45th, Boston, MA; UNITED STATES; 22-24 May 1989.
Other Numbers: Contract: DAAG29-82-K-0084; A90- 28151 11-01.
Notes: Proceedings.
Kopra, T.L., Mavris, D.N., Gomez, P.M. & Schrage, D.P. Application of a concurrent engineering methodology to the design of a dual use VTOL aircraft
Abstract: The Dual Use VTOL aircraft is a proposed passenger aircraft capable of rapidly transporting passengers and cargo to destinations 500 nautical miles apart in support of civilian and military requirements. This paper outlines how the Georgia Tech Concurrent Engineering methodology was implemented to assist in formalizing the design process from concept inception to configuration selection and optimization. Methods and tools, such as Quality Function Deployment (QFD) and functional analysis, were used to simplify the identification of the customers' needs and to allow their prioritization based on quantifiable engineering performance measures. Once the problem was defined and the value objectives were established, three feasible VTOL aircraft configurations were selected. These concepts were then evaluated using a simplified fuel balance vehicle sizing method and a criterion function that captures economic, performance, and utilization concerns. A parameter design optimization method was used to select the Dual Use VTOL aircraft, yielding the tilt rotor as the most viable configuration. (Author)
@conference{Kopra1994,
author = {Kopra, Timothy L and Mavris, Dimitri N and Gomez, Patrick M and Schrage, Daniel P},
title = {Application of a concurrent engineering methodology to the design of a dual use VTOL aircraft},
Kumpel, A.E., Barros Jr, P.A., Burg, C.M. & Villeneuve, Frederic J; Mavris, D.N. A conceptual design for the space launch capability of the Peacekeeper ICBM
Abstract: This paper presents the results of the concept selection, refinement, and verification phases of the conceptual design for the space launch capability of the Peacekeeper Intercontinental Ballistic Missile (ICBM). The redesigned Peacekeeper Space Launch Vehicle (SLV) is intended to serve primarily as a rapid resupply system for the International Space Station (ISS). Using quality engineering techniques, many potential configurations were determined and evaluated based on: performance, cost, availability, reliability, and safety; commonality with existing space systems; and compatibility with various launch sites. A single concept and its subsystems were selected. Various alternatives for ISS mating; payload module and shroud design; solid rocket boosters; and guidance, navigation and control systems were examined and chosen. This design of the Peacekeeper SLV was verified probabilistically through a trajectory and orbit transfer analysis, as well as a trajectory optimization tool. Finally, the logistics and costs associated with the Peacekeeper SLV program were assessed. (Author)
@inproceedings{Kumpel2002,
author = {Kumpel, Amy E and Barros Jr, Peter A and Burg, Cecile M and Villeneuve, Frederic J; Mavris, Dimitri N},
title = {A conceptual design for the space launch capability of the Peacekeeper ICBM},
Classification: 15 LAUNCH VEHICLES AND SPACE VEHICLES (AH).
Laps, Tobias Burdun, I., Y, Mavris, D.N. & Schrage, D.P. Method for the exploration of cause and effect links and derivation of causal trees from accident reports
1999 Advances in Aviation Safety Conference and Exposition, Daytona Beach, FL; UNITED STATES; 13-15 Apr. 1999, pp. 89-102 conference
Abstract: The ultimate goal of knowledge-based aircraft design, pilot training and flight operations is to make flight safety an inherent feature of the flight vehicle. Individual flight accidents and incidents may vary in terms of quantitative characteristics, circumstances, and other external details. However, their cause-and-effect patterns often reveal invariant structure or essential causal chains which may recur in the future for the same or other vehicle types. The identification of invariant logical patterns from flight accident reports, time-histories and other data sources is very important for enhancing flight safety at the level of the 'pilot vehicle-operational conditions' system. The objective of this research project was to develop and assess a method for 'mining' knowledge of typical cause-and-effect patterns from flight accidents and incidents. (Author)
@conference{Laps1999,
author = {Laps, Tobias Burdun, Ivan and Y and Mavris, Dimitri N and Schrage, Daniel P},
title = {Method for the exploration of cause and effect links and derivation of causal trees from accident reports},
booktitle = {Advances in Aviation Safety Conference and Exposition, Daytona Beach, FL; UNITED STATES; 13-15 Apr. 1999},
publisher = {Warrendale, PA: Society of Automotive Engineers, Inc. (SAE P-343)},
Conference: Advances in Aviation Safety Conference and Exposition, Daytona Beach, FL; UNITED STATES; 13-15 Apr. 1999.
Report Number: SAE Paper 1999-01-1433.
Notes: Proceedings (A99-32246 08-03).
Classification: 3 AIR TRANSPORTATION AND SAFETY (AH).
Largent, M.C. & Mavris, D.N. Probabilistic modeling of technology development for use in project planning and management
Abstract: From the dawn of human flight, the use of new technology has been necessary for aircraft to fly faster, further, and higher. That need continues today, making technology development a critical factor in new aerospace systems development. This study introduces some of the detailed formulation behind a process developed to assist the planning and management of a development project for a new technology. The process is based on risk management and uses probabilistic analysis, project network techniques, and Bayesian statistics in order to provide information useful for decision-making. The six steps in the process focus on identification and reduction of performance uncertainty, as well as identification of cost and schedule risk and uncertainty. The process introduces some ways in which analysis can interact with expert opinion in order to produce meaningful system-level comparisons of technologies. The iterative nature of the process helps to deal with uncertainty in the technology and outside influences that affect the technology's development. (Author)
@inproceedings{Largent2002,
author = {Largent, Matthew C and Mavris, Dimitri N},
title = {Probabilistic modeling of technology development for use in project planning and management},
Largent, M.C. & Mavris, D.N. Formulation of a process for the planning and management of technology development
Abstract: Due to the importance of technology use in aerospace systems, the process of technology development is one of the most important parts of fielding a new system. Technology development is the process of creating-and managing activities, such as experiments, analysis, and prototyping, in order to reduce the risk associated with the use of a new technology. While technical risk is addressed by the activities, the project must be planned and managed so as to reduce the cost and schedule risk associated with completing those activities. This study introduces a process that will assist in the planning and management of a technology development project and lead to successful development efforts. (Author)
@conference{Largent2001,
title = {Formulation of a process for the planning and management of technology development},
Classification: 80 Management and Marketing (MT); 81 ADMINISTRATION AND MANAGEMENT (AH).
Lee, J., Jeong, H., Volovoi, V. & Mavris, D. BPN Based Constrained Meta-Models for Approximate Optimization of Composite Rotor Blades
2006 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Newport, RI; USA; 1-4 May 2006, pp. 1-11 conference
Abstract: Back-propagation neural networks (BPN) have been extensively used as global approximation tools in the context of approximate optimization. A traditional BPN is trained by minimizing the absolute difference between target outputs and approximate outputs, thereby resulting in approximate optimal solutions being sometimes actually infeasible when it is used as a meta-model for inequality constraint functions. The paper explores the development of the efficient BPN based meta-model that ensures the constraint feasibility of approximate optimal solution. The BPN based meta-model is optimized via exterior penalty method to optimally determine interconnection weights between layers in the network. The verification of the proposed approach is examined through ten-bar truss and composite rotor blade problems. For constrained approximate optimization, design of suspension with optical flying head is conducted to enhance the shock resistance capability in addition to dynamic characteristics.
@conference{Lee2006,
author = {Lee, J and Jeong, H and Volovoi, V and Mavris, D},
title = {BPN Based Constrained Meta-Models for Approximate Optimization of Composite Rotor Blades},
booktitle = {47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Newport, RI; USA; 1-4 May 2006},
Conference: 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Newport, RI; USA; 1-4 May 2006.
Classification: C1 Mechanical Properties (ED); 61 Design Principles (MT); 37 Mechanical Engineering (AH); 15 Engineering and Industry (SO).
Accession Number: 200606-C1-D-12093 (ED); 200606-61-34972 (MT); A06-37-24701 (AH); 200606-15-34804 (SO).
Subfile: Engineered Materials: Composites (ED); Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH); Solid State & Superconductivity (SO).}
Lee, J., Mavris, D. & Schrage, D. Probabilistic inverse aerodynamic design and stability analysis response surface methodology for natural laminar flow wings from an aircraft system design point of view
2003 21st AIAA Applied Aerodynamics Conference; Orlando, FL; June 23-26. conference
Abstract: Skin friction drag and induced drag together account for more than 80 percent of the total drag of current subsonic aircraft. A new probabilistic Natural Laminar Flow (NLF) wing design methodology has been established to minimize these two important sources of drag. Using this method, a synthesis and sizing code is used to estimate the benefits of NLF technology at the system level, and to determine optimal wing planform geometry and wing area for a given set of mission requirements. The chordwise pressure distribution of the optimized NLF wing planform from the sizing code is then parameterized carefully on the basis of physical insights. An inverse aerodynamic design technique is then used to find the corresponding airfoil geometry for a given pressure distribution. A metamodel building method called Response Surface Methodology (RSM) is then used to minimize the total drag of the wing at the design cruise condition given by the sizing code, with respect to the design parameters chosen. In this procedure, the accurate prediction of the onset of laminar-to-turbulent transition is crucial to estimate the skin friction drag. A reasonable approximation is achieved by initially computing the mean flow by means of a Navier-Stokes code, CFL3D, followed by a compressible linear stability analysis code, COSAL3D, to estimate transition location and, finally, CFL3D is executed again. At this time, a turbulence model is applied after the predicted transition point for a more accurate skin friction drag prediction. Finally, to account for the uncertainty of the prediction of the transition location, a Monte Carlo simulation is performed through the use of response surface equations.
author = {Lee, Jae and Mavris, Dimitri and Schrage, Daniel},
title = {Probabilistic inverse aerodynamic design and stability analysis response surface methodology for natural laminar flow wings from an aircraft system design point of view},
booktitle = {21st AIAA Applied Aerodynamics Conference; Orlando, FL; June 23-26.},
Conference: 21st AIAA Applied Aerodynamics Conference; Orlando, FL; June 23-26, 2003.
Lee, J.-M.S., P, D. & Mavris, D.N. Development of subsonic transports with natural laminar flow wings
1998 AIAA, Aerospace Sciences Meeting & Exhibit, 36th, Reno, NV; UNITED STATES; 12-15 Jan. 1998 conference
Abstract: The two main sources of drag that can account for more than 80 percent of the total drag for current subsonic aircraft are friction and induced drag. A new Natural Laminar Flow (NLF) wing design methodology has been established to minimize these two important sources of drag. According to this method, a synthesis and sizing code, is used to estimate the benefits of NLF technology at the system level, and determine optimal wing planform geometry and wing area for a given mission requirement. Then, the chordwise pressure distribution and the spanwise lift distribution of the previously optimized NLF wing planform from the sizing code are parameterized carefully on the basis of physical insights. An inverse aerodynamic design technique is then used to find the corresponding airfoil geometry for a given pressure distribution. Finally, a metamodel building method, the 'Response Surface Methodology' is used to minimize the drag of the wing at the design cruise condition, given by the sizing code, with respect to the parameters related to the chordwise pressure distribution and the spanwise lift distribution of the NLF wing simultaneously. In this procedure, the accurate prediction of the onset of laminar-to-turbulent transition is crucial to estimate the skin friction drag. (Author)
author = {Lee, Jae-Moon Schrage, and Daniel P and Mavris, Dimitri N},
title = {Development of subsonic transports with natural laminar flow wings},
booktitle = {AIAA, Aerospace Sciences Meeting & Exhibit, 36th, Reno, NV; UNITED STATES; 12-15 Jan. 1998},
Conference: AIAA, Aerospace Sciences Meeting & Exhibit, 36th, Reno, NV; UNITED STATES; 12-15 Jan. 1998.
Levine, S.W., Mark & Mavris, D. Comparison of turbofan & Q-fan propulsion systems for a small general aviation aircraft
Abstract: A comparison is made between turbofan propulsion systems and Q-fan propulsion systems for a small general aviation aircraft. The Q-fan (for 'quiet fan') is a multibladed shrouded fan engine concept developed by Hamilton Standard.
@conference{Levine2003,
author = {Levine, Simon Waters, and Mark and Mavris, Dimitri},
title = {Comparison of turbofan & Q-fan propulsion systems for a small general aviation aircraft},
Lewe, J.-H.A., DeLaurentis, B.-H., A, D. & Mavris, Dimitri N; Schrage, D.P. An integrated decision-making method to identify design requirements through agent-based simulation for personal air vehicle system
Abstract: A product's design requirements guide the next development efforts. Thus, correct decision-making is critical in generating design requirements as vehicle concepts are being formulated. A new method is proposed to account for system-of-systems aspects and to aid a decision-making process in synthesizing design requirements for a personal air vehicle system. The use of an agent-based modeling technique facilitates the abstraction of the key elements in the whole system. A traveling party is treated as an agent, and the infrastructure environment in the national transportation system is easily represented in the model. A number of simulations are performed to demonstrate the capability of this new approach. The method not only measures the effect of design requirements of a personal air vehicle system through sensitivity analyses, but also evaluates the effect of system technologies quantitatively, while maintaining the system-of-systems perspective. With this powerful method, designers can extract essential technical requirements that allow polishing of concept vehicles; policy makers can investigate the infrastructure and technology impact of new systems; and business planners can perform an analysis based on their own market assumptions. (Author)
@inproceedings{Lewe2002,
author = {Lewe, Jung-Ho Ahn, and Byung-Ho DeLaurentis, and Daniel A and Mavris, Dimitri N; Schrage, Daniel P},
title = {An integrated decision-making method to identify design requirements through agent-based simulation for personal air vehicle system},
Lewe, Jung-ho Upton, E., Mavris, D. & Schrage, D. An agent-based framework for evaluating future transportation architectures
Abstract: Modeling and evaluating behavior of the National Transportation System (NTS) is a strikingly difficult task. Nevertheless, there is a significant need for a way to model the NTS in order to study future transportation architectures that involve the cascade of interrelated effects of technology, infrastructure, and socioeconomic changes throughout the entire system. The approach proposed in this paper focuses on the individual users of the system, the travelers who make up the core users of the NTS, rather than on the system itself to circumvent the modeling difficulties arising from traditional approaches. A traveling party is treated as a unit agent, and the infrastructure environment in the whole system is conceptually represented in the agent-based model. Each agent is capable of making its own decisions with respect to changes in the simulation environment to meet its preprogrammed needs. The adaptive agent in a virtual NTS selects its best travel mode through a choice mechanism, currently implemented with a multinomial logit model. Hypothetical simulation scenarios, based on future vehicle technologies, system-level changes, economic disruptions, and societal perturbations, are compared against the baseline scenario to showcase the effects of these changes. Using this framework, decision-makers at various levels can investigate problems with an enhanced perspective.
@conference{Lewe2003,
author = {Lewe, Jung-ho Upton, E.G. and and Mavris, D.N. and Schrage, D.P.},
title = {An agent-based framework for evaluating future transportation architectures},
Li, Y.D., Daniel & Mavris, D. Advanced Rotorcraft Concept Development and Selection Using A Probabilistic Methodology
Abstract: The objective of the research described in this paper is to develop advanced personal air vehicle concepts based on rotorcraft configurations and among these identify the concept that has the highest probability of viability as measured by given criteria. These criteria include direct operating cost, noise, and travel speed, which are all critical to successful personal aircraft concepts. In developing the advanced concepts, statistical and probabilistic methods, including a response surface method approach and Monte Carlo simulation, are applied to construct a unified tradeoff environment that allows tradeoff of mission requirements, vehicle attributes, and technologies simultaneously. Three rotorcraft configurations are identified as the baseline vehicles in the environment: a helicopter, a gyroplane, and a tiltrotor. Subsequently, the application of particular advanced technologies is simulated and the impact upon the mission requirements is investigated. After the advanced technology versions of these baselines were developed, a joint probabilistic decision making technique was employed to select the advanced concept with the highest viability under a defined uncertainty model.
@conference{Li2003,
author = {Li, Yongchang DeLaurentis, and Daniel and Mavris, Dimitri},
title = {Advanced Rotorcraft Concept Development and Selection Using A Probabilistic Methodology},
Li, Y.M., Dimitri & DeLaurentis, D. The Investigation of a Decision-Making Technique Using the Loss Function
Abstract: In aircraft design, the decisions made during the conceptual or preliminary design phases play a large role in determining the success of the design. Supporting decision makers in these early design phases require a decision making technique with the capability of managing multiple conflicting criteria and capturing the associated uncertainties. The Joint Probability Decision making technique, which incorporates a multi-criteria and a probabilistic approach to systems design, is such a technique. This technique uses Probability of Success as the objective function, which is obtained by integrating the Joint Probability Density Function of the criteria over the area of criterion values that are of interest to the customer. However, the calculation of probability of success does not take the deviation of the solutions from the target values into account, which may be often important for concept selection. Also, this technique employs weighting coefficients to indicate the importance of each criterion when calculating the probability of success. However, representing the decision maker's preference by using the numerical weights is considered ineffective and usually involves a largely undefined trial-and-error weight-tweaking process. The study presented in this paper was done with the intention of enhancing the joint probability decision making technique so as to make it useful for concept selection through the utilization of Loss Function. The impact of the loss function in the decision making process is investigated in this paper, and an advanced rotorcraft concept selection problem employing the joint probability decision making technique with and without the loss function is performed in order to demonstrate the improved technique.
author = {Li, Yongchang Mavris, and Dimitri and DeLaurentis, Daniel},
title = {The Investigation of a Decision-Making Technique Using the Loss Function},
Lim, C.G.L., DeLaurentis, J.-H., A, D. & Mavris, D.N. A Methodology for Assessing Business Models of Future Air Transportation in the Atlanta Regional Transportation System
Abstract: A methodology employing physics-based and economics-based tools in conjunction with probabilistic treatment is developed to study Personal Air Vehicle business model. In the context of the paper, a business model is a mathematical representation of a service provider business operation. Vehicle concepts and hypothesized metrics such as mobility freedom and 'value of time' are embedded in the methodology. Market behavior of the complex transportation environment is captured as part of the equation through Agent-based Modeling and Monte Carlo Simulation techniques. This simulation platform for the transportation environment facilitates the case study of the Atlanta Regional Transportation System. The establishment of this model lays the foundation for creating a robust and adaptive design methodology that allows experts in fields other than aerospace engineering to contribute their expertise towards the realization of this very diverse and dynamic future air transportation system.
@conference{Lim2004,
author = {Lim, Choon Giap Lewe, and Jung-Ho DeLaurentis, and Daniel A and Mavris, Dimitri N},
title = {A Methodology for Assessing Business Models of Future Air Transportation in the Atlanta Regional Transportation System},
Classification: 03 Air Transportation and Safety (AH).
Liu, Z. & Mavris, D. A methodology for probabilistic creep-fatigue life assessment of hot gas path components
2004 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference; Palm Springs, CA; Apr. 19-22. conference
Abstract: Creep and fatigue are two major failure mechanisms for certain hot path gas turbine components. The creep-fatigue life consumption of a component is highly sensitive to variations in real operating conditions, material properties and geometry. The traditional method used for remaining life assessment assumes a set of fixed parameters at all times, and it fails to capture the variations. This translates into a significant loss of accuracy and unnecessary high maintenance and replacement cost. A new method was developed to capture these variations and improve the accuracy of remaining life assessment. First, all physics based analyses from variables (operating conditions, material properties, geometry, etc.) to creep and fatigue responses at critical regions of a component are automated. Then a set of metamodel is developed using Response Surface Method/ Design of Experiments method. In our previous researches funded by General Electric Power System, the metamodel approximated the physics based analyses from the variables to responses very accurately for two of their turbine blades. After verification for its accuracy, the metamodel can be used to efficiently compute creep and fatigue lives in operation. Future operating profile is forecasted based on monitored operating profile in both a conservative approach and a most-likely approach. The metamodel, along with a probabilistic method and a damage accumulation model are used to compute current damage accumulation and remaining life based on the operating profiles. The method leads to a computationally efficient remaining life assessment developed from complex realistic physics with relatively high accuracy. After proper verification the method should bring significant savings.
@conference{Liu2004,
author = {Liu, Zhimin and Mavris, Dimitri},
title = {A methodology for probabilistic creep-fatigue life assessment of hot gas path components},
booktitle = {45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference; Palm Springs, CA; Apr. 19-22.},
Conference: 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference; Palm Springs, CA; Apr. 19-22, 2004.
Classification: 38 Quality Assurance and Reliability (AH).
Liu, Z., Volovoi, V. & Mavris, D.N. Probabilistic remaining creep life assessment for gas turbine components under varying operating conditions
Abstract: A procedure proposed in this paper is intended to facilitate better assessment of creep and fatigue life for gas turbine components under varying high temperatures and stresses. The remaining life of a component depends highly on its operating conditions, which can vary significantly with time and from engine to engine due to usage and ambient conditions. This creates two major problems when trying to capture these variations in a life assessment analysis: (1) an analysis of life with constant operating conditions is very time consuming and costly, (2) the variations themselves are difficult to predict. These problems limit the ability to do life assessments using deterministic methods, and, as a result, the prediction of usable life of a component tends to be much lower than it should be. In this paper, Design of Experiments is used in conjunction with the Response Surface Method in order to approximate the analysis. The combination of these methods provides a fast and relatively accurate way to create a physics-based model. This facilitates dealing with the first problem. The extrapolation of future operating conditions and damage accumulation addresses the second problem, because the probabilistic method makes possible an online, real-time life assessment based on the historical operating profile of the component. Thus, the final product can be more accurate than results from a traditional deterministic approach. In addition to studying varying operating conditions, variations in geometry and material properties are investigated as well. These variations are more significant in design or disposition, but they still can be important in assessing the service life. Specifically, creep is chosen to illustrate the methodology, because it is one of the major failure mechanisms for gas turbine components under high temperature and stress. It is expected that the method can be extended to assess fatigue-creep life. (Author)
@inproceedings{Liu2002,
author = {Liu, Zhimin and Volovoi, Vitali and Mavris, Dimitri N},
title = {Probabilistic remaining creep life assessment for gas turbine components under varying operating conditions},
Classification: 39 STRUCTURAL MECHANICS (AH).
Lu, Z., Yang, E.-S.D., Daniel & Mavris, D. Formulation and test of an object-oriented approach to aircraft sizing
Abstract: Although aircraft sizing is a critical element in the conceptual and preliminary design phases, state-of-practice aircraft sizing computer programs seldom provide the flexibility needed to size revolutionary concept vehicles and to perform variable fidelity disciplinary analysis. Revolutionary concepts are future air vehicles that look, behave, and operate fundamentally differently than those in current and past experience. In order to address this problem and extend the state-of-the-art, this paper presents a new, object-oriented aircraft sizing framework. The framework builds upon recent developments mainly in the areas of multidisciplinary analysis and object-oriented programming. Domain and analysis scalabilities are achieved in this framework by modeling the building blocks of an aircraft sizing environment (e.g., mission profile and contributing disciplinary analysis tools) as objects. Further, sizing algorithms for particular revolutionary concepts being developed can be easily integrated with the proposed approach. Example applications utilizing this new sizing framework are provided in this paper for validation and test purposes.
@conference{Lu2004,
author = {Lu, Zhijie and Yang, Eun-Suk DeLaurentis, and Daniel and Mavris, Dimitri},
title = {Formulation and test of an object-oriented approach to aircraft sizing},
de Luis, J. & Mavris, D. Prediction methodology of an optimum turbofan engine cycle
Abstract: This paper summarizes the steps of sizing a turbofan engine for a specified flight condition. This is done by minimizing the specific fuel consumption, which is achieved by finding optimum pressure ratios for the fan and the low pressure turbine. Turbine inlet temperature is assumed to be given, while the bypass ratio is a fall-out from the analysis. The user has the option to either input the high pressure compressor pressure ratio or to determine an optimum value that maximizes the thermal efficiency of the engine. Following a series of steps described herein, this optimum cycle can be found for any flight altitude and Mach number combination, depending on the characteristics of the cycle and the component efficiencies. This analysis is limited to turbofan engines with separate nozzles for the fan exhaust flow and the core exhaust flow. In addition, both nozzle flows are fully expanded to atmospheric pressure. Using a memorandum written by R. O. Bullock in 1973 while working at the Airesearch Manufacturing Company, this process was expanded by creating a specific tool capable of calculating various performance parameters of interest and creating a series of curves, where the specific fuel consumption is minimized for each specified flight condition. This analysis method enables the analyst to determine the bypass ratio, as well as the pressure ratios, without having to re-run the analysis for each different case. Furthermore, these curves yield the trends that will minimize the specific fuel consumption, as well as determine the fan and low pressure turbine pressure ratios necessary to achieve this minimum.
@conference{Luis2004,
author = {de Luis, Jorge and Mavris, Dimitri},
title = {Prediction methodology of an optimum turbofan engine cycle},
Marx, W.J., Mavris, D.N. & Schrage, D.P. Cost/time analysis for theoretical aircraft production
Vol. 35(4)Technical Papers. Pt. 1, Journal of Aircraft (0021-8669). July-Aug, pp. 562-582,637-646 conference
Abstract: With the growing emphasis on affordability in aerospace systems design for future aircraft, there is a need for new techniques to predict accurate system and life cycle costs (LCCs). The prediction methods must be capable of quantifying cost differences resulting from material and manufacturing process alternatives. Existing cost models are primarily weight-based. A high-fidelity production cost model that accepts data from multiple levels of product design analysis was developed and is presented. The use of cost/time analysis (CTA) for aircraft production is demonstrated for the evaluation of production alternatives. The production-cost model and CTA techniques are included in an LCC simulation. Numerical results are presented for a CTA evaluation of advanced wing structural concepts for a supersonic transport. (Author)
@conference{Marx1998,
author = {Marx, William J and Mavris, Dimitri N and Schrage, Daniel P},
title = {Cost/time analysis for theoretical aircraft production},
booktitle = {Technical Papers. Pt. 1, Journal of Aircraft (0021-8669). July-Aug},
pages = {562-582,637-646},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 37th, Salt Lake City, UT; UNITED STATES; 15-17 Apr. 1996.
Marx, W.J., Mavris, D.N. & Schrage, D.P. Effects of alternative wing structural concepts on high speed civil transport life cycle costs
1996 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 1; UNITED STATES; 15-17 Apr. 1996, pp. 562-582 conference
Abstract: Integrated cost and engineering models were developed and used within a focused design perspective. A framework for the integrated product and process design of an aircraft system with a combined performance and economic perspective is described; this framework is based on the concept of a 'design for economics' approach. A production cost model is deyeloped that is sensitive to material and product/process selections for the wing structure. The use of cost/time analyses is described and applied for evaluation of process trades at the subcomponent level of design. Results of an Integrated Product/Process Development case study are presented for potential High Speed Civil Transport wing structural concepts. Cost-vs-performance studies indicate that an aircraft with a hybrid wing structural concept, though more expensive to manufacture than some homogeneous concepts, can have lower direct operating costs due to a lower take-off gross weight and less mission fuel required. (Author)
title = {Effects of alternative wing structural concepts on high speed civil transport life cycle costs},
booktitle = {AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 1; UNITED STATES; 15-17 Apr. 1996},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 1; UNITED STATES; 15-17 Apr. 1996.
Marx, W.J., Mavris, D.N. & Schrage, D.P. A hierarchical aircraft life cycle cost analysis model
1995 AIAA, Aircraft Engineering, Technology, and Operations Congress, 1st, Los Angeles, CA; UNITED STATES; 19-21 Sept. 1995 conference
Abstract: This paper presents an exploratory study for identification and quantification of the economic benefits or implications associated with wing cost variations. A hierarchical cost model structure is used to determine life cycle effects of design and manufacturing alternatives for the major structural components of the wing of a high speed civil transport aircraft concept. Preliminary results are presented relating the effects of up to a 25 percent variation in wing cost to overall manufacturing and operational returns on investment. It was discovered that a 25 percent reduction in wing costs, relative to a baseline wing, results in approximately a 3 percent increase in return on investment for the manufacturer. In addition, deviations in wing cost of 10 percent and 25 percent yielded acquisition price differences of 2.25 percent and 6.0 percent, respectively. These relatively small percentage differences in acquisition costs produced no significant changes in operational costs of the aircraft. Small changes were evident in the costs of financing and depreciating the aircraft, but these minor differentials had a negligible effect on the airline return on investment. (Author)
title = {A hierarchical aircraft life cycle cost analysis model},
booktitle = {AIAA, Aircraft Engineering, Technology, and Operations Congress, 1st, Los Angeles, CA; UNITED STATES; 19-21 Sept. 1995},
Conference: AIAA, Aircraft Engineering, Technology, and Operations Congress, 1st, Los Angeles, CA; UNITED STATES; 19-21 Sept. 1995.
Other Numbers: Contract: NGT-51101.
Classification: 11 Aircraft (MT); 83 ECONOMICS AND COST ANALYSIS (AH).
Marx, W.J., Mavris, D.N. & Schrage, D.P. Integrating design and manufacturing for a high speed civil transport wing
Vol. 3ICAS, Congress, 19th, Anaheim, CA, Proceedings; UNITED STATES; 18-23 Sept. 1994, pp. 3019-3028 conference
Abstract: The authors propose a methodology for an aircraft producibility assessment, including a knowledge-based system (KBS), that addresses both procedural and heuristic aspects of integrating design and manufacturing of a High Speed Civil Transport (HSCT) wing. The paper gives a brief background of selected previous supersonic transport studies followed by descriptions of key relevant design and manufacturing methodologies. Georgia Tech's Concurrent Engineering/Integrated Product and Process Development methodology is discussed with reference to this proposed conceptual producibility assessment. Evaluation criteria are presented that relate pertinent product and process parameters to overall product producibility. In addition, the authors' integration methodology and reasons for selecting a KBS to integrate design and manufacturing are presented in this paper. Finally, a proposed KBS is given, as well as statements of future work and overall investigation objectives. (Author)
title = {Integrating design and manufacturing for a high speed civil transport wing},
publisher = {Washington, DC: American Institute of Aeronautics and Astronautics, Inc.},
Marx, W.J., Mavris, D.N. & Schrage, D.P. Integrated product development for the wing structural design of the High Speed Civil Transport
1994 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 5th, Panama City Beach, FL, Technical Papers. Pt. 1; UNITED STATES; 7-9 Sept. 1994, pp. 12-21 conference
Abstract: An account is given of a research effort encompassing the development and integration of a manufacturing knowledge base and a rule-based reasoning system, with specific application to the NASA-coordinated HSCT research program. Integrated product development techniques are used to evaluate economical producibility and conduct optimization tradeoff studies. This approach involves encoding the knowledge of human experts concerning aircraft manufacturing and design into a tractable presentation. (AIAA)
@conference{Marx1994a,
title = {Integrated product development for the wing structural design of the High Speed Civil Transport},
Massey, K.H., DiFrancesco, M., Ben & Ender, Tommer Mavris, D. A System-of-Systems Design of a Guided Projectile Mortar Defense System
2006 24th AIAA Applied Aerodynamics Conference; San Francisco, CA; USA; 5-8 June 2006 conference
Abstract: A System-of-Systems design methodology is used to evaluate tradeoffs in the design of a guided bullet system for mortar defense. Guided bullets were designed to match the calibers of four different existing auto guns and were modeled in a six degree of freedom simulation. A bullet guidance system was developed based on proportional navigation and several control actuation schemes were modeled. The system simulation was setup to perform Monte Carlo analyses with noise models for various subsystems such as the gun controller and radar. Ranges of gun accuracies and ranges of radar noise were used to create a design space which also included the variation in gun caliber. A design of experiments approach was used to determine the simulation cases that needed to be run to map out the design space. Based on more than half a million independent simulations, a metamodel of the design space was created to capture the interactions between the gun, the projectiles, and the radar. This metamodel allows the user to rapidly evaluate the impact of design tradeoffs and to determine the best system based on his chosen metrics. Available metrics include, cost, weight, defended area, and combinations of the three. Initial results indicate that feasible designs for a guided bullet system are possible within the design space.
@conference{Massey2006,
author = {Massey, Kevin Heiges, and Michael DiFrancesco, and Ben and Ender, Tommer Mavris, Dimitri},
title = {A System-of-Systems Design of a Guided Projectile Mortar Defense System},
booktitle = {24th AIAA Applied Aerodynamics Conference; San Francisco, CA; USA; 5-8 June 2006},
Conference: 24th AIAA Applied Aerodynamics Conference; San Francisco, CA; USA; 5-8 June 2006.
Mavris, D. & Birney, M. Formulation of a stochastic, physics-based strategic business decision making environment
Abstract: Engine development projects present very difficult and complex problems for aircraft engine producers. A dependence upon the aircraft manufacturer for requirements that often change over the course of the aircraft's design creates a great deal of engineering uncertainty. Development program and competitive market uncertainties further complicate the decision-making task. With so much money at stake, the management for aircraft engine makers needs tools to better understand the problems that they face. A methodology to meet this need may be created using various tools from the engineering and management worlds. Probabilistic methods can create a stochastic representation of customer requirements in a physics-based simulation environment to deal with engineering uncertainty. Tools such as real options and game theory can assess the business uncertainty and competitive nature of the problem. By combining these together an environment can be created that links the engineering and business sides of program development as well as providing decision-makers with a clearer understanding of payoffs and risk. (Author)
@inproceedings{Mavris2002,
author = {Mavris, Dimitri and Birney, Mark},
title = {Formulation of a stochastic, physics-based strategic business decision making environment},
Mavris, D. & DeLaurentis, D. A Comprehensive, Robust Design Simulation Approach to the Evaluation/Selection of Affordable Technologies and Systems
1999 techreport
Abstract: This annual report documents the results of basic research in the area of affordability measurement and prediction science. A key result has been the formulation of a comprehensive, rational approach to technology identification, evaluation, and selection, to aid Navy decision-makers in developing new and more affordable systems.
@techreport{Mavris1999h,
author = {Mavris, Dimitri and DeLaurentis, Daniel},
title = {A Comprehensive, Robust Design Simulation Approach to the Evaluation/Selection of Affordable Technologies and Systems},
publisher = {NASA Center for AeroSpace Information, 7121 Standard Dr , Hanover, Maryland, 21076-1320, USA},
Report Number: NASA no. 19990116648; AD-A368433.
Publication Type: REPORT.
Classification: 10 Aerospace Engineering (General) (MT); 81 Administration and Management (AH).
Accession Number: 200610-10-090134 (MT); N00-10763 (AH).
Mavris, D. & Fernandez, I. Integration of Real Options Analysis into an Engine Development Decision Support System
Abstract: The decision of developing a new aircraft engine has never been an easy one. Engineering and manufacturing aircraft engines have always been very challenging tasks for the aerospace industry. These challenges are delimited not only by the technological and physical constraints that engineers face every day, but also by market, economic, political and many other uncertain factors that are not so easily quantifiable ahead of time. This paper identifies the main non-technical concerns that arise in the development of a new aircraft engine, and links them to the technical design specifications and the uncertainty that surround these, to make a valuable decision support system useful at the managerial level. The solution is presented at the end of the paper in the form of a methodology that, once perfected, will allow managers to better evaluate the feasibility of new projects, considering technical and managerial concerns, as well as their uncertainties, thereby minimizing risk.
@conference{Mavris2003,
author = {Mavris, Dimitri and Fernandez, Ismael},
title = {Integration of Real Options Analysis into an Engine Development Decision Support System},
Mavris, D.N. Exploration of Advanced Probabilistic and Stochastic Design Methods
Abstract: The primary objective of the three year research effort was to explore advanced, non-deterministic aerospace system design methods that may have relevance to designers and analysts. The research pursued emerging areas in design methodology and leverage current fundamental research in the area of design decision-making, probabilistic modeling, and optimization. The specific focus of the three year investigation was oriented toward methods to identify and analyze emerging aircraft technologies in a consistent and complete manner, and to explore means to make optimal decisions based on this knowledge in a probabilistic environment. The research efforts were classified into two main areas. First, Task A of the grant has had the objective of conducting research into the relative merits of possible approaches that account for both multiple criteria and uncertainty in design decision-making. In particular, in the final year of research, the focus was on the comparison and contrasting between three methods researched. Specifically, these three are the Joint Probabilistic Decision-Making (JPDM) technique, Physical Programming, and Dempster-Shafer (D-S) theory. The next element of the research, as contained in Task B, was focused upon exploration of the Technology Identification, Evaluation, and Selection (TIES) methodology developed at ASDL, especially with regards to identification of research needs in the baseline method through implementation exercises. The end result of Task B was the documentation of the evolution of the method with time and a technology transfer to the sponsor regarding the method, such that an initial capability for execution could be obtained by the sponsor. Specifically, the results of year 3 efforts were the creation of a detailed tutorial for implementing the TIES method. Within the tutorial package, templates and detailed examples were created for learning and understanding the details of each step. For both research tasks, sample files and tutorials are attached in electronic form with the enclosed CD. (Author)
@conference{Mavris,
author = {Mavris, Dimitri N},
title = {Exploration of Advanced Probabilistic and Stochastic Design Methods},
Notes: RECON No. 20030032965..
Publication Type: Monograph.
Mavris, D.N. Applications of Non-Deterministic Methods on Vehicle Conceptual Design
2001 Nondetermonistic Approaches and Their Potential for Future Aerospace Systems; 01 Sept. 2001, pp. 143-171 conference
Abstract: Moving from deterministic design to robust/probabilistic design methods amounts to an admission that uncertainty exists and has a significant impact on system performance. A paradigm shift is underway that attempts to change the way complex systems are being designed. Emphasis has shifted from design for performance at any cost to design for affordability. There is a need for a multi-disciplinary approach to the problem based on more sophisticated higher fidelity tools. The Response Surface Methodology (RSM) is a multivariate regression technique developed to model the response of a complex system using a simplified equation. RSM is based on the design of experiments methodology which gives the maximum power for a given amount of experimental effort. Example applications are presented to model this technique.
title = {Applications of Non-Deterministic Methods on Vehicle Conceptual Design},
booktitle = {Nondetermonistic Approaches and Their Potential for Future Aerospace Systems; 01 Sept. 2001},
Conference: Nondetermonistic Approaches and Their Potential for Future Aerospace Systems; 01 Sept. 2001.
Other Numbers: RECON no.20010110419..
Notes: NASA/CP-2001-21105.
Mavris, D.N. Demonstration of a Probabilistic Technique for the Determination of Economic Viability of Very Large Transport Configurations
1998 NASA no0107922 techreport
Abstract: Over the past few years, modem aircraft design has experienced a paradigm shift from designing for performance to designing for affordability. This report contains a probabilistic approach that will allow traditional deterministic design methods to be extended to account for disciplinary, economic, and technological uncertainty. The probabilistic approach was facilitated by the Fast Probability Integration (FPI) technique; a technique which allows the designer to gather valuable information about the vehicle's behavior in the design space. This technique is efficient for assessing multi-attribute, multi-constraint problems in a more realistic fashion. For implementation purposes, this technique is applied to illustrate how both economic and technological uncertainty associated with a Very Large Transport aircraft concept may be assessed. The assessment is evaluated with the FPI technique to determine the cumulative probability distributions of the design space, as bound by economic objectives and performance constraints. These distributions were compared to established targets for a comparable large capacity aircraft, similar in size to the Boeing 747-400. The conventional baseline configuration design space was determined to be unfeasible and marginally viable, motivating the infusion of advanced technologies, including reductions in drag, specific fuel consumption, wing weight, and Research, Development, Testing, and Evaluation costs. The resulting system design space was qualitatively assessed with technology metric "k" factors. The infusion of technologies shifted the VLT design into regions of feasibility and greater viability. The study also demonstrated a method and relationship by which the impact of new technologies may be assessed in a more system focused approach.
@techreport{Mavris1998,
title = {Demonstration of a Probabilistic Technique for the Determination of Economic Viability of Very Large Transport Configurations},
booktitle = {NASA no0107922},
Report Number: NASA no. 19980107922; NASA/CR-1998-207762; NAS 1.26:207762.
Other Numbers: Contract: NAG-1-1662.
Notes: NASA no. 19980107922.
Classification: 11 Aircraft (MT).
Accession Number: 2001-11-014646 (MT); N98-19350 (AH).
Mavris, D.N. Dual-Mission Large Aircraft Feasibility Study and Aerodynamic Investigation (Annual Report, Dec. 1995 - Dec. 1996)
Abstract: A Dual-Mission Large Aircraft, or DMLA, represents the possibility of a single aircraft capable of fulfilling both a Global Reach Aircraft (GRA) and Very Large Transport (VLT) roles. The DMLA, by combining the GRA and VLT into a single new aircraft, could possibly lower the aircraft manufacturer's production costs through the resulting increase in production quantity. This translates into lower aircraft acquisition costs, a primary concern for both the Air Force and commercial airlines. This report outlines the first steps taken in this study, namely the assessment of technical and economic feasibility of the DMLA concept. In the course of this project, specialized GRA and VLT aircraft were sized for their respective missions, using baseline conventional (i.e., lacking advanced enabling technologies) aircraft models from previous work for the Air Force's Wright Laboratory and NASA-Langley. DMLA baseline aircraft were then also developed, by first sizing the aircraft for the more critical of the two missions and then analyzing the aircraft's performance over the other mission. The resulting aircraft performance values were then compared to assess technical feasibility. Finally, the life-cycle costs of each aircraft (GRA, VLT, and DMLA) were analyzed to quantify economic feasibility. These steps were applied to both a two-engine aircraft set, and a four-engine aircraft set. (Derived from text)
author = {Dimitri N. Mavris},
title = {Dual-Mission Large Aircraft Feasibility Study and Aerodynamic Investigation (Annual Report, Dec. 1995 - Dec. 1996)},
Other Numbers: Contract: NAG1-1662.
Notes: Available from CASI HC A09/MF A02.
Mavris, D.N. Capability and affordability assessment of an HSHMR design using a combined response surface methodology/Monte Carlo simulation [High Speed Highly Maneuverable Rotorcraft Configuration]
1995 Aircraft Symposium, 33rd, Hiroshima, Japan, Proceedings; JAPAN; 8-11 Nov. 1995, pp. 611-614 conference
Abstract: An investigation has been conducted to determine a set of optimal design parameters for a high speed, highly maneuverable rotorcraft (HSHMR). The conceptual design optimization of this HSHMR was focused mainly on two major criteria: capability and affordability. The optimal capability and affordability parameter values were determined using a combined design of experiments, response surface methodology approach which allowed the evaluation and optimization of an overall evaluation criterion (OEC). According to the proposed approach, a response surface equation is developed for this OEC as a function of both control and noise design variables. The control variables can be selected in such a fashion as to optimize the response and minimize the variability created by the noise variables. (Author)
title = {Capability and affordability assessment of an HSHMR design using a combined response surface methodology/Monte Carlo simulation [High Speed Highly Maneuverable Rotorcraft Configuration]},
booktitle = {Aircraft Symposium, 33rd, Hiroshima, Japan, Proceedings; JAPAN; 8-11 Nov. 1995},
publisher = {Tokyo: Japan Society for Aeronautical and Space Sciences},
Conference: Aircraft Symposium, 33rd, Hiroshima, Japan, Proceedings; JAPAN; 8-11 Nov. 1995.
Mavris, D.N. An analytical method for the prediction of unsteady rotor/airframe interactions in forward flight (Ph.D. Thesis)
Abstract: A prediction code has been developed at Georgia Tech for the prediction of unsteady aerodynamic rotor-airframe interactions in forward flight. This method is based on the extension and coupling of a lifting line/free-wake rotor analysis (Scully free-wake code) and a source/doublet panel fuselage analysis (VSAERO). Coupling is achieved by iterating on the disturbance velocities induced by the airframe at the rotor inflow plane, and on the effect of the rotor and wake on the airframe. Physical flow features such as the energy addition in the wake and the blade passage effect have been modeled and included in the analysis. Provisions have been made to allow the rotor wake to distort freely in the presence of the airframe. In addition, the code has been extended to account for rotor wake/lifting surface interactions. Preliminary results (both time averaged and unsteady) from this study are presented along with a discussion on possible ways to improve correlations with experimental results. Results from this new code, called GTRAIC (Georgia Tech Rotor Airframe Interaction Code), have been validated against data obtained in the Georgia Tech 2.13 x 2.74 meter wind tunnel for a two bladed teetering rotor mounted over a cylindrical body with a hemispherical nose. (Dissert. Abstr.)
title = {An analytical method for the prediction of unsteady rotor/airframe interactions in forward flight (Ph.D. Thesis)},
Notes: Available from Univ. Microfilms Order No. DA8916164.
Mavris, D.N., Baker, A.P. & Schrage, D.P. Simultaneous assessment of requirements and technologies in rotorcraft design
2000 AHS International, Annual Forum, 56th, Virginia Beach, VA; UNITED STATES; 2-4 May 2000, pp. 1241-1250 conference
Abstract: Recent emphasis in the design and acquisition of complex systems has focused on the requirements that drive the design process. Most fundamental to the rotorcraft designer is the effect that requirements have on the system design. In this paper, the authors present a design environment for the simultaneous assessment of technologies, requirements, and design space. The creation of this environment is described along with the tools for its implementation. Examples of the various design spaces are presented for a civil tiltrotor. The requirements space for the civil tiltrotor is further examined. Finally, the benefit of applying this environment to the Joint Transport Rotorcraft is discussed. (Author)
@conference{Mavris2000a,
author = {Mavris, Dimitri N and Baker, Andrew P and Schrage, Daniel P},
title = {Simultaneous assessment of requirements and technologies in rotorcraft design},
booktitle = {AHS International, Annual Forum, 56th, Virginia Beach, VA; UNITED STATES; 2-4 May 2000},
Conference: AHS International, Annual Forum, 56th, Virginia Beach, VA; UNITED STATES; 2-4 May 2000.
Other Numbers: Contract: NCC2-945; N00014-97-1-0783.
Mavris, D.N., Baker, A.P. & Schrage, D.P. Technology infusion and resource allocation for a civil tiltrotor
2000 Vertical Lift Aircraft Design Conference, San Francisco, CA, Proceedings; UNITED STATES; 19-21 Jan. 2000 conference
Abstract: The methodology presented in this paper is concerned with the ability to make informed decisions early in the design time line in order to provide a feasible, viable, and robust system to the customer. Increasingly, the issues of affordability, uncertainty in design, and technology assessment are shaping the modern design environment. Current methodologies and techniques are not able to properly handle these issues. The research presented here builds on the authors' previous work which described an appropriate probabilistic design environment that allows for design in the presence of uncertainty as well as the infusion and assessment of new technologies. This environment is an essential part of a design methodology referred to as the Technology Identification, Evaluation, and Selection (TIES) method. The objective of this research is to provide a comprehensive, structured, and robust methodology for decision making in the early phases of rotorcraft design. In this paper the authors describe in detail the steps that encompass the TIES methodology. Illustrative examples of techniques, methods, and tools used during the methodology are presented as applied to NASA's Short Haul Civil Tiltrotor. (Author)
@conference{Mavris2000b,
title = {Technology infusion and resource allocation for a civil tiltrotor},
booktitle = {Vertical Lift Aircraft Design Conference, San Francisco, CA, Proceedings; UNITED STATES; 19-21 Jan. 2000},
Conference: Vertical Lift Aircraft Design Conference, San Francisco, CA, Proceedings; UNITED STATES; 19-21 Jan. 2000.
Other Numbers: A00-26651 06-05; Contract: NCC2-945; N00014-97-1-0783.
Notes: Available from AHS International, 217 N. Washington St., Alexandria, VA; Proceedings (A00-26651 06-05).
Mavris, D.N., Baker, A.P. & Schrage, D.P. Implementation of a technology impact forecast technique on a civil tiltrotor
Vol. 2AHS International Annual Forum, 55th, Montreal, Canada, Proceedings; UNITED STATES; 25-27 May 1999, pp. 1570-1582 conference
Abstract: The methodology presented in this paper is concerned with the ability to make informed decisions early in the design time-line, in order to provide a feasible, viable and robust system to the customer. Increasingly, the issues of affordability, uncertainty in design and technology impact assessment are shaping the modern design environment. Current methodologies and techniques are not able to properly handle these issues. The probabilistic design environment that allows for design in the presence of uncertainty, as well as the infusion and assessment of new technologies, is essential in a design methodology referred to as the Technology Identification, Evaluation and Selection (TIES) method. The objective of this research is to provide a comprehensive, structured, and robust methodology for decision making in the early phases of rotorcraft design. We present a brief summary of the probabilistic design environment, and introduce the steps that encompass the TIES methodology. The majority of the paper is devoted to applying the Technology Impact Forecasting portion of this method to NASA's Short Haul Civil Tiltrotor. (Author)
title = {Implementation of a technology impact forecast technique on a civil tiltrotor},
booktitle = {AHS International Annual Forum, 55th, Montreal, Canada, Proceedings; UNITED STATES; 25-27 May 1999},
Conference: AHS International Annual Forum, 55th, Montreal, Canada, Proceedings. Vol. 2; UNITED STATES; 25-27 May 1999.
Classification: 63 Mathematics and Computation (CE); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Accession Number: 2001-63-020282 (CE); A99-34998 (AH).
Subfile: Civil Engineering (CE); Aerospace & High Technology (AH).}
Mavris, D.N., Baker, A.P. & Schrage, D.P. Development of a methodology for the determination of technical feasibility and viability of affordable rotorcraft systems
Vol. 2AHS International, Annual Forum, 54th, Washington, DC, Proceedings; UNITED STATES; 20-22 May 1998, pp. 1070-1081 conference
Abstract: This paper describes a probabilistic design approach which has been formulated from an affordability viewpoint for the assessment of rotorcraft systems. This method places emphasis on the ability to rapidly examine the design space, identify constraint violations and provides insight as to how the feasible design space could be enlarged through the infusion of new technologies. The paper also provides a rationale as to why a probabilistic design approach is needed to properly examine and facilitate these assessments. The steps required to assess and provide for a technically feasible and viable design space are also outlined. Furthermore, thoughts as to how this technique could be used to investigate and account for tool fidelity modeling, technology readiness impact and benefit/risk/cost tradeoffs are also presented. Descriptions of candidate statistical and probabilistic techniques are provided as needed. Finally, the steps needed for the implementation of this methodology are presented for the design of a notional Civil Tiltrotor Transport. (Author)
title = {Development of a methodology for the determination of technical feasibility and viability of affordable rotorcraft systems},
booktitle = {AHS International, Annual Forum, 54th, Washington, DC, Proceedings; UNITED STATES; 20-22 May 1998},
Conference: AHS International, Annual Forum, 54th, Washington, DC, Proceedings. Vol. 2; UNITED STATES; 20-22 May 1998.
Other Numbers: A98-34317 09-01; Contract: NCC2-945.
Classification: 63 Mathematics and Computation (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Mavris, D.N., Baker, A.P. & Schrage, D.P. IPPD through robust design simulation for an affordable short haul civil tiltrotor
Vol. 2AHS, Annual Forum, 53rd, Virginia Beach, Proceedings; UNITED STATES; Apr. 29-May 1 1997, pp. 1615-1625 conference
Abstract: Beyond the Bell/Boeing 609, the next step in civil tiltrotor evolution will most likely be a larger capacity vehicle (about 40 passenger class) similar to NASA's vision of a Short Haul Civil Tiltrotor (SHCT). This vehicle will be designed, built, and operated in an era being shaped by today's increased emphasis on affordability. This paper discusses the authors' views on the subject and outlines the steps taken to develop a new methodology which will allow a true assessment of the affordability of such a SHCT. Affordability is not defined by cost metrics alone. Instead, it is based on the concept of value and tradeoffs between cost and mission effectiveness, measured by maintainability, reliability, safety, etc. In addition, the motivation for this shift in design philosophy and the resulting need for knowledge to be brought forward in the proposed methodology is reviewed. Furthermore, this shift in knowledge calls for a paradigm shift in the design evolution process based on the realization that decisions made during the early design phases are not deterministic in nature and should therefore be handled probabilistically. The approach taken acknowledges this need and defines a suitable probabilistic design environment. The fundamental building blocks of this method are also outlined and discussed including key concepts, tools, techniques, and the approach taken to implement this process. (Author)
title = {IPPD through robust design simulation for an affordable short haul civil tiltrotor},
Classification: 54 Health and Safety (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Mavris, D.N. & Bandte, O. A probabilistic approach to multivariate constrained robust design simulation
Abstract: An alternative to probabilistic design is presented that is based on a Fast Probability Integration technique. The paper critically reviews the combined Response Surface Equation/Monte Carlo Simulation (RSE/MCS) methodology and compares it with the Advanced Mean Value (AMV) method, one of several fast probability integration techniques. Both methods are used to generate cumulative distribution functions, which are being compared in an example case study of a High Speed Civil Transport concept. Based on the outcome of this study, an assessment and comparison of the analysis effort and time necessary for both methods is performed. The AMV method shows significant time savings over the RSE/MCS method, and generally yields more accurate cumulative probability distribution functions. By using the AMV method for distribution generation, robust design solutions to multivariate constrained problems may be obtained. These robust solutions optimize the objective function for the level of risk a decisionmaker is willing to take. (Author)
@inproceedings{Mavris1997b,
author = {Mavris, Dimitri N and Bandte, Oliver},
title = {A probabilistic approach to multivariate constrained robust design simulation},
Mavris, D.N., Bandte, O. & Brewer, J.T. A method for the identification and assessment of critical technologies needed for an economically viable HSCT
1995 AIAA, Aircraft Engineering, Technology, and Operations Congress, 1st, Los Angeles, CA; UNITED STATES; 19-21 Sept. 1995 inproceedings
Abstract: Researchers from the Aerospace Systems Design Laboratory (ASDL) at the School of Aerospace Engineering at Georgia Tech have been developing over the past three years a comprehensive methodology for the integration of aircraft design and manufacturing. NASA's High Speed Civil Transport (HSCT) concept has been selected as a pilot project for this study because of its potential global transportation payoffs and impact on U.S. world competitiveness. The proposed methodology is based on a Concurrent Engineering /Integrated Product and Process Development approach, and, in this case, is specifically applied to the design of an HSCT. The procedure employs the use of a Design of Experiments approach to facilitate the development of Response Surface Equations which capture the essence of sophisticated computationally intense disciplinary analyses tools and replace them by simple second-order polynomial equations. Since this aircraft has to be economically competitive to current subsonic transports, emphasis has been given throughout this study on understanding and assessing its economic viability. The determination of this objective is based on the required average yield per Revenue Passenger Mile, a metric that captures the concerns of all interested parties. The latest developments of ASDL's new methodology for the design of such affordable and reliable aircraft are outlined in this paper. However, the main objective of this paper is to describe the overall approach from concept formulation to concept feasibility and the identification and assessment of all possible means of achieving economic viability. Finally, different means of improving the economic viability of a hypothetical HSCT are examined, and their relative impact is quantified. (Author)
@inproceedings{Mavris1995a,
author = {Mavris, Dimitri N and Bandte, Oliver and Brewer, Jason T},
title = {A method for the identification and assessment of critical technologies needed for an economically viable HSCT},
Mavris, D.N., Bandte, O. & DeLaurentis, D.A. Determination of system feasibility and viability employing a joint probabilistic formulation
Abstract: The present paper outlines a method for probabilistic multi-criteria decision making. Recognizing the limitations of traditional probabilistic methods in accounting for multiple decision criteria in conceptual or preliminary design, this new method combines probabilistic treatment of uncertain information with a multi-criteria decision making technique. The paper describes how the method addresses a need in Multi-Disciplinary Optimization and Analysis as well as the advanced technology selection process in conceptual and preliminary design. The mathematical foundations of a general joint probabilistic formulation are outlined. Two specific functions are introduced that compute the joint probability: the joint empirical distribution function and the joint probability model. The utility of both functions is demonstrated in a proof of concept study for two criteria, applying both functions to a challenging aircraft design problem, the High Speed Civil Transport. This example application addresses two pressing issues: the identification of a feasible design space for a given design concept and the evaluation of viability of a given aircraft design. Finally, the advantages and limitations of the empirical distribution function method as well as the joint probability model are summarized. (Author)
author = {Mavris, Dimitri N and Bandte, Oliver and DeLaurentis, Daniel A},
title = {Determination of system feasibility and viability employing a joint probabilistic formulation},
Other Numbers: Contract: NAG1-1793; N00014-97-0783.
Mavris, D.N., Bandte, O. & DeLaurentis, D.A. Robust design simulation - A probabilistic approach to multidisciplinary design
1999 Journal of Aircraft (0021-8669). Jan.-Feb
Vol. 36(1), pp. 298-307 article
Abstract: Most current paradigms in multidisciplinary design analysis and optimization fail to address the presence of uncertainty at numerous levels of the design hierarchy and over the design process time line. Consequently, the issue of robustness of the design is neglected. An approach for the determination of robust design solutions is outlined in this paper, where uncertainty is quantified and its effects mitigated. The robust solution is found through maximization of the probability of an overall figure of merit achieving or exceeding a specified target. The proposed methodology is referred to as robust design simulation (RDS). Arguments as to why a probabilistic approach to aircraft design is preferable over the traditional deterministic approaches are presented, along with a step-by-step description of how one could implement the RDS. An application involving the high-speed civil transport is conducted as a case study to demonstrate the proposed method and to introduce an evaluation criterion that guarantees the highest customer satisfaction. (Author)
@article{Mavris1999b,
title = {Robust design simulation - A probabilistic approach to multidisciplinary design},
journal = {Journal of Aircraft (0021-8669). Jan.-Feb},
Mavris, D.N., Bandte, O. & Schrage, D.P. Effect of Mission Requirements on the Economic Robustness of an HSCT Concept
1996 International Society of Parametric Analysts, Cannes, France, Jun. 1996 conference
Abstract: Design for robustness and its subset design for economic robustness and viability are two areas in current design methodology and optimization research attracting a lot of attention. as the increasing number of publications and industry position papers in this field indicate. In fact. these publications attempt to address the paradigm shift taking place in industry! where design for performance is being replaced by design for affordability. That is designing and optimizing a system for a high yield while reducing the variation from that optimum yield. The study presented here can be viewed as a proof of concept for a proposed approach to design for robustness. called Robust Design Simulation (RDS). The paper outlines an alternative approach to Taguchi's, assigning probability distributions to uncontrollable factors (noise variables) which result in a distribution for the design objective instead of a point solution. The study also illustrates that indeed one is able to manipulate the mean and variance of the design objective concurrently, hence. optimizing a new Overall Evaluation Criterion (OEC) that is comprised of both the mean and variance of the design objective. The High Speed Civil Transport (HSCT) was utilized as an illustrative case to demonstrate the implementation of RDS. The objective of this case study is to show and quantify the effects of mission and aircraft sizing parameters on the mean and variance of direct and total operating cost as well as the required average yield per revenue passenger mile ($/RPM). Finally. the optimal mission requirement settings which yield an OEC that concurrently minimizes the mean $ /RPM as well as its variance are identified for the HSCT configuration studied. (Author)
author = {Dimitri N. Mavris and Oliver Bandte and Daniel P. Schrage},
title = {Effect of Mission Requirements on the Economic Robustness of an HSCT Concept},
booktitle = {International Society of Parametric Analysts, Cannes, France, Jun. 1996},
Report Number: NIPS-97-09885.
Notes: Presented at International Society of Parametric Analysts, Cannes, France, Jun. 1996; Available from CASI HC A03/MF A01.
Mavris, D.N., Bandte, O. & Schrage, D.P. Application of probabilistic methods for the determination of an economically robust HSCT configuration
1996 AIAA, NASA, and ISSMO, Symposium on Multidisciplinary Analysis and Optimization, 6th, Bellevue, WA, Technical Papers. Pt. 2; UNITED STATES; 4-6 Sept. 1996, pp. 968-978 conference
Abstract: This paper outlines an approach for the determination of economically viable robust design solutions using the High Speed Civil Transport (HSCT) as a case study. The advantages of a probability based aircraft design over the traditional point design approach are discussed. A new methodology called Robust Design Simulation (RDS) which treats customer satisfaction as the ultimate design objective is presented. RDS is based on a probabilistic approach to aerospace systems design, which views the chosen objective as a distribution function introduced by so-called noise or uncertainty variables. Since the designer has no control over these variables, a variability distribution is defined for each one of them. The cumulative effect of all these distributions causes the overall variability of the objective function. For cases where the selected objective function depends heavily on these noise variables, it may be desirable to obtain a design solution that minimizes this dependence. The paper outlines a step-by-step approach on how to achieve such a solution for the HSCT case study and introduces an evaluation criterion which guarantees the highest customer satisfaction. (Author)
author = {Mavris, Dimitri N and Bandte, Oliver and Schrage, Daniel P},
title = {Application of probabilistic methods for the determination of an economically robust HSCT configuration},
Mavris, D.N., Biltgen, P.T., Ender, T.R. & Cole, B. Technology Assessment and Capability Tradeoff Using Architecture-Based Systems Engineering Methodologies
2005 International Conference on Innovation & Integration in Aerospace Sciences; Belfast; Ireland; 4-5 Aug. 2005 conference
Abstract: The design of complex systems in the presence of changing requirements, rapidly evolving technologies, and design uncertainty continues to be a challenge. Furthermore, the design of future platforms must take into account the interoperability of a variety of heterogeneous systems and their role in a larger "system-of-systems" or "networks-ofsystems." To date, methodologies to address this complex interaction and optimize the system at the macro-level have lacked a clear direction and structure and have largely been conducted in an ad-hoc fashion. Furthermore, traditional optimization has centered around individual vehicles with little regard for the impact on the overall system. A key enabler for reduced cost and cycle time is the ability to rapidly analyze technologies and perform trade studies using a capability-based approach. While many entities have expressed a desire to perform capability-based design, the need for a structured discipline exists. To explore the science behind architecture-based systems engineering, establish a formal discipline for its application, and facilitate a transformation from a platform-centric design approach to one that examines capabilities at the top level, an architecture-based systems engineering testbed environment is proposed. This prototype design tool will be used to develop methods to determine the macro-level impact of asset-level technology infusion and is designed to be an adaptive, flexible systems engineering optimization tool that performs analysis on a wide range of platforms at varying levels of fidelity. A testbed demonstration environment for a notional Long Range Strike (LRS) military asset has been created which uses a surrogate modeling approach to enable inverse design and capability discovery. By specifying desired capabilities at the warfighter level, design decisions for platforms, weapons, and propulsion systems can be examined. Technology infusion can be studied at the system-of-systems level, providing insight into previously unknown behavior. Using an inverse design approach, requirements can flow down to physical systems or technologies can flow up to top-level goals. In this manner, spiral development, technology refresh, and technology obsolescence can be quantified. Optimization schemes that handle discrete and continuous variables can be used to determine the optimum force mix that satisfies a top-level objective function. This paper will highlight current progress in architecture-based systems engineering at the Georgia Tech Aerospace Systems Design Laboratory (ASDL) including the development of a testbed capability-based modeling and simulation environment and examples of how the environment can be queried to enable technology assessments and capability trades.
author = {Mavris , Dimitri N and Biltgen, Patrick T and Ender, Tommer R and Cole, Bjorn},
title = {Technology Assessment and Capability Tradeoff Using Architecture-Based Systems Engineering Methodologies},
booktitle = {International Conference on Innovation & Integration in Aerospace Sciences; Belfast; Ireland; 4-5 Aug. 2005},
publisher = {Queen's University, Belfast, Ireland},
Conference: International Conference on Innovation & Integration in Aerospace Sciences; Belfast; Ireland; 4-5 Aug. 2005.
Report Number: CEIAT 2005-0048.
Classification: 11 Aircraft (MT); 05 Aircraft Design, Testing and Performance (AH); 52 Numerical Analysis, Simulation, and Modeling (CI).
Mavris, D.N., Biltgen, P.T. & Weston, N.R. Advanced Design of Complex Systems Using the Collaborative Visualization Environment (CoVE)
Abstract: This paper summarizes and introduces the Collaborative Visualization Environment (CoVE) at the Aerospace Systems Design Laboratory (ASDL) at Georgia Tech. The CoVE is an advanced visualization facility consisting of an 18 ft x 10 ft display wall for high-resolution real-time visualization in support of collaborative design activities. Incorporating the latest advances in computing technology and graphics processing, the CoVE allows for the simultaneous display of a large amount of information and manages this information in a way that facilitates increased awareness of the design. Tools and techniques developed at ASDL not only increase the speed and fidelity of the design process but also allow for increased transparency of this process. For the first time, a sensitivity matrix with over sixty independent and dependent variables can be visualized simultaneously. This is in contrast to a typical display system where only about 15 percent of the information associated with a problem can be simultaneously visualized.
author = {Mavris, Dimitri N and Biltgen, Patrick T and Weston, Neil R},
title = {Advanced Design of Complex Systems Using the Collaborative Visualization Environment (CoVE)},
Classification: 62 Computer Systems (AH).
Mavris, D.N. & DeLaurentis, D. Methodology for examining the simultaneous impact of requirements, vehicle characteristics, and technologies on military aircraft design
2000 International Congress of Aeronautical Sciences, 22nd, Harrogate, United Kingdom; INTERNATIONAL ORGANIZATION; 27 Aug.-1 Sept. 2000 conference
Abstract: The process of systems engineering has always emphasized the definition of requirements as the first step toward product development. Typically, however, these requirements were examined in isolation from the potential systems and technologies they would likely impact. Further, requirements were treated deterministically during design, which sometimes led to actual systems that were non-robust when different requirements were encountered. Thus, there is a need to examine requirements early on and in a new way. This "new way" must include an environment for the simultaneous examination of requirements, design variables, and technologies. Further, this environment must be built in a probabilistic fashion since the requirements may be ambiguous and/or uncertain, the eventual cost and performance of critical technologies are highly uncertain, and the possibility of system "growth" must be accounted. The ultimate goal of the probabilistic approach is finding solutions robust to these uncertainties. A methodology for the creation of just such an environment is described in this paper. The implementation of the methodology is demonstrated through an example study of a notional, multi-role fighter aircraft. Important visualization and probabilistic analysis techniques are highlighted. The approach is found to be extremely valuable, especially in light of the recent initiation of several major programs in the aerospace sector which exhibit the challenges of joint service requirements, the need for advanced technologies, and an increasing emphasis on affordability. (Author)
@conference{Mavris2000c,
author = {Mavris, Dimitri N and DeLaurentis, Daniel},
title = {Methodology for examining the simultaneous impact of requirements, vehicle characteristics, and technologies on military aircraft design},
booktitle = {International Congress of Aeronautical Sciences, 22nd, Harrogate, United Kingdom; INTERNATIONAL ORGANIZATION; 27 Aug.-1 Sept. 2000},
Conference: International Congress of Aeronautical Sciences, 22nd, Harrogate, United Kingdom; INTERNATIONAL ORGANIZATION; 27 Aug.-1 Sept. 2000.
Report Number: ICAS Paper 2000-1.4.4.
Other Numbers: Contract: N00014-97-1-0783.
Classification: 63 Mathematics and Computation (CE); 11 Aircraft (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Mavris, D.N. & DeLaurentis, D. An integrated approach to military aircraft selection and concept evaluation
Abstract: The design (or evaluation) of military aircraft, by nature, is a process consisting of conflicting goals and objectives at the conceptual, preliminary, and detailed levels. Affordability, mission capability, availability (operational readiness), wartime survivability, and peacetime safety are five of the main attributes required of modern weapon systems. Traditional approaches for system evaluation or optimization have focused on one, perhaps two, of these attributes in isolation. At Georgia Tech's Aerospace Systems Design Laboratory (ASDL), a methodology has been developed which takes account of the combined effect of each of the '-ilities' plus safety in providing a means to evaluate alternative designs. The centerpiece of this approach is the Overall Evaluation Criterion (OEC). The OEC is an equation consisting of five metrics, one for each of the attributes. These five terms are pre-multiplied by so-called attribute importance coefficients, which represent the ability to tailor the OEC to the evaluator's preferences. The purpose of this paper is to detail the form of this OEC, describe the appropriate metrics for each of the five attributes which make up the criterion, illustrate an algorithm for their concurrent calculation, and conclude by suggesting a novel way of quantifying an evaluation by accounting for the 'voice of the customer'. (Author)
title = {An integrated approach to military aircraft selection and concept evaluation},
Mavris, D.N. & DeLaurentis, D.A. A probabilistic approach for examining aircraft concept feasibility and viability
2000 Aircraft Design (1369-8869). June 2000
Vol. 3(2), pp. 79-101 article
Abstract: A novel approach to assessing aircraft system feasibility and viability is presented, with special emphasis on modeling and estimating the impact of new technologies. The approach is an integral part of an overall stochastic, life-cycle design process under development by the authors, which is to address the new measure for system value: affordability. Stochastic methods are proposed since the design process is immersed in ambiguity and uncertainty, both of which vary with time as knowledge increases about the system behavior. The specific task addressed in this paper of examining system feasibility and viability is encapsulated in the five steps of the Concept Feasibility Assessment approach. The rationale and technical foundations of each step are explained, and the approach is compared to more traditional, deterministic means for examining a design space and evaluating technology impacts. Finally, the techniques are implemented on a supersonic transport design problem to highlight the power of the approach on a problem of significant interest to the international aerospace community. Several innovative avenues for viewing the design and technology spaces are employed in assessing first feasibility and then viability for the problem. (Author)
@article{Mavris2000d,
author = {Mavris, Dimitri N and DeLaurentis, Daniel A},
title = {A probabilistic approach for examining aircraft concept feasibility and viability},
journal = {Aircraft Design (1369-8869). June 2000},
Conference: UNITED KINGDOM.
Mavris, D.N. & DeLaurentis, D.A. A stochastic design approach for aircraft affordability
1998 ICAS, Congress, 21st, Melbourne, Australia; INTERNATIONAL ORGANIZATION; 13-18 Sept. 1998 conference
Abstract: A novel approach to assessing aircraft system feasibility and viability over time is presented, with special emphasis on modeling and estimating the impact of new technologies. The approach is an integral part of an overall stochastic, life-cycle design process under development by the authors, which is to address the new measure for system value, affordability. Stochastic methods are proposed since the design process is immersed in ambiguity and uncertainty, both of which vary with time as knowledge increases about the system behavior. The specific task of examining system feasibility and viability is encapsulated and explained in five steps. The probabilistic approach contained in these steps is compared to more traditional, deterministic means for examining a design space and evaluating technology impacts. Finally, the techniques are implemented on an example problem to highlight the additional realism and information that is obtained. The example is based on a High Speed Civil Transport vehicle design and is meant to illustrate the power of the technique on a current problem of significant interest to the international aerospace community. (Author)
title = {A stochastic design approach for aircraft affordability},
booktitle = {ICAS, Congress, 21st, Melbourne, Australia; INTERNATIONAL ORGANIZATION; 13-18 Sept. 1998},
Conference: ICAS, Congress, 21st, Melbourne, Australia; INTERNATIONAL ORGANIZATION; 13-18 Sept. 1998.
Report Number: ICAS Paper 98-6,1,3.
Other Numbers: Contract: N00014-97-1-0783; NSF DMI-97-34234; NAG1-1793.
Mavris, D.N., DeLaurentis, D.A., Bandte, O. & Hale, M.A. A stochastic approach to multi-disciplinary aircraft analysis and design
Abstract: Within the context of multidisciplinary aircraft analysis and design, a new approach has been formulated and described which allows for the rapid technical feasibility and economic viability assessment of multiattribute, multiconstrained designs. The approach, Virtual Stochastic Life Cycle Design, facilitates the multidisciplinary consideration of a system, accounting for life-cycle issues in a stochastic fashion. The life-cycle consideration is deemed essential in order to evaluate the emerging, all encompassing system objective of affordability. The stochastic treatment is employed to account for the knowledge variation/uncertainty that occurs in time through the various phases of design. Variability found in the treatment of assumptions, ambiguous requirements, code fidelity (imprecision), economic uncertainty, and technological risk are all examples of categories of uncertainty that the proposed probabilistic approach can assess. For cases where the problem is overconstrained and a feasible solution is not possible, the proposed method facilitates the identification and provides guidance in the determination of potential barriers which will have to be overcome via the infusion of new technologies. (Author)
author = {Mavris, Dimitri N and DeLaurentis, Daniel A and Bandte, Oliver and Hale, Mark A},
title = {A stochastic approach to multi-disciplinary aircraft analysis and design},
Other Numbers: Contract: NAG1-1793; NAG2-1047.
Mavris, D.N., DeLaurentis, D.A., Hale, M.A. & Tai, J.C.M. Elements of an emerging virtual stochastic life cycle design environment
Abstract: The challenge of designing next-generation systems that meet goals for system effectiveness, environmental compatibility, and cost has grown to the point that traditional design methodologies are becoming ineffective. Increases in the analysis complexity required the number of objectives and constraints to be evaluated, and the multitude of uncertainties in today's design problems are primary drivers of this situation. A new environment for design has been formulated to treat this situation. It is viewed as a testbed, in which new techniques in such areas as design-oriented /physics-based analysis, uncertainty modeling, technology forecasting, system synthesis, and decision-making can be posed as hypotheses. Several recent advances in elements of this multidisciplinary environment, termed the Virtual Stochastic Life Cycle Design Environment, are summarized. (Author)
author = {Mavris, Dimitri N and DeLaurentis, Daniel A and Hale, Mark A and Tai, Jimmy C M},
title = {Elements of an emerging virtual stochastic life cycle design environment},
Mavris, D.N., DeLaurentis, D.A. & Soban, D.S. Probabilistic assessment of handling qualities characteristics in preliminary aircraft design
Abstract: A method is introduced and demonstrated which uses parametric stability derivative data (in the form of regression equations) and probabilistic analysis techniques to evaluate the impact of uncertainty on the handling qualities characteristic of a family of aircraft alternatives. While the method is based on the use of elementary design parameters familiar to the configuration designer, it enables the computation of responses more familiar to the stability and control engineer. This connection is intended to bring about a more complete accounting of stability and handling quality characteristics in aircraft design, based on engineering analysis instead of historical data. Another key advantage of the method is that it allows for the quantification of analysis imprecision and information quantity/quality tradeoffs through fidelity uncertainty models. The metrics for these quantifications are the cumulative distribution function and the probability sensitivity derivatives. The method is exemplified through the investigation of the longitudinal handling qualities trends for a defined High Speed Civil Transport design space, in the presence of fidelity uncertainty in the stability derivatives. (Author)
@conference{Mavris1998d,
author = {Mavris, Dimitri N and DeLaurentis, Daniel A and Soban, Danielle S},
title = {Probabilistic assessment of handling qualities characteristics in preliminary aircraft design},
Mavris, D.N. & Garcia, E. Framework for the assessment of capacity and throughput technologies
Abstract: The demand for air travel is expanding beyond the capacity of existing airports and ATC. This excess traffic often results in delays and compromised safety. Therefore, a number of initiatives to improve airport capacity and throughput have been proposed. However, in order to assess the impact of these technologies on commercial air traffic one must move beyond the vehicle to a system-of-systems point of view. This top-level point of view must include consideration of the aircraft, airports, air traffic management and airlines that make up the airspace system. In addition to the analyses of each of these components and their interactions, a thorough investigation of capacity and throughput technologies requires due consideration of other pressures such as economics, safety, and government regulations. Furthermore, the air traffic system is inherently variable with constant changes in everything from fuel prices to the weather. Thus, the development of a modeling environment that encompasses all these sources of uncertainty and the methodology to be used in a probabilistic evaluation of technological impacts are the subject of this paper. (Author)
@conference{Mavris2000e,
author = {Mavris, Dimitri N and Garcia, Elena},
title = {Framework for the assessment of capacity and throughput technologies},
Classification: 11 Aircraft (MT); 3 AIR TRANSPORTATION AND SAFETY (AH).
Mavris, D.N., German, B.J., Branscome, E.C., Frits, A.P. & Yiakas, N.C. An Evaluation of Green Propellants for an ICBM Post-Boost Propulsion System
2000 (20010029826) techreport
Abstract: Propellant toxicity is a major concern in storing, maintaining, and transporting strategic missiles. Many low toxicity 'green' propellants have been developed which hold the potential of increasing the safety and lowering the operation and support costs of liquid-fueled strategic missile propulsion systems. This study evaluates several green propellants for use in a notional next-generation post-boost propulsion system (PBPS). The mission and physical dimensions for this PBPS were defined by the requirements of the current Minuteman 3 propulsion system rocket engine (PSRE). Possible propellants were initially screened in terms of toxicity, performance, and technical feasibility for the PBPS application with a multi-attribute ranking method based on an overall evaluation criterion (OEC). Promising propellants were identified, and candidate PBPS concepts were developed and sized for each of these propellants. These concepts were evaluated in terms of weight, cost, and technical risk to determine which concepts, and hence propellants, show the most promise for the application. Probabilistic techniques were employed to explore the effects of uncertainty in the propellant performance and structural weight estimates. The results indicate that high-test peroxide (HTP) combined with either an ethanol-based nontoxic hypergolic miscible fuel (NHMF) or competitive impulse non-carcinogenic hypergol (CINCH) is a very viable propellant solution.
author = {Mavris, Dimitri N and German, Brian J and Branscome, E C and Frits, Andrew P, and Yiakas, Nicholas C,},
title = {An Evaluation of Green Propellants for an ICBM Post-Boost Propulsion System},
number = {20010029826},
Report Number: RECON no. 20010029826, AD-A386589.
Notes: Available from Aerospace Dispatch; Voice: 800 662 1545; Fax: 816 926 8794; E-Mail: dispatch@aiaa.org.
Classification: 28 PROPELLANTS AND FUELS (AH).
Mavris, D.N. & Hayden, W.T. Probabilistic assessment of the impact of new technologies on an HSCT
1998 ISSMO/NASA/AIAA First Internet Conference on Approximations and Fast Reanalysis in Engineering Optimization, Proceedings; UNITED STATES; 14-27 June 1998 conference
Abstract: This presentation discusses how response surface techniques and probabilistic analysis methods are integrated into aircraft design methodology in order to introduce physics-based analysis and uncertainty into the design process, assess the need for new technologies in an aerospace system, and analyze their impact on performance and economic metrics. The aircraft chosen for this study is the High Speed Civil Transport (HSCT), a supersonic commercial transport currently under development. This aircraft is envisioned to cruise at Mach 2.4, carry 300 passengers, and have a range of 5000 NM. (Author)
author = {Mavris, Dimitri N and Hayden, William T},
title = {Probabilistic assessment of the impact of new technologies on an HSCT},
booktitle = {ISSMO/NASA/AIAA First Internet Conference on Approximations and Fast Reanalysis in Engineering Optimization, Proceedings; UNITED STATES; 14-27 June 1998},
publisher = {Hampton, VA: NASA Langley Research Center},
Conference: ISSMO/NASA/AIAA First Internet Conference on Approximations and Fast Reanalysis in Engineering Optimization, Proceedings; UNITED STATES; 14-27 June 1998.
Classification: 12 Spacecraft (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Mavris, D.N. & Hayden, W.T. Probabilistic analysis of an HSCT modeled with an equivalent laminated plate wing
1997 AIAA and SAE, 1997 World Aviation Congress, Anaheim, CA; UNITED STATES; 13-16 Oct. 1997 conference
Abstract: The equivalent plate structural analysis code ELAPS is used to model the wing structure of the HSCT, and the Fast Probability Integration (FPI) technique is used to probabilistically assess the design space. After the ELAPS model is generated in a parametric manner, the structure is optimized to yield a weight for each component of the wing. A Response Surface Methodology approach is then implemented using Design of Experiments tables and an analysis of variance to generate response surface equations in terms of the most influential design variables for these wing component weights, as well as for the fuel volume available. These expressions are substituted into the sizing and synthesis code FLOPS in order to conduct system level design trade studies. The results of this study indicate that the HSCT has only a 20 percent probability of achieving the system level design constraint of a 1,000,000 lb take-off gross weight with the current level of technology and has no chance of achieving the desired goal of 750,000 lb. Through the use of new enabling technologies, however, these weight levels can be reduced to increase the probability of achieving technical feasibility and improve its economic viability. (Author)
title = {Probabilistic analysis of an HSCT modeled with an equivalent laminated plate wing},
Mavris, D.N. & Hayden, W.T. Formulation of an IPPD methodology for the design of a supersonic business jet
1996 SAE and AIAA, World Aviation Congress, 1st, Los Angeles, CA; UNITED STATES; 21-24 Oct. 1996 inproceedings
Abstract: The 1996 AIAA/United Technologies/Pratt & Whitney Individual Undergraduate Design Competition has issued a Request for Proposal for the conceptual design of a supersonic cruise business jet. The design of this aircraft considered both performance and economic issues in the conceptual design phase. Through the use of Response Surface Methodology and Design of Experiments techniques, the aerodynamics of this vehicle was modeled and incorporated into an aircraft sizing code, FLOPS. This program was then combined with an aircraft life-cycle cost routine, ALCCA, and response surfaces were created for the optimization of an Overall Evaluation Criterion (OEC) which considered both mission capability and affordability issues. The OEC for this study was determined through a Quality Function Deployment analysis considering both the voice of the customer and the voice of the engineer. Using a Robust Design Simulation (RDS) approach, an economic uncertainty analysis was performed to optimize the aircraft while minimizing the sensitivity of these parameters to fluctuations in variables over which the designer has no control. The result is an aircraft which can cruise at Mach 2.0 for 3160 nm, weighs 60314 lb, has a balanced field length of less than 7000 ft, and has a mean acquisition cost of $37.523 million in 1992 dollars. (Author)
title = {Formulation of an IPPD methodology for the design of a supersonic business jet},
Mavris, D.N. & Kirby, M.R. Technology Identification, Evaluation, and Selection (TIES) for commercial transport aircraft
1999 SAWE, Annual Conference, 58th, San Jose, CA; UNITED STATES; 24-26 May 1999 conference
Abstract: This paper outlines a comprehensive, structured, and robust methodology for decision making in the early phases of aircraft design. The proposed approach is referred to as the Technology Identification, Evaluation, and Selection (TIES) method. The nine-step process provides the decision maker/designer with an ability to easily assess and trade-off the impact of various technologies in the absence of sophisticated, time-consuming mathematical formulations for project resource allocation. The method also provides a framework where technically feasible and economically viable alternatives can be identified with accuracy and speed while the impact on the economics is quantified. Furthermore, structured and systematic techniques are utilized to identify possible concepts and evaluation criteria by which comparisons could be made. Through the implementation of each step, the best family of alternatives for a customer-focused overall measure of value can be identified and assessed subjectively or objectively. This method was applied to a 150 passenger, intra-continental commercial transport as a proof of concept investigation. (Author)
author = {Mavris, Dimitri N and Kirby, Michelle R},
title = {Technology Identification, Evaluation, and Selection (TIES) for commercial transport aircraft},
booktitle = {SAWE, Annual Conference, 58th, San Jose, CA; UNITED STATES; 24-26 May 1999},
Conference: SAWE, Annual Conference, 58th, San Jose, CA; UNITED STATES; 24-26 May 1999.
Report Number: SAWE Paper 2456.
Mavris, D.N. & Kirby, M.R. Takeoff/landing assessment of an HSCT with pneumatic lift augmentation
Abstract: Pneumatic technologies, such as Circulation Control airfoils, have been experimentally demonstrated to generate very high lift coefficients at low angles of attack. These blown airfoils offer great potential for advanced subsonic transports. Yet, the potential of this particular pneumatic technology is not limited to subsonic aircraft. In fact, Circulation Control has been chosen as an enabling technology to be applied on a generic High Speed Civil Transport (HSCT) under NASA Grant NAG-1-1517. Research on this contract was directed to a first-order quantitative estimate of the impact of Circulation Control on the takeoff and landing performance of an HSCT and is summarized in this paper. A reference point was established with an HSCT utilizing conventional high-lift devices that resulted in a takeoff field length of approximately 13,000 ft. The incremental changes in lift and drag established from the wind tunnel experiments performed in the above stated grant were then applied to this configuration and the low speed performance enhancements and degradations were quantified. The application of Circulation Control was shown to reduce the takeoff field length by as much as 31 percent from the reference point. This result strongly warrants further investigations with higher order analysis since the first order estimate shows significant improvements in low speed performance of an HSCT with Circulation Control pneumatic technology. (Author)
title = {Takeoff/landing assessment of an HSCT with pneumatic lift augmentation},
Mavris, D.N. & Kirby, M.R. Preliminary assessment of the economic viability of a family of Very Large Transport configurations
Abstract: A family of Very Large Transport (VLT) concepts was studied as an implementation of the affordability aspects of the Robust Design Simulation (RDS) methodology. The VLT is envisioned to be a high-capacity long-range subsonic transport. Various configurations with different levels of technology were compared, based on affordability issues, to a Boeing 747-400. The varying technology levels prompted a need for an integration of a sizing /synthesis (FLOPS) code with an economics package (ALCCA). The integration enables a direct evaluation of the added technology on a configuration's economic viability. The determination of the viability was based on the assessment of the following evaluation criteria: average yield per Revenue Passenger Mile, Total Operating Cost per day, acquisition cost, airframe manufacturer's cash flow, and airline's return on investment. The final conclusion of this analysis is that the 800-passenger configuration would meet most of the market demand of the 250 city pairs considered. This paper reviews the RDS methodology and how it was applied to determine the economic viability of a VLT concept. In addition, it documents the results of the method used to determine the economic viability of a family of VLT configurations and the most affordable VLT configuration for a specified market demand. (Author)
title = {Preliminary assessment of the economic viability of a family of Very Large Transport configurations},
Mavris, D.N., Liou, S., Komerath, N. & McMahon, H. Measurement and computation of the velocity field of a cylinder in the wake of a rotor in forward flight
1989 AIAA, Fluid Dynamics, Plasma Dynamics and Lasers Conference, 20th, Buffalo, NY; UNITED STATES; 12-14 June 1989, pp. 10 conference
Abstract: The problem of predicting the flowfield around a rotorcraft in low-speed forward flight is studied using a potential-flow code, whose results are compared with surface pressure measurements and flow velocity measurements. The test case used is a 2-bladed teetering rotor above a hemisphere- cylinder airframe in a wind tunnel. The dominant features of this problem are modeled by a lifting line/lifting surface rotor model with a free wake distorting in the presence of the airframe. The airframe flowfield is modeled using a source/doublet panel method. The instantaneous flowfield is computed at specified intervals of rotor azimuth, with the effects of blade motion added to the formulation. Modeling the energy addition at the rotor using actuator segments leads to successful prediction of the time- averaged pressure field. The periodic velocity variations along the spine of the airframe are predicted successfully. When a fully unsteady potential formulation is used, however, large differences appear between measured and computed periodic velocity at the sides of the airframe. These are attributed to the inadequate understanding of interaction of the rotor tip vortices with the airframe surface, as well as to inadequate modeling of the flowfield around the rotor hub. (Author)
author = {Dimitri N. Mavris and S.G. Liou and N.M. Komerath and H.M. McMahon},
title = {Measurement and computation of the velocity field of a cylinder in the wake of a rotor in forward flight},
booktitle = {AIAA, Fluid Dynamics, Plasma Dynamics and Lasers Conference, 20th, Buffalo, NY; UNITED STATES; 12-14 June 1989},
Report Number: AIAA Paper 1989-1844; AD-A217141.
Other Numbers: Contract: DAAG29-82-K-0084.
Classification: 11 Aircraft (MT); 2 AERODYNAMICS (AH).
Mavris, D.N., Mantis, G.C. & Kirby, M.R. Demonstration of a probabilistic technique for the determination of aircraft economic viability
Abstract: Over the past few years, modern aircraft design has experienced a paradigm shift from designing for performance to designing for affordability. This paper contains a probabilistic approach that will allow traditional deterministic design methods to be extended to account for disciplinary, economic, and technological uncertainty. The probabilistic approach was facilitated by Fast Probability Integration (FPI), a technique which allows the designer to gather valuable information about the vehicle's behavior in the design space. This technique is efficient for assessing multi-attribute, multi-constraint problems in a more realistic fashion. For implementation purposes, this technique is applied to illustrate how both economic and technological uncertainty associated with a Very Large Transport aircraft may be assessed. The assessment is evaluated with the FPI technique to determine the cumulative probability distributions of the design space, as bound by economic objectives and performance constraints. These distributions were compared to establish targets for a comparable large capacity aircraft, similar in size to the Boeing 747-400. The conventional baseline configuration design space was determined to be marginally feasible and nonviable, motivating the infusion of advanced technologies, including laminar flow control, advanced materials, and advances in propulsion technology as to reflect 2005 entry into service. (Author)
author = {Mavris, Dimitri N and Mantis, George C and Kirby, Michelle R},
title = {Demonstration of a probabilistic technique for the determination of aircraft economic viability},
Mavris, D.N. & Qiu, S. An improved process for the generation of drag polars for use in conceptual/preliminary design
Abstract: One of the most essential contributors in the aircraft sizing and synthesis process is the creation and utilization of accurate drag polars. An improved general procedure to generate drag polars for conceptual and preliminary design purposes in the form of Response Surface Equations (RSEs) is outlined and discussed. This approach facilitates and supports aerospace system design studies as well as Multi-disciplinary Analysis and Optimization. The analytically created RSEs replace the empirical aerodynamic relations or historical data found in sizing and synthesis codes, such as the Flight Optimization System (FLOPS). These equations are commonly incorporated into system level studies when a configuration falls beyond the conventional realm. The approach described here is a statistics-based methodology, which combines the use of the Design of Experiments and the Response Surface Method (RSM). Computational aerodynamic codes based on linearized potential flow and boundary layer theory are employed to generate the needed parametric relationships. The process is facilitated through the use of an automated computational architecture that is capable of handling massive exchanges of data and information. The aforementioned process is demonstrated through an implementation of the procedure for a High Speed Civil Transport concept. The accuracy of these RSEs is tested to demonstrate the fidelity and accuracy of their predictive capability. (Author)
@conference{Mavris1999f,
author = {Mavris, Dimitri N and Qiu, Songtao},
title = {An improved process for the generation of drag polars for use in conceptual/preliminary design},
Mavris, D.N. & Roth, B. A methodology for robust design of impingement cooled HSCT combustor liners
1997 AIAA, Aerospace Sciences Meeting & Exhibit, 35th, Reno, NV; UNITED STATES; 6-9 Jan. 1997 inproceedings
Abstract: This paper describes the use of a robust design simulation methodology for the determination of an optimum lean premixed prevaporized combustor liner cooling configuration for a High Speed Civil Transport. The objective of design robustness, as developed at the Georgia Institute of Technology, is to find settings for design parameters which will not only maximize performance, but also minimize the influence of uncertainty on performance. This robust design simulation methodology is formulated here as a very general approach that lends itself to any design problem where uncertainty exists. This general methodology is applied to the design of a combustor liner in order to quantify the effect of cycle parameter and heat transfer coefficient uncertainties on combustor liner metal temperature variance. The results show that for the parameter ranges of interest, impingement hole spacing and thermal barrier coating thickness have the greatest effect on metal temperature variance and are used to find a robust liner configuration. (Author)
@inproceedings{Mavris1997e,
author = {Mavris, Dimitri N and Roth, Bryce},
title = {A methodology for robust design of impingement cooled HSCT combustor liners},
booktitle = {AIAA, Aerospace Sciences Meeting & Exhibit, 35th, Reno, NV; UNITED STATES; 6-9 Jan. 1997},
Conference: AIAA, Aerospace Sciences Meeting & Exhibit, 35th, Reno, NV; UNITED STATES; 6-9 Jan. 1997.
Update: 199701-06.
Mavris, D.N. & Schrage, D.P. Stochastic integrated product and progress development approach to affordable rotorcraft design
1998 Heli Japan 98; Proceedings of the AHS International Meeting on Advanced Rotorcraft Technology and Disaster Relief, Gifu, Japan; UNITED STATES; 21-23 Apr. 1998, pp. 627-637 conference
Abstract: Complex systems embodied in today's rotorcraft will be designed, built, and operated in an era being shaped by an increased emphasis on affordability. We discuss views on the subject and outline the steps taken to develop a new methodology which will allow a true assessment of rotorcraft affordability. The motivation for a paradigm shift in the design evolution process is reviewed which is based on the realization that decisions made during the early design phases are not deterministic in nature and should therefore be handled probabilistically. The authors' current ideas on how to facilitate this paradigm shift from deterministic, performance-based multidisciplinary design to a stochastic formulation whose goal is maximizing affordability are the foci of this paper. Key elements needed to address the affordability of complex systems are reviewed, including a new definition for affordability and an outline of the sources of uncertainty in design. Finally, the elements of a new design methodology which is referred to as the Virtual Stochastic Life-Cycle Design approach are presented and described. (Author)
author = {Mavris, Dimitri N and Schrage, Daniel P},
title = {Stochastic integrated product and progress development approach to affordable rotorcraft design},
Other Numbers: A98-37826 10-01; Contract: NCC2-945; A98-37826 10-01.
Mavris, D.N., Schrage, D.P., Roehl, P.J. & Lee, J.-M. A nacelle-wing integration design methodology for the High Speed Civil Transport
1995 EAC '94 - The supersonic transport of second generation; Proceedings of the 7th European Aerospace Conference, Toulouse, France; FRANCE; 25-27 Oct. 1994, pp. 465-478 conference
Abstract: A methodology is described for the concurrent design of a High Speed Civil Transport nacelle-wing configuration from a structural, aerodynamic, and manufacturing point of view. A Parametric Design Optimization technique is used to rapidly explore the design space, identify the relative influence /importance that each design variable has on the chosen evaluation criteria, and assist in the evaluation of the feasible alternative configurations generated. An overall evaluation criterion for the wing (component level) is defined that captures all important aerodynamic, structural, and manufacturing aspects. During the combined aerodynamic/structural experiment, engine cycle and nacelle parameters are treated as 'noise' factors as they are beyond the control of the aerodynamicist or the structural engineer. In this way the analysis yields a robust design that is as insensitive as possible to the selected noise factors, thus enabling the designer to address the propulsion sizing issues sequentially during the mission and performance sizing of the vehicle. Here, the methodology is described and illustrated through a combined multidisciplinary design experiment. (Author)
author = {Mavris, Dimitri N and Schrage, Daniel P and Roehl, Peter J and Lee, Jae-Moon},
title = {A nacelle-wing integration design methodology for the High Speed Civil Transport},
booktitle = {EAC '94 - The supersonic transport of second generation; Proceedings of the 7th European Aerospace Conference, Toulouse, France; FRANCE; 25-27 Oct. 1994},
publisher = {Paris: Association Aeronautique et Astronautique de France},
Conference: EAC '94 - The supersonic transport of second generation; Proceedings of the 7th European Aerospace Conference, Toulouse, France; FRANCE; 25-27 Oct. 1994.
Mavris, D.N., Soban, D.S. & Largent, M.C. An application of a Technology Impact Forecasting (TIF) method to an uninhabited combat aerial vehicle
Abstract: In today's atmosphere of lower U.S. defense spending and reduced research budgets, determining how to allocate resources for research and design has become a critical and challenging task. The methodology presented in this paper details a comprehensive and structured process in which to explore the effects of technology for a given baseline aircraft. This process, called Technology Impact Forecasting (TIF), involves the creation of a forecasting environment for use in conjunction with defined technology scenarios. The advantages and limitations of the method are discussed, as well its place in an overall methodology used for technology infusion. In addition, the example TIF application used in this paper, that of an Uninhabited Combat Aerial Vehicle, serves to illustrate the applicability of this methodology to a military system. (Author)
@inproceedings{Mavris1999g,
author = {Mavris, Dimitri N and Soban, Danielle S and Largent, Matthew C},
title = {An application of a Technology Impact Forecasting (TIF) method to an uninhabited combat aerial vehicle},
Mavris, D.N., Tai, J. & Schrage, D.P. A multidisciplinary design optimization approach to sizing stopped rotor configurations utilizing reaction drive and circulation control
Abstract: This paper addresses the issues associated with sizing and optimizing a stopped rotor/wing configuration which incorporates a tip jet drive system and Circulation Control devices. In addition, a methodology has been formulated and is presented which forms a foundation upon which a new sizing code capable of handling this unique concept can be developed. Since the subject of this paper deals with a concept that enables relatively uncommon technologies, a review of the physics associated with these concepts is also presented. (Author)
author = {Mavris, Dimitri N and Tai, Jimmy and Schrage, Daniel P},
title = {A multidisciplinary design optimization approach to sizing stopped rotor configurations utilizing reaction drive and circulation control},
Mavris, D.B., Simon & Fernandez, I. Development of a strategic business decision-making environment for commercial jet engine selection
2002 41st AIAA Aerospace Sciences Meeting & Exhibit, Reno, NV; UNITED STATES; 6-9 Jan. 2003 inproceedings
Abstract: In today's business climate, aerospace companies are more than ever in need of rational methods and techniques that provide insights as to the best strategies that may be pursued for increased profitability and risk mitigation. However, the use of subjective, anecdotal decision-making remains prevalent due to the absence of analytical methods capable of capturing and forecasting future needs. Negotiations between airframe and engine manufacturers could benefit greatly from a structured environment that facilitates efficient, rational, decision-making. Creation of such an environment can be developed through a parametric physics-based, stochastic formulation that uses meta-models to expedite the process. This paper describes such an approach in order to demonstrate the types of insights that might be gained as an engine manufacturer tries to forecast the effects of uncertainties and future vehicle requirements on engine related characteristics for the design of a hypothetical regional business jet. Game theory concepts are suggested as a potential means by which one can attach business payoffs to the selection of any engine design point. (Author)
author = {Mavris, Dimitri Briceno, and Simon and Fernandez, Ismael},
title = {Development of a strategic business decision-making environment for commercial jet engine selection},
booktitle = {41st AIAA Aerospace Sciences Meeting & Exhibit, Reno, NV; UNITED STATES; 6-9 Jan. 2003},
Conference: 41st AIAA Aerospace Sciences Meeting & Exhibit, Reno, NV; UNITED STATES; 6-9 Jan. 2003.
Mavris, D.D., Travis & Roth, B. Revolutionary/Unconventional Aeropropulsion Technology Evaluation through Thermodynamic Work Potential - A Revolutionary Aeropropulsion Concepts Program Research Initiative
2002 2002. conference
Abstract: This report is intended as a status report for activities covered May through July 2002 under the auspices of NASA Glenn's Revolutionary Aeropropulsion Concepts (RAC) project. This is the first phase I quarterly report and as such, considerable focus will be given to defining the basic need and motivation driving this research effort. In addition, background research has been ongoing for the past several months and has culminated in considerable information pertaining to the state-of-the-art in work potential analysis methods. This work is described in detail herein. Finally, the proposed analysis approach is described, as are the various ancillary concepts required for its implementation.
author = {Mavris, Dimitri Danner, and Travis and Roth, Bryce},
title = {Revolutionary/Unconventional Aeropropulsion Technology Evaluation through Thermodynamic Work Potential - A Revolutionary Aeropropulsion Concepts Program Research Initiative},
booktitle = {2002.},
Mavris, D.R., Bryce & Macsotai, N. A method for probabilistic sensitivity analysis of commercial aircraft engines
1999 International Society for Air Breathing Engines - ISOABE, ISABE - International Symposium on Air Breathing Engines, 14th, Florence, Italy; INTERNATIONAL ORGANIZATION; 5-10 Sept. 1999 conference
Abstract: The objective of this paper is to illustrate how probabilistic methods can rationally and analytically make design decisions in the presence of uncertainty, with emphasis on the use of probabilistic sensitivities in the aircraft gas turbine engine preliminary design process. A brief review of risk and uncertainty in the engine design process is given, and the role of probabilistic methods is discussed. Probabilistic sensitivity analysis, used in conjunction with response surface methods, is proposed as a computationally efficient method to address defined sources of uncertainty and risk in engine design from a system level perspective. The method outlined is then applied to the analysis of engine component performance uncertainty impact on the performance of a notional four-engine wide-body commercial transport. Uncertainty in engine design parameters is shown to have a direct and quantifiable impact on aircraft system figures of merit such as design range and fuel burn. The methods developed are used to create a set of contour plots showing the behavior of vehicle performance uncertainty over the design space of interest. (Author)
@conference{Mavris1999i,
author = {Mavris, Dimitri Roth, and Bryce and Macsotai, Noel},
title = {A method for probabilistic sensitivity analysis of commercial aircraft engines},
booktitle = {International Society for Air Breathing Engines - ISOABE, ISABE - International Symposium on Air Breathing Engines, 14th, Florence, Italy; INTERNATIONAL ORGANIZATION; 5-10 Sept. 1999},
Conference: International Society for Air Breathing Engines - ISOABE, ISABE - International Symposium on Air Breathing Engines, 14th, Florence, Italy; INTERNATIONAL ORGANIZATION; 5-10 Sept. 1999.
Report Number: ISABE Paper 99-7195.
Mavris, D.R., Bryce & McDonald, R. An Investigation of Applications for Thermodynamic Work Potential Methods - Working Tables and Charts for Estimation of Thermodynamic Work Potential in Equilibrium Mixtures of Jet-A and Air
Abstract: The objective of this report is to provide a tool to facilitate the application of thermodynamic work potential methods to aircraft and engine analysis. This starts with a discussion of the theoretical background underlying these methods, which is then used to derive various equations useful for thermodynamic analysis of aircraft engines. The work potential analysis method is implemented in the form of a set of working charts and tables that can be used to graphically evaluate work potential stored in high-enthalpy gas. The range of validity for these tables is 300 to 36,000 R, pressures between between 0.01 atm and 100 atm, and fuel-air ratios from zero to stoichiometric. The derivations and charts assume mixtures of Jet-A and air as the working fluid. The thermodynamic properties presented in these charts were calculated based upon standard thermodynamic curve fits.
author = {Mavris, Dimitri Roth, and Bryce and McDonald, Rob},
title = {An Investigation of Applications for Thermodynamic Work Potential Methods - Working Tables and Charts for Estimation of Thermodynamic Work Potential in Equilibrium Mixtures of Jet-A and Air},
Report Number: E-16-T42.
McClure, E.K. & Mavris, D.N. Application of Evolutionary Principles to the Selection of Revolutionary Concepts in the Presence of Uncertain Requirements
Abstract: The requirements for which complex systems are designed are rarely the same requirements that those systems actually have to perform once fully developed. Decision makers need to incorporate the probabilistic nature of those requirements into their analysis of revolutionary concepts before concepts are down-selected. The following paper discusses a method developed solely to give decision makers the ability to compare fundamentally different technologies, given an uncertain set of requirements. A cross impact analysis will be used to forecast requirements probabilistically. The "fittest" concepts, or those best suited to meeting the probabilistic set of requirements, will then be identified. The method is then used to evaluate a simple set of requirements for a future commercial transport, and the fitness of a few, simple, revolutionary concepts is evaluated.
@conference{McClure2005,
author = {McClure, Erin K and Mavris, Dimitri N},
title = {Application of Evolutionary Principles to the Selection of Revolutionary Concepts in the Presence of Uncertain Requirements},
McClure, E.E., R, T. & Mavris, D.N. Development of an integrated parametric environment for conceptual hypersonic missile sizing
Abstract: This paper outlines the method by which a graduate missile design team studying at Georgia Tech's Aerospace System Design Laboratory (ASDL) created an environment that would link design parameters to vehicle metrics for the design of a High Speed Standoff Missile. The sizing and synthesis environment parametrically links multiple physics based disciplinary analyses, so that many aspects of the design can be studied simultaneously. That environment was then used to conceptually design a missile that best met the unobtainable requirements set by the customer. The process resulted in the conceptual design of a liquid fueled ramjet cruise missile that was compatible with the Vertical Launch System. The missile cruised at Mach 5, and was capable of striking targets up to 1462 km away. (Author)
@inproceedings{McClure2002,
author = {McClure, Erin Ender, and Tommer R and Mavris, Dimitri N},
title = {Development of an integrated parametric environment for conceptual hypersonic missile sizing},
McDonald, R.A. & Mavris, D.N. Formulation, realization, and demonstration of a process to generate aerodynamic metamodels for hypersonic cruise vehicle design
Abstract: Metamodels representing physics-based engineering codes provide instantaneous access to calibrated tools. Nonlinear transformations extend the capability of metamodels to accurately represent a large design space. Independence, superposition, and scaling properties of the hypersonic engineering method afford an expansive design space without traditional compounding penalties. This one-time investment results in aerodynamic and volumetric metamodels of superior quality and versatility that may be used in many forms throughout early design. As a module, they can be an integral component within a multidisciplinary analysis and optimization package. The aerodynamic polars they produce may provide performance information for mission analysis. Spread-sheet implementations can provide pocket-calculator-like access to explore the design space. Plotting their essence as profiles exposes design trends that may be used in rapid tradeoff studies. This work postulates the procedure, details the execution, and exposes the results of generating uncompromized aerodynamic metamodels for hypersonic cruise vehicle design. (Author)
@conference{McDonald2000,
author = {McDonald, Robert A and Mavris, Dimitri N},
title = {Formulation, realization, and demonstration of a process to generate aerodynamic metamodels for hypersonic cruise vehicle design},
Moffitt, B.A., Bradley, T.H., Parekh, D.E. & Mavris, D. Design and Performance Validation of a Fuel Cell Unmanned Aerial Vehicle
Abstract: This paper describes methods for design of an unmanned aerial vehicle which uses a proton exchange membrane fuel cell as its primary powerplant. The proposed design methods involve the development of empirical and physics-based contributing analyses to model the performance of the aircraft subsystems. The contributing analyses are collected into a design structure matrix which is used to map aircraft performance metrics as a function of design variables over a defined design space. An exhaustive search within the design space is performed to identify optimal design configurations and to characterize trends within the design space so as to inform lower-level design decisions. The results of the design process are used to construct a demonstration fuel cell-powered aircraft. Test results from the demonstration aircraft and its subsystems are compared to predicted results to validate the contributing analyses and improve their accuracy in further design iterations.
@conference{Moffitt2006,
author = {Moffitt, Blake A and Bradley, Thomas H and Parekh, David E and Mavris, Dimitri},
title = {Design and Performance Validation of a Fuel Cell Unmanned Aerial Vehicle},
Classification: 11 Aircraft (MT); 07 Aircraft Propulsion and Power (AH); 73 Fuel Cells (EA).
Accession Number: 200605-11-19797 (MT); A06-07-17697 (AH); 200605-73-25174 (EA).
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH); Electronics & Communication (EA).}
Nam, T., Shih, K.-C. & Mavris, D. Assessment of Environmental and Regulatory Uncertainty Impacts on Propulsion System Design
Abstract: The objective of this paper is to discuss a new structured methodology developed for assisting in engine architecture selection to provide the maximum probability of success of the program under uncertain future environmental regulations. This method integrates a probabilistic analysis technique with the response surface method and an optimization solution technique to enable the designers to rapidly construct the design space and find the optimum design under regulation variations. The response surface method (RSM) approximates the system level responses with a set of quadratic equations as functions of the propulsion system design variables which can capture the primary characteristics of the candidate engine architectures. These equations are fed into the objective function and a series of constraints of an optimization tool. The uncertainty of future regulations is modeled as variations of the regulatory constraint values in the optimization problem. The optimization tool, wrapped with a Monte-Carlo simulation (MCS), solves optimization problems that are set up with randomly selected values of the regulatory constraints. Such a statistical simulation combined with the optimization solution technique provides useful information to the decision maker: the probability of success and estimated ranges of the objective function value for each candidate. A practical demonstration of the method and the accompanying results are given for assessing regulatory uncertainty associated with a Supersonic Business Jet (SBJ) engine development.
@conference{Nam2003,
author = {Nam, Taewoo and Shih, Kai-Chia and Mavris, Dimitri},
title = {Assessment of Environmental and Regulatory Uncertainty Impacts on Propulsion System Design},
Nam, T.S., S, D. & Mavris, D.N. A Generalized Aircraft Sizing Method and Application to Electric Aircraft
Abstract: Internal combustion (IC) engines, which consume hydrocarbon fuels, have dominated the propulsion systems of air-vehicles during a century of aviation history. In the past decade, however, a combination of environmental, technological, and socio-economic changes have stimulated the search for new, alternative sources of power that could challenge the dominance of the IC engine. In particular, fuel cells are increasingly being considered as an alternate power source due to their potential advantages over the traditional power system. Nevertheless, traditional aircraft sizing methods currently employed in the conceptual design phase are not immediately applicable to such revolutionary power drive aircraft designs. Motivated by such deficiencies in state-of-the art sizing methods, a generalized aircraft sizing method has been developed as a solution to this challenge. A brief outline of the method and preliminary results from its application to an electric high altitude long endurance (HALE) configuration are provided in this paper.
author = {Nam, Tacwoo Soban, and Danielle S and Mavris, Dimitri N},
title = {A Generalized Aircraft Sizing Method and Application to Electric Aircraft},
Nam, T.S., S, D. & Mavris, D.N. A Non-Deterministic Aircraft Sizing Method under Probabilistic Design Constraints
Abstract: One of the crucial elements in the conceptual phase of aircraft design is sizing, the goal of which is to find the proper scales of a baseline configuration and a propulsion system that allows the aircraft to achieve the optimum objective function while simultaneously meeting three constraints: balance of power, energy, and volume. In general, both the available power and the required power for the baseline configuration continue to change throughout the preliminary, detail design phases and all the way to flight test. Therefore, the power constraint is probabilistic and stochastic in nature, which is also true for the criteria of energy and volume. Even though such probabilistic natures of the design constraints has been well known in the aerospace community, a deterministic approach to aircraft sizing has been the dominant norm. In this paper the authors present a new non-deterministic method for aircraft sizing that finds the optimum by intelligently allocating appropriate amount of design margins to multiple probabilistic constraints.
author = {Nam, Taewoo Soban, and Danielle S and Mavris, Dimitri N},
title = {A Non-Deterministic Aircraft Sizing Method under Probabilistic Design Constraints},
Classification: 11 Aircraft (MT); 05 Aircraft Design, Testing and Performance (AH); 15 Engineering and Industry (SO).
Accession Number: 200606-11-30732 (MT); A06-05-23063 (AH); 200606-15-34762 (SO).
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH); Solid State & Superconductivity (SO).}
Nam, T.S., S, D. & Mavris, D.N. Power Based Sizing Method for Aircraft Consuming Unconventional Energy
Abstract: Traditionally, most fixed wing and rotary wing aircraft have been powered by internal combustion engines that consume hydrocarbon fuels. Only in a few exceptional designs, such as solar powered air-vehicles, are attempts made to apply alternate energy sources. In the past decade, however, the aerospace community has shown a renewed interest in alternate energy sources for revolutionary propulsion systems. In particular, fuel cells are increasingly being considered as an alternate power source for their potential outstanding advantages over the traditional power system. Nevertheless, traditional aircraft sizing methods are not immediately applicable for such unconventional-energy consuming air-vehicle designs. This paper proposes a generalized aircraft sizing formulation that is also applicable to revolutionary aircraft concepts powered by unconventional energy sources and/or have revolutionary propulsion systems. A power based formulation, which allows easy tracking of energy transformation process from the first power generation to the last propulsive power production, is introduced. Lastly, a generalized aircraft weight estimation formulation that is also valid for unconventional-energy consuming propulsion systems is developed.
@conference{Nam2005a,
title = {Power Based Sizing Method for Aircraft Consuming Unconventional Energy},
Report Number: AIAA Paper 2005-818.
Nixon, J.N. & Mavris, D.N. A multilevel hierarchical approach to technology selection and optimization
Abstract: Advances in performance and increases in revenue are most often facilitated by the development and application of new technologies. Recent efforts in multidisciplinary design have yielded methods for the evaluation and selection of technologies in the presence of uncertainty. All aerospace and industrial power systems are influenced by at least a few parameters, such as air density, pressure, temperature, humidity, etc. For instance, power plant output fluctuates significantly with changes in ambient conditions. In order to evaluate proposed technologies for such a system, a new approach is needed in order to define a framework where operational uncertainties may be quantified and modeled. A robust design methodology has been developed, whereby operating conditions and their impacts can be modeled easily and accurately. An industrial gas turbine power plant is used as an example, and the proposed methodology is integrated with existing methods developed by Mavris and Kirby in order to predict the overall impact of a technology over a year-long period of operation in a specified region. This paper demonstrates how to use this model to refine the design of the technology. Hence, the technology development is treated as a suboptimization problem in which the optimum design settings of the technologies are found. This ambient model is then used to forecast the impact of each technology. Finally, these results are used to select the most promising technology for implementation into the final design. (Author)
@inproceedings{Nixon2002,
author = {Nixon, Janel N and Mavris, Dimitri N},
title = {A multilevel hierarchical approach to technology selection and optimization},
Olson, E.D. & Mavris, D.N. Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction
2006 12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference); Cambridge, MA; USA; 8-10 May 2006 conference
Abstract: An approach was developed which allows for design studies of commercial aircraft using physics-based noise analysis methods while retaining the ability to perform the rapid tradeoff and risk analysis studies needed at the conceptual design stage. A prototype integrated analysis process was created for computing the total aircraft EPNL at the Federal Aviation Regulations Part 36 certification measurement locations using physics-based methods for fan rotor-stator interaction tones and jet mixing noise. The methodology was then used in combination with design of experiments to create response surface equations (RSEs) for the engine and aircraft performance metrics, geometric constraints and takeoff and landing noise levels. In addition, Monte Carlo analysis was used to assess the expected variability of the metrics under the influence of uncertainty, and to determine how the variability is affected by the choice of engine cycle. Finally, the RSEs were used to conduct a series of proof-of-concept conceptual-level design studies demonstrating the utility of the approach. The study found that a key advantage to using physics-based analysis during conceptual design lies in the ability to assess the benefits of new technologies as a function of the design to which they are applied. The greatest difficulty in implementing physics-based analysis proved to be the generation of design geometry at a sufficient level of detail for high-fidelity analysis.
@conference{Olson2006,
author = {Olson, Erik D and Mavris, Dimitri N},
title = {Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction},
booktitle = {12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference); Cambridge, MA; USA; 8-10 May 2006},
Conference: 12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference); Cambridge, MA; USA; 8-10 May 2006.
Olson, E.D. & Mavris, D.N. An integrated low-speed performance and noise prediction methodology for subsonic aircraft
2000 AIAA/CEAS, Aeroacoustics Conference and Exhibit, 6th (21st AIAA Aeroacoustics Conference), Lahaina, HI; UNITED STATES; 12-14 June 2000 conference
Abstract: An integrated methodology has been assembled to compute the engine performance, takeoff and landing trajectories, and community noise levels for a subsonic commercial aircraft. Where feasible, physics-based noise analysis methods were used to make the results more applicable to newer, revolutionary designs and to allow a more direct evaluation of new technologies. The methodology is intended to be used with approximation methods and risk analysis techniques to enable the analysis of a greater number of variable combinations while retaining the advantages of physics-based analysis. Details of the methodology are described, and limited results are presented for a representative subsonic commercial aircraft. (Author)
author = {Olson, E D and Mavris, D N},
title = {An integrated low-speed performance and noise prediction methodology for subsonic aircraft},
booktitle = {AIAA/CEAS, Aeroacoustics Conference and Exhibit, 6th (21st AIAA Aeroacoustics Conference), Lahaina, HI; UNITED STATES; 12-14 June 2000},
Conference: AIAA/CEAS, Aeroacoustics Conference and Exhibit, 6th (21st AIAA Aeroacoustics Conference), Lahaina, HI; UNITED STATES; 12-14 June 2000.
Classification: 11 Aircraft (MT); 71 ACOUSTICS (AH).
Olson, E.D. & Mavris, D.N. Development of response surface equations for high-speed civil transport takeoff and landing noise
Abstract: As an element of a design optimization study of high speed civil transport (HSCT), response surface equations (RSEs) were developed with the goal of accurately predicting the sideline, takeoff, and approach noise levels for any combination of selected design variables. These RSEs were needed during vehicle synthesis to constrain the aircraft design to meet FAR 36, Stage 3 noise levels. Development of the RSEs was useful as an application of response surface methodology to a previously untested discipline. Noise levels were predicted using the Aircraft Noise Prediction Program (ANOPP), with additional corrections to account for inlet and exhaust duct lining, mixer-ejector nozzles, multiple fan stages, and wing reflection. The fan, jet, and airframe contributions were considered in the aircraft source noise prediction. (Author)
title = {Development of response surface equations for high-speed civil transport takeoff and landing noise},
Ordaz, Irian Lee, H., Clark, K., M, D. & Mavris, D.N. Aerodynamic Optimization Using Physics-Based Response Surface Methodology for a Multi-Mission Morphing Unmanned Combat Air Vehicle
Abstract: The most distinguishable advantage of a morphing unmanned combat air vehicle (UCAV) is its ability to adapt to the dissimilar phases of reconnaissance missions involving subsonic loiter and supersonic dash. Effective UCAV configurations are necessarily unconventional, leading to atypical design issues that arise early in the design phases of such an aircraft. As a result, traditional design methods that rely solely on historical data and legacy codes are not viable options. Instead, a physics-based design approach where higher fidelity tools are brought forward into the conceptual design phase is implemented. Response Surface Methodology (RSM) is utilized to effectively bring the physics-based knowledge to the early design stages as well as to allow for the exploration of the design space through a parametric design study. As a first step toward generating the meta-models needed in RSM, geometric models are generated in accordance with a Design of Experiments (DoE) using Rapid Aircraft Modeler (RAM). Drag polars are then created through the use of such linearized codes as VORLAX, BDAP, and AWAVE. These drag polars are regressed to obtain the coefficients for the terms in the equation for total drag. The result of these regressions is a set of Response Surface Equations (RSE's) that parameterize the overall drag in terms of geometry design variables. The aircraft design is then optimized using the RSE's to minimize overall drag. The optimal design represents the most suitable compromise between the hunter and killer modes for the proposed mission.
@conference{Ordaz2004,
author = {Ordaz, Irian Lee, Hun, and and Kyong Clark, and Don M and Mavris, Dimitri N},
title = {Aerodynamic Optimization Using Physics-Based Response Surface Methodology for a Multi-Mission Morphing Unmanned Combat Air Vehicle},
Park, Hyung-Wook Kim, M.-S., Choi, D.-H. & Mavris, D.N. Optimizing the parallel process flow for the individual discipline feasible method
Abstract: For parallel computation-based MDO methodologies such as IDF and CO, a new decomposition method is presented. In this method, the design structure matrix (DSM), which is used to depict the coupling relations among disciplines, is divided into sub-DSM groups, whose number is directly equal to that of parallel computation procedures. Then, their analysis sequences were determined by a genetic algorithm in order to minimize the number of local feedback couplings in each sub-DSM group and the number of global feedback couplings among the sub-DSM groups simultaneously. Finally, two typical MDO problems are decomposed by the proposed method and their local and global feedback couplings are compared with those of the conventional method. These comparisons show that the proposed method gives a nearly 36 percent reduction in the number of couplings compared to that of the conventional method. (Author)
@inproceedings{Park2002,
author = {Park, Hyung-Wook Kim, Min-Soo and and Choi, Dong-Hoon and Mavris, Dimitri N},
title = {Optimizing the parallel process flow for the individual discipline feasible method},
Patel, C.B., Kirby, M.R. & Mavris, D.N. Niched-Pareto Genetic Algorithm for Aircraft Technology Selection Process
Abstract: Design of any complex system entails many objectives to reach and constraints to satisfy. This multi-objective nature of the problem ensures that the technology solution is always a compromise between conflicting objectives. The purpose of this paper is to demonstrate the application of Niched Pareto genetic algorithm as a relatively fast and straightforward method for obtaining technology sets that are distributed along the Pareto frontier in objective space. In this implementation, the genetic algorithm is wrapped around a technology evaluation environment to efficiently evaluate various technology combinations. Some of the major challenges include formulation of Pareto domination tournament and sharing function of Niched Pareto genetic algorithm for a technology selection problem, extracting Pareto front from population of the final generation and visualizing the results.
@conference{Patel2006,
author = {Patel, Chirag B and Kirby, Michelle R and Mavris, Dimitri N},
title = {Niched-Pareto Genetic Algorithm for Aircraft Technology Selection Process},
Pfaender, H., DeLaurentis, D. & Mavris, D. Vehicle Autonomy and Network Topology Trades in Conceptual Design Exploration of UAV Based System-of-Systems
2004 AIAA 3rd "Unmanned Unlimited" Technical Conference, Workshop and Exhibit; Chicago, IL; USA; 20-23 Sept. 2004, pp. 1-9 conference
Abstract: This paper describes the development of a modular object oriented analysis tool that allows the simulation of transportation network architectures. An existing tool is modified and extended to allow a more sophisticated analysis. Lending to its object-oriented design philosophy such extension was possible without a complete overhaul of the analysis tool. Specifically, it allows the comparison of dissimilar network topologies, centralized or distributed optimization and decision-making, and obstacle avoidance. This is illustrated in an example application for a commercial UAV based logistics operation. In this case, interactions of vehicle and network operational variables are examined, as well as comparing different choices for network operational topologies.
@conference{Pfaender2004,
author = {Pfaender, Holger and DeLaurentis, Daniel and Mavris, Dimitri},
title = {Vehicle Autonomy and Network Topology Trades in Conceptual Design Exploration of UAV Based System-of-Systems},
pages = {1-9},
Classification: 04 Aircraft Communications and Navigation (AH).
Pfaender, H., DeLaurentis, D. & Mavris, D.N. An object oriented approach for conceptual design exploration of UAV-based system-of-systems
2003 2nd AIAA "Unmanned Unlimited" Systems, Technologies, and Operations - Aerospace, Land, and Sea Conference, Workshop and Exhibition; San Diego, CA; Sep. 15-18. conference
Abstract: The exploration of an integrated system of UAVs involves the concurrent design of systems (e.g., vehicles), networks, and operational plan. The complexity of the resulting design space even at the conceptual level can easily become unmanageable and finding preferred regions of the combined design space that are not simply a sub-optimal collection of individually optimized entities is a difficult task. Abstraction of the system, therefore, is required and achieved by using an object-oriented approach for modeling the integrated system. Implementing this approach enhances the ability to efficiently search the combined system-of-systems design space. This approach is tested on a UAV-based package delivery architecture, examining tradeoffs between vehicle performance and the network topology for the economic viability of a notional service provider. The object-oriented implementation is found to provide superior modeling flexibility compared to previous approaches.
author = {Pfaender, Holger and DeLaurentis, Daniel and Mavris, Dimitri N.},
title = {An object oriented approach for conceptual design exploration of UAV-based system-of-systems},
booktitle = {2nd AIAA "Unmanned Unlimited" Systems, Technologies, and Operations - Aerospace, Land, and Sea Conference, Workshop and Exhibition; San Diego, CA; Sep. 15-18.},
Conference: 2nd AIAA "Unmanned Unlimited" Systems, Technologies, and Operations - Aerospace, Land, and Sea Conference, Workshop and Exhibition; San Diego, CA; Sep. 15-18, 2003.
Pfaender, H., Lee, Young-Ki Choi, T., Lewe, J.-H. & Mavris, D. Exploration of optimum designs in a criterion space with distributed computer simulation
Abstract: This paper presents the formulation of a simulation-based design approach that identifies a set of optimum aircraft configurations in a criterion space and its implementation in a distributed computing environment. It is applied to a design and selection problem of a new rotorcraft concept to show how engineers are able to support decision makers to arrive at more informed conclusions when conflicting objectives must be considered. Furthermore, the benefits of employing distributed simulation for a computationally demanding task are highlighted and the challenges of synthesizing an efficient and user-friendly distributed computing architecture are also discussed.
@conference{Pfaender2004a,
author = {Pfaender, Holger and Lee, Young-Ki Choi, Taeyun and and Lewe, Jung-Ho and Mavris, Dimitri},
title = {Exploration of optimum designs in a criterion space with distributed computer simulation},
Classification: 60 Computer Operations and Hardware (AH).
Phan, L., Yamaoka, Y. & Mavris, D. Implementation and Benefits of Variable Geometry Wings for a Supersonic Business Jet
Abstract: Due to rapid globalization, the need for a viable and affordable supersonic transport vehicle, which has supersonic overland capability, has gone strong again, especially in the business sector. Several Supersonic Business Jet (SBJ) programs, most of which proposed traditional fixed geometry wing concepts, have been under study, but no successful design has yet been completed. A swing wing, which enables the adaptation of the sweep angle to the flight condition and therefore to achieve better aerodynamic performance, could be a solution to the technical issues involved with the flight at both low speed and high speed regimes. This paper presents the implementation of a swing wing for a supersonic business jet type of aircraft and its potential benefits to the system using integrated modeling and simulation environment based on Response Surface Methodology. It provides comparison results with a fixed-geometry wing vehicle, for the main system level responses and sonic boom.
@conference{Phan2003,
author = {Phan, Leon and Yamaoka, Yohei and Mavris, Dimitri},
title = {Implementation and Benefits of Variable Geometry Wings for a Supersonic Business Jet},
Pouchet, C., Forbes, E., DeLaurentis, D. & Mavris, D. An exploration of a novel approach to aircraft volumetric sizing
Abstract: Aircraft sizing is an iterative process designed to determine the proper size of a vehicle for a particular set of requirements. Most current sizing methods iterate exclusively on fuel weight and leave other considerations, such as volume, as a secondary calculation. However, volumetric demands, especially in emerging innovative vehicle concepts, may begin to take precedence over solely weight-based considerations. This paper describes the volumetric sizing problem and presents research to bring volumetric sizing into the automated design process. The proposed method could enhance current sizing methods while utilizing existing analysis codes without significant source code modification. An object-oriented approach is employed, consistent with the larger research project on a next generation sizing environment in which the particular area of volumetric sizing is one part. Thus, an additional objective is to configure a volumetric sizing process so that the designer will not have to visually verify converged results. The new algorithm has been tested on a unique aircraft concept termed the Quiet Green Transport. Insights on this new approach are described in the context of a previously conducted study of the same aircraft.
@conference{Pouchet2003,
author = {Pouchet, C.F. and Forbes, E.T. and DeLaurentis, D.A. and Mavris, D.N.},
title = {An exploration of a novel approach to aircraft volumetric sizing},
Preisner, L.J., DeLaurentis, D., Mavris, D. & Schrage, D. Application of a technology identification selection and evaluation method for the conceptual design of a VTOL UAV
2002 1st Unmanned Aerospace Vehicles, Systems, Technologies, and Operations Conference and Workshop, Portsmouth, VA; UNITED STATES; 20-23 May 2002 inproceedings
Abstract: Although the current and near-term use of unmanned/uninhabited aerial vehicles (UAVs) in the commercial sphere is both technically difficult and economically nonviable, it is well within the realm of possibility that these circumstances may change in the future. Dramatic advances in the capabilities of such systems have already been demonstrated, and many more shall likely be made as current cutting-edge technologies mature and even newer technologies emerge. This paper is a report on the use of a structured design methodology in executing a system study for the determination of the feasibility of incorporating vertical takeoff and landing UAVs into a commercial package-delivery system. The wide range of concepts and technologies, from basic materials, to vehicle avionics, to propulsion systems (and unknowns about these technologies), that characterize such a study creates a large option space that necessitates the use of innovative design methodologies. The particular methodology employed is presented first, followed by a description of selected steps executed for the application problem. Essentially, a pool of different vehicle configurations and potential technologies were considered. From this pool, a configuration was selected for the platform and the vehicle subsequently was sized using a fuel balance method. Next, emerging technologies primarily in the areas of propulsion and structures were identified. A response surface-based method was used to ascertain their impact on the overall vehicle. Finally, a set of technologies is recommended at the conclusion of the method execution. (Author)
@inproceedings{Preisner2002,
author = {Preisner, L J and DeLaurentis, D and Mavris, D and Schrage, D},
title = {Application of a technology identification selection and evaluation method for the conceptual design of a VTOL UAV},
booktitle = {1st Unmanned Aerospace Vehicles, Systems, Technologies, and Operations Conference and Workshop, Portsmouth, VA; UNITED STATES; 20-23 May 2002},
Conference: 1st Unmanned Aerospace Vehicles, Systems, Technologies, and Operations Conference and Workshop, Portsmouth, VA; UNITED STATES; 20-23 May 2002.
Raczynski, C., ho Lewe, J., Kirby, M. & Mavris, D. Technology portfolio assessments using a gene-correction genetic algorithm
Abstract: This paper discusses a method for optimizing the technology portfolio for a conceptual commercial aircraft. Relationships between technologies and their compatibilities are a major factor during their selection in the initial stages of design. The method discussed herein employs a genetic algorithm approach to incorporate technology incompatibilities early on in the investigation. By only allowing compatible technology sets to be evaluated by the optimizer a reduction in the runtime and the size of the populations over the penalty function approach can be accomplished. The resulting technology portfolio will not only have been optimized to meet the customer requirements but will only contain technologies that are compatible with each other.
@conference{Raczynski2003,
author = {C.M. Raczynski and Jung-ho Lewe and M.R. Kirby and D.N. Mavris},
title = {Technology portfolio assessments using a gene-correction genetic algorithm},
Rallabhandi, S.K. & Mavris, D.N. Aircraft Geometry Design and Optimization for Sonic Boom Reduction
2007 Journal of Aircraft. Jan.-Feb
Vol. 44(1), pp. 35-47 article DOI
Abstract: An improved approach for conceptual supersonic aircraft design is developed and presented. The proposed approach consists of two basic elements: 1) geometry parameterization and discretization, and 2) improved linearized analyses. The geometry generation and discretization scheme creates arbitrarily refined, unstructured geometries quickly and efficiently. Improved linearized tools allow geometric effects to be better captured than existing linearized analysis. The geometry generation and improved linear analyses are coupled to a shape optimization procedure to obtain the geometric shape parameters that simultaneously optimize sonic boom intensity on the ground and lift to drag ratio. Results of this preliminary optimization are presented and discussed.
@article{Rallabhandi2007,
author = {Sriram K. Rallabhandi and Dimitri N. Mavris},
title = {Aircraft Geometry Design and Optimization for Sonic Boom Reduction},
journal = {Journal of Aircraft. Jan.-Feb},
Accession Number: 200703-11-036998 (MT); A06-05-021892 (AH).
Subfile: Mechanical & Transportation Engineering (MT); Aerospace & High Technology (AH).},
doi = {http://dx.doi.org/10.2514/1.20456}
Rallabhandi, S.K. & Mavris, D.N. Sonic Boom Minimization Using Inverse Design and Probabilistic Acoustic Propagation
2006 Journal of Aircraft. Nov.-Dec
Vol. 43(6), pp. 1815-1828 article DOI
Abstract: Using improved linearized tools that operate on unstructured watertight geometries, the accuracy and efficacy of aerodynamic shape optimization in conceptual design stages can be greatly improved. The conventional area distribution method for minimizing sonic boom is theoretically extended by adding additional parameters so that the near-field signature is more accurately represented. The problem of F-function parameters' estimation is reformulated as a gradient-based optimization problem and solved. Sonic boom propagation is carried out in a probabilistic fashion using parametric atmospheric models and statistical techniques. A bilevel pseudoinverse optimization is performed using coarse-grained parallel genetic algorithms to design aircraft that meet low sonic boom requirements under atmospheric uncertainty. The optimization analysis is split into two cycles with multiple conflicting objectives. Results are presented and discussed.
title = {Sonic Boom Minimization Using Inverse Design and Probabilistic Acoustic Propagation},
journal = {Journal of Aircraft. Nov.-Dec},
Rallabhandi, S.K. & Mavris, D.N. A New Approach for Incorporating Computational Fluid Dynamics into Sonic Boom Prediction
Abstract: A new approach for the inclusion of Computational Fluid Dynamics flow solutions into predicting sonic boom signatures is developed. Using existing CFD tools, a near-field flow solution is obtained over the surface of a computational cylinder a certain distance away from the aircraft longitudinal axis. Near-field to far-field multipole matching methodology is performed to calculate the corrected far-field without resorting to unnecessary numerical procedure of calculating the multipole coefficients. The analytical derivation is provided and some results are presented. The results obtained using this approach do not completely match with those obtained using earlier approaches. This is to be investigated in future work.
@conference{Rallabhandi2006a,
title = {A New Approach for Incorporating Computational Fluid Dynamics into Sonic Boom Prediction},
Classification: 02 Aerodynamics (AH).
Rallabhandi, S.K. & Mavris, D.N. Sonic Boom Minimization Using Improved Linearized Tools and Probabilistic Propagation
Abstract: Sonic boom modelling is multidisciplinary involving aerodynamic and aero-acoustics analyses. The near field pressure signature is first obtained using either linearized or non-linear methods. This is then converted into a F-function, which is then propagated to the ground using aero-acoustic routines. Existing linearized methods operate on simple approximations of true geometry. Using improved linearized tools that operate on unstructured water-tight geometries, the accuracy and efficacy of shape optimization can be greatly improved. The sonic boom minimization technique is reformulated as an optimization problem and boom propagation is carried out in a probabilistic fashion. A bi-level reverse optimization is conducted to design aircraft to meet low sonic boom requirements under atmospheric uncertainty.
@conference{Rallabhandi2005,
title = {Sonic Boom Minimization Using Improved Linearized Tools and Probabilistic Propagation},
Rallabhandi, S.K. & Mavris, D.N. Sonic boom modelling under atmospheric uncertainty
Abstract: A conceptual sonic boom prediction environment with linearized analysis methods includes modules to predict the equivalent area due to volume and lift and a module for propagation of the pressure signature to the ground. While exiating linearized tools are simple and produce an acceptable far field signature for most simple geometries, they tend to perform poorly when unconventional configurations are considered. In contrast to the linearized methods, CFD methods consume too much time and are just now trying to make their way into the conceptual-preliminary design stages. The present study attempts to improve the geometric fidelity of configurations being studied in conceptual design. A better geometry representation would lead to improvement in the prediction of the near field signature of the aircraft using linearized methods. Further, pressure perturbations are propagated through parametrically changing atmospheric profiles to capture the effect of the real atmospheric fluctuations. With the above modifications in place, a shape optimization method is employed to obtain suitable configurations for further analysis in the conceptual design stages.
title = {Sonic boom modelling under atmospheric uncertainty},
Rallabhandi, S.K. & Mavris, D.N. An unstructured wave drag code for preliminary design of future supersonic aircraft
2003 33rd AIAA Fluid Dynamics Conference and Exhibit; Orlando, FL; June 23-26. conference
Abstract: In a preliminary design environment, the designer needs to have freedom to quickly evaluate different configurations and come up with the most promising configuration. In the supersonic regime, most linearized codes that are available today can only handle specific shapes and configurations. These codes only aid in optimizing conventional configurations and do not span the entire space of possible shapes, which include revolutionary and unconventional configurations. This paper proposes using a set of GNU libraries and analyses codes to overcome the shortcomings of the legacy codes. It is known that any surface can be discretized into triangles using efficient Delaunay triangulation algorithms. The proposed method involves creating a triangulated aircraft from a generic CAD environment, using the set of geometric libraries and then performing necessary surface operations for the desired result, which in our case is the calculation of the wave drag. Linearized methods for wave drag estimation call for the calculation of the intercepted areas of the aircraft with a Mach cone and the GNU libraries help us in obtaining these areas. Finally, in order to validate the code, the new code is used to compute the wave-drag of a Sears-Haack body and F-16, and the results are compared to the results from AWAVE, the Harris Wave Drag program.
title = {An unstructured wave drag code for preliminary design of future supersonic aircraft},
booktitle = {33rd AIAA Fluid Dynamics Conference and Exhibit; Orlando, FL; June 23-26.},
Conference: 33rd AIAA Fluid Dynamics Conference and Exhibit; Orlando, FL; June 23-26, 2003.
Ran, H. & Mavris, D. A Framework for Determination of the Weak Pareto Frontier Design Solutions under Probabilistic Constraints
Abstract: The design of complex systems such as aircraft or missiles requires the synergy of multiple disciplines. The design quality must ultimately be assessed by multiple criteria that often can not be optimized simultaneously. Therefore, in a less restrictive sense the Weak Pareto Frontier (WPF) in the objective space and the corresponding design solutions must be found because the WPF includes more compromised solutions than the conventional Pareto frontier. Real-world decisions are usually made in a state of uncertainty. Most often the effects of uncertainties are embodied in the probabilistic constraints (PC) that usually must be satisfied jointly. The combination of these issues requires a new framework to combine separately developing multidisciplinary optimization, multi-objective optimization, and joint probability assessment methods together, to solve a joint probabilistic constraint, multi-objective, multidisciplinary optimization problem and find the WPF solutions. The purpose of this paper is to provide such a framework. This framework starts with constructing fast and accurate surrogate models of different disciplinary analyses in order to reduce the computational time and expense to a manageable level and obtain trustworthy probabilities of the PC's and the F. A hybrid method is formed here that consists of the second order response surface methodology (RSM) and the support vector regression method (SVR) capturing the global tendency and local nonlinear behavior, respectively. The parameters of SVR to be pre-specified are selected using practical methods and a modified information criterion that makes use of model fitting error, predicting error, and model complexity information. Then a neighborhood search method based on Monte Carlo simulation is provided to find valid designs that are feasible and consistent for the coupling variables featured in a multidisciplinary design problem. Two schemes have been developed. One scheme finds the WPF by finding a large enough number of valid design solutions such that some WPF solutions are included in them. Another scheme finds the WPF by directly finding the WPF of each consistent design zone that is made up of consistent design solutions. Then the probabilities of the PC's are estimated, and the WPF and corresponding design solutions are found. A simple yet typical aircraft design problem is solved to demonstrate the feasibility of this framework. The results show that the method to select the pre-specified parameters of SVR works well, the hybrid surrogate models are fast and accurate, and both neighborhood search schemes can find the WPF.
@conference{Ran2006,
author = {Ran, Hongjun and Mavris, Dimitri},
title = {A Framework for Determination of the Weak Pareto Frontier Design Solutions under Probabilistic Constraints},
Ran, H. & Mavris, D. Preliminary Design of a 2D Supersonic Inlet to Maximize Total Pressure Recovery
Abstract: This paper provides a method of preliminary design for a two-dimensional, mixed compression, two-ramp supersonic inlet to maximize total pressure recovery and match the mass flow demand of the engine. For an on-design condition, the total pressure recovery is maximized according to the optimization criterion, and the dimensions of the inlet in terms of ratios to the engine face diameter are calculated. The optimization criterion is defined such that in a system of (n-1) oblique shocks and one normal shock in two dimensions, the maximum shock pressure recovery is obtained when the shocks are of equal strength. This paper also provides a method to estimate the total pressure recovery for an off-design condition for the specified inlet configuration. For an off-design condition, conservative estimation of the total pressure recovery is given so that performance of the engine at the off-design condition can be estimated. To match the mass flow demand of the engine, the second ramp angle is adjusted and the open/close schedule of a bypass door is determined. The effects of boundary layer are not considered for the supersonic part of the inlet, however friction and expansion losses are considered for the subsonic diffuser.
title = {Preliminary Design of a 2D Supersonic Inlet to Maximize Total Pressure Recovery},
Raveh, D.E. & Mavris, D.N. Reduced-order models based on CFD impulse and step responses
2001 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 42nd, Seattle, WA; UNITED STATES; 16-19 Apr. 2001 inproceedings
Abstract: Reduced-order models (ROM) based on the Volterra theory for nonlinear systems for the evaluation of nonlinear unsteady aerodynamic forces are presented. The ROMs provide a means for rapid evaluation of frequency-domain generalized aerodynamic forces, which can then be used in traditional flutter analysis schemes to calculate flutter characteristics about nonlinear steady flows. Two ROMs are formulated, an impulse-type ROM that is based on the convolution of ROM kernels with the input signal, and a step-type ROM that is based on convolution with the derivative of the input signal. Linear, first-, and second-order kernels are identified for these two ROMs from direct CFD impulse and step responses. The ROM methodology is demonstrated with the heave and elastic modes of the AGARD 445.6 wing. It was found that the accuracy of the CFD-based impulse response depends on the choice of input amplitude and computational time step, and that the impulse-type kernels are highly sensitive to inaccuracies in the impulse responses used for their identification. The step-type ROM was found to be robust, and resulted in good predictions of direct responses. The introduction of second-order kernels did not significantly improve the predictions, indicating a difficulty in performing true nonlinear identification. The use of first-order step-type ROM offered a significant computational time saving compared to the full CFD frequency response analysis. (Author)
@inproceedings{Raveh2001,
author = {Raveh, Daniella E and Mavris, Dimitri N},
title = {Reduced-order models based on CFD impulse and step responses},
booktitle = {AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 42nd, Seattle, WA; UNITED STATES; 16-19 Apr. 2001},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 42nd, Seattle, WA; UNITED STATES; 16-19 Apr. 2001.
Roehl, P.J., Mavris, D.N. & Schrage, D.P. HSCT wing design through multilevel decomposition
Abstract: A multilevel decomposition approach for the preliminary design of a High Speed Civil Transport Aircraft wing structure is described. The wing design is decomposed into three levels. The top level uses the FLOPS aircraft synthesis program to generate preliminary weights, mission, and performance information. The optimization criterion is productivity expressed by a productivity index for the specified mission. The second level of the system performs a finite-element based structural optimization of the wing box with the help of the ASTROS structural optimization tool. The wing structure is sized subject to strength, buckling, and aeroelastic constraints. The buckling constraint information is supplied by the third level where a detailed buckling optimization of individual skin cover panels is performed. The process is then verified with the help of data from supersonic transport studies performed by U.S. aerospace companies in the 1970s. An HSCT configuration based on the NASA HiSAIR H 24 e is optimized using the multilevel decomposition scheme. The gross weight is reduced by 9.5 percent, and the productivity index, the system level objective function, is increased by 15 percent for the most promising of the configurations analyzed. (Author)
@conference{Roehl1995,
author = {Roehl, Peter J and Mavris, Dimitri N and Schrage, Daniel P},
title = {HSCT wing design through multilevel decomposition},
Roehl, P.J., Mavris, D.N. & Schrage, D.P. Combined aerodynamic and structural optimization of a high-speed civil transport wing
1995 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 36th and AIAA/ASME Adaptive Structures Forum, New Orleans, LA, Technical Papers. Pt. 1; UNITED STATES; 10-13 Apr. 1995, pp. 548-557 conference
Abstract: A combined procedure for the aerodynamic and structural optimization of a high-speed civil transport wing is presented. The primary goal of the procedure is the determination of the jig shape of the wing necessary so that it deforms into its optimum shape in cruise flight. The wing twist and camber distribution is optimized for the cruise condition using WINGDES, a code based on a linearized potential flow solution for zero-thickness lifting surfaces. The structural design is decomposed into three levels. The top level uses the FLOPS aircraft synthesis program to generate preliminary weights, mission, and performance information. The optimization criterion is productivity expressed by a productivity index for the specified mission. The second level of the system performs a finite-element-based structural optimization of the wing box with the help of the ASTROS structural optimization tool. The wing structure is sized subject to strength, buckling, and aeroelastic constraints. The buckling constraint information is supplied by the third level where a detailed buckling optimization of individual skin cover panels is performed. The Georgia Tech HSCT baseline aircraft is presented and the resulting optimum wing structure, cruise, and jig shapes are explained. (Author)
@conference{Roehl1995a,
title = {Combined aerodynamic and structural optimization of a high-speed civil transport wing},
booktitle = {AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 36th and AIAA/ASME Adaptive Structures Forum, New Orleans, LA, Technical Papers. Pt. 1; UNITED STATES; 10-13 Apr. 1995},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 36th and AIAA/ASME Adaptive Structures Forum, New Orleans, LA, Technical Papers. Pt. 1; UNITED STATES; 10-13 Apr. 1995.
Rohl, P.J., Mavris, D.N. & Schrage, D.P. A multilevel wing design procedure centered on the ASTROS structural optimization program
1994 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 5th, Panama City Beach, FL, Technical Papers. Pt. 2; UNITED STATES; 7-9 Sept. 1994, pp. 1377-1387 conference
Abstract: A multilevel decomposition approach for the preliminary design of a High Speed Civil Transport Aircraft wing structure is described. The wing design is decomposed into three levels. The top level uses the FLOPS aircraft synthesis program to generate preliminary weights, mission, and performance information. The optimization criterion is productivity expressed by a productivity index for the specified mission. The second level of the system performs a finite-element based structural optimization of the wing box with the help of the ASTROS structural optimization tool. The wing structure is sized subject to strength, buckling, and aeroelastic constraints. The buckling constraint information is supplied by the third level where a detailed buckling optimization of individual skin cover panels is performed. The integration of the panel buckling procedure into the structural optimization system is described in detail together with initial results that were obtained for an HSCT baseline configuration based on the NASA HiSAIR project. (Author)
@conference{Rohl1994,
author = {Rohl, Peter J and Mavris, Dimitri N and Schrage, Daniel P},
title = {A multilevel wing design procedure centered on the ASTROS structural optimization program},
Roth, B.A. & Mavris, D.A. Generalized model for vehicle thermodynamic loss management.
Vol. 40(1), pp. 62-69 article
Abstract: A general-purpose loss management model to account for the usage of thermodynamic work potential in vehicles of any type is developed. The key to accomplishing this is the creation of a differential representation for vehicle loss as a function of operating condition. This differential model is then integrated through mission time to obtain an analytical estimate for total usage of work potential consumed by each loss mechanism present during vehicle operation. This leads to a better understanding of how the work potential initially present in the mission fuel is partitioned among all loss mechanisms present during the vehicle's operation. This result can also be used in conjunction with cost accounting to gain a better understanding of underlying drivers on vehicle manufacturing and operating costs. The method is demonstrated for the analysis of a lightweight fighter aircraft. (Author)
@article{Roth2003,
author = {Roth, B A and Mavris, D A},
title = {Generalized model for vehicle thermodynamic loss management.},
Illustrations: Graphs.
Roth, B.A. & Mavris, D.N. Comparison of thermodynamic loss models suitable for gas turbine propulsion
2001 Journal of Propulsion and Power
Abstract: The description of several figures of merit for estimation of loss in work potential based on the second law of thermodynamics and evaluation of their relative merits for propulsion system analysis and design are the objectives. The loss figures of merit examined are exergy, gas horsepower, and thrust work potential. Definitions and simplified expressions for evaluating each are presented and related via contours on a Temperature-Entropy diagram, and a working comparison is provided by way of a pedagogical example using the J-79 turbojet engine. It is shown that thrust work potential is a special case of gas horsepower, which is in turn a special case of exergy. Based on these results, a general taxonomy is suggested to classify the various work potential figures of merit. The results of this analysis are then used to draw inferences as to what applications each work potential figure of merit is best suited, the general conclusion being that they are complimentary, with each figure of merit being well suited to a particular application. Finally, a general work exclusion principal is suggested as a guide to which of the various loss figures of merit is most appropriate for a given application. (Author)
author = {Roth, Bryce A and Mavris, Dimitri N},
title = {Comparison of thermodynamic loss models suitable for gas turbine propulsion},
journal = {Journal of Propulsion and Power},
Classification: 77 THERMODYNAMICS AND STATISTICAL PHYSICS (AH).
Roth, B.A. & Mavris, D.N. A generalized model for vehicle thermodynamic loss management and technology concept evaluation
Abstract: The objective of this paper is to develop a generalized loss management model to account for the usage of thermodynamic work potential in vehicles of any type. The key to accomplishing this is creation of a differential representation for vehicle loss as a function of operating condition. This differential model is then integrated through time to obtain an analytical estimate for total usage (and loss) of work potential consumed by each loss mechanism present during vehicle operation. The end result of this analysis is a better understanding of how the work potential initially present in the fuel, batteries, etc. is partitioned among all losses relevant to the vehicle's operation. The loss partitioning estimated from this loss management model can be used in conjunction with cost accounting systems to gain a better understanding of underlying drivers on vehicle manufacturing and operating costs. In addition, loss management models are useful for evaluation of technology models during the preliminary phases of design because they provide a common basis to measure the impact of disparate technologies. (Author)
@conference{Roth2000,
title = {A generalized model for vehicle thermodynamic loss management and technology concept evaluation},
Classification: 80 Management and Marketing (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Roth, B.A. & Mavris, D.N. A comparison of thermodynamic loss models applied to the J-79 turbojet engine
2000 AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 36th, Huntsville, AL; UNITED STATES; 16-19 July 2000 inproceedings
Abstract: The objective of this paper is to clarify the relationships between various work loss figures of merit that have been proposed for application to gas turbine propulsion. The intent is to provide a working comparison by way of a pedagogical example using the J-79 turbojet engine. The results of this analysis are then used to draw inferences as to what applications each work potential figure of merit is best suited. Finally, a general 'work exclusion principle' is suggested as a guide to which of the various loss figures of merit is most appropriate for a given application. (Author)
@inproceedings{Roth2000a,
title = {A comparison of thermodynamic loss models applied to the J-79 turbojet engine},
Roth, B.A. & Mavris, D.N. A comparison of thermodynamic loss models suitable for gas turbine propulsion - Theory and taxonomy
Abstract: The objective of this paper is to describe several figures of merit for estimation of loss in work potential based on the second law of thermodynamics and to evaluate their relative merits for propulsion system analysis and design. The loss figures of merit examined are exergy, gas horsepower, stream thrust, and thrust work potential. Definitions and simplified expressions for evaluating each are presented, and the relationships between these four metrics are expressed via contours on a T-S diagram. A general taxonomy classifying the various work potential figures of merit is suggested. The results indicate that each method is well suited to a particular type of application, with the most appropriate choice of loss figure of merit depending on the particular application. Finally, the thrust work potential is shown to be a special case of gas horsepower, which is, in turn, a special case of exergy. (Author)
@conference{Roth2000b,
title = {A comparison of thermodynamic loss models suitable for gas turbine propulsion - Theory and taxonomy},
Classification: 61 Design Principles (MT); 77 THERMODYNAMICS AND STATISTICAL PHYSICS (AH).
Roth, B., German, B., Mavris, D. & Macsotai, N. Adaptive selection of engine technology solution sets from a large combinatorial space
2001 AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt Lake City, UT; UNITED STATES; 8-11 July 2001 inproceedings
Abstract: This paper describes a method to assist in selecting technology concepts from among a pool of candidates so that the resulting concepts yield the best compromise between conflicting objectives, such as design performance and technology risk. The heart of this method is a unique technology impact forecasting environment that is used in conjunction with a genetic algorithm as a tool to efficiently explore the technology combinatorial space. The technique is applied to a commercial turbofan engine technology selection problem of practical interest. A pool of 40 technology concepts is proposed and evaluated, the objective being to determine which subset of technologies is the best candidate to go forward into development given conflicting objectives on performance, engine manufacturing cost, and design risk. (Author)
author = {Roth, Bryce and German, Brian and Mavris, Dimitri and Macsotai, Noel},
title = {Adaptive selection of engine technology solution sets from a large combinatorial space},
booktitle = {AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt Lake City, UT; UNITED STATES; 8-11 July 2001},
Conference: AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt Lake City, UT; UNITED STATES; 8-11 July 2001.
Roth, B., Graham, M., Mavris, D. & Macsotai, N. Adaptive selection of pareto optimal engine technology solution sets
2002 ICAS 2002(2002-594.1)23rd International Congress of Aeronautical Sciences conference
Abstract: Successful selection of propulsion system technologies for development and incorporation into new engine designs requires careful balance among many competing design objectives (i.e. performance, cost, risk, etc.). One seldom has sufficient development resources available to fully explore all promising concepts and must therefore choose a few technologies that show the greatest promise to meet program objectives. This paper describes a method of selecting optimal combinations of engine technologies. This method employs a technology impact forecasting environment in conjunction with genetic algorithms to find Pareto-optimal technology solution sets. These results are illustrated using Technology State Transition Diagrams to show how technologies move into and out of the Pareto-optimal sets. An edge search procedure is introduced as a means to efficiently characterize the objective space, the results of which are presented in the form of ternary plots. These plots show how technologies benefit multiple (often-conflicting) objectives and help find robust or compromise technology combinations. Finally, these methods are applied to select engine technology combinations for a commercial engine system of current interest.
author = {Roth, B. and Graham, M. and Mavris, D. and Macsotai, N.},
title = {Adaptive selection of pareto optimal engine technology solution sets},
number = {2002-594.1},
Roth, B. & Mavris, D. Method for propulsion technology impact evaluation via thermodynamic work potential.
Abstract: Recent developments in thermodynamic work potential methods based on the second law of thermodynamics are enabling new and innovative approaches to systems design. These methods can assist designers in quantifying the impact of new technology in a comprehensive and consistent manner. Work potential methods allow the creation of a truly unified picture of aerothermodynamic and weight benefits associated with a given technology and, furthermore, allow the explicit calculation of each individual contributing factor constituting that impact. The basic theory for technology evaluation via work potential, how it can be directly related to vehicle mass properties (fuel weight), and a demonstration of its application on a classic propulsion technology selection problem applied to the Northrop F-5E aircraft are described. (Author)
@article{Roth2003a,
author = {Roth, B and Mavris, D},
title = {Method for propulsion technology impact evaluation via thermodynamic work potential.},
Classification: 11 Aircraft (MT); 77 THERMODYNAMICS AND STATISTICAL PHYSICS (AH).
Roth, B. & Mavris, D. Technology portfolio assessments using a modified genetic algorithm approach
Abstract: This paper presents a method employing genetic algorithms in conjunction with advanced technology analysis methods. This method is intended to assist decision makers in selection technology concepts for incorporation into future products, especially for those situations where there are many technology options available. Emphasis is placed here on developing the means by which technology incompatibilities can be modeled and on examination of how these incompatibilities impact the final solution. This is then demonstrated for a set of 36 aircraft technologies of current interest. System figures of merit include environmental impact, vehicle performance, and economic cost. (Author)
author = {Roth, Bryce and Mavris, Dimitri},
title = {Technology portfolio assessments using a modified genetic algorithm approach},
Classification: 63 CYBERNETICS (AH).
Roth, B. & Mavris, D. Commercial engine architecture selection in the presence of uncertainty and evolving requirements
2001 ISOABE, ISABE - International Symposium on Air Breathing Engines, 15th, Bangalore, India; INTERNATIONAL ORGANIZATION; 3-7 Sept. 2001 conference
Abstract: The objective of this paper is to discuss a few challenges foreseeable for future aircraft engine designs and briefly survey ongoing research that addresses these challenges. Emphasis is placed on methods for selecting commercial engine architectures. Four fundamental needs are identified and discussed at length: uncertainty in the design process, strategic business decisions in the context of engine design, complexity of future propulsion systems, and integration of new technologies into next-generation products. Probabilistic techniques are suggested as an analytical means to quantify the impact of uncertainty and to allow for uncertainty-mitigating decisions in the design process. Advanced engineering models in conjunction with ideas from complexity theory and game theory are a possible means of addressing the larger strategic business decisions as they pertain to architecture selection. Thermodynamic work potential methods are proposed as a basis for dealing with increased complexity. Finally, the role of technology identification, evaluation, and selection methods in engine technology studies is discussed. (Author)
title = {Commercial engine architecture selection in the presence of uncertainty and evolving requirements},
booktitle = {ISOABE, ISABE - International Symposium on Air Breathing Engines, 15th, Bangalore, India; INTERNATIONAL ORGANIZATION; 3-7 Sept. 2001},
Conference: ISOABE, ISABE - International Symposium on Air Breathing Engines, 15th, Bangalore, India; INTERNATIONAL ORGANIZATION; 3-7 Sept. 2001.
Report Number: ISABE-2001-1169.
Classification: 62 Theoretical Mechanics and Dynamics (CE); 11 Aircraft (MT); 7 AIRCRAFT PROPULSION AND POWER (AH).
Roth, B. & Mavris, D. Work availability perspective of turbofan engine performance
Abstract: This paper presents a work availability perspective on the thermodynamic performance of the turbofan engine and contrasts this with the classic presentation, which describes performance based primarily on cycle efficiency. It is shown that the availability perspective leads to a more fundamental understanding of the basic problem, this being to maximize the conversion of work potential stored in the fuel into useful work output. The discussion specifically addresses the impact of primary turbofan cycle parameters on usage and loss of work potential. It is shown that cycle pressure ratio governs exhaust heat losses, turbine inlet temperature governs non-equilibrium combustion losses, and fan pressure ratio governs loss due to residual exhaust kinetic energy. Finally, simplified loss calculation methods applicable to any turbofan engine are presented, and the method is applied to the analysis of cycle losses in the Northrop F-5E propulsion system. (Author)
@inproceedings{Roth2001c,
title = {Work availability perspective of turbofan engine performance},
Roth, B. & Mavris, D. Technology evaluation via loss management models formulated in terms of vehicle weight, or whither a scheme for vehicle fuel weight accountability?
Vol. 60(1)Weight Engineering (0583-9270), pp. 53-77 conference
Abstract: The intent of this paper is to formulate a method for quantifying thermodynamic performance in terms of mission fuel chargeable to each thermodynamic loss mechanism. This is then used in conjunction with known vehicle zero fuel weight groups to estimate the gross weight chargeable to each functional component of the vehicle. The results show that chargeable vehicle gross weight can be used as a common figure of merit linking mass properties and performance aspects of vehicle design. This method is then demonstrated for a Northrop F-5E aircraft, and the fuel weight breakdown is analytically calculated for the design mission. The results of this analysis show that 37.3 percent of the F-5E subsonic mission fuel requirement is due to propulsion system losses, 36.8 percent is chargeable to aerodynamic drag, and 24.3 percent is chargeable to vehicle empty weight. This translates into a chargeable fuel cost of roughly 173.90, 171.76, and 113.53 dollars for each of these three loss mechanisms, respectively. Finally, the usefulness of this technique as a means of technology evaluation is considered. The strengths of this method are that it allows quantification of both weight and performance aspects of technology benefits in a single figure of merit, and also enables one to ascertain the benefits of individual technologies even when applied as part of a suite of technologies. (Author)
@conference{Roth2000c,
title = {Technology evaluation via loss management models formulated in terms of vehicle weight, or whither a scheme for vehicle fuel weight accountability?},
booktitle = {Weight Engineering (0583-9270)},
Conference: SAWE, Annual Conference, 59th; St. Louis, MO; UNITED STATES; 5-7 June 2000.
Other Numbers: Contract: DMI 9734234.
Classification: 62 Theoretical Mechanics and Dynamics (CE); 11 Aircraft (MT); 5 AIRCRAFT DESIGN, TESTING AND PERFORMANCE (AH).
Roth, B. & Mavris, D. Analysis of advanced technology impact on HSCT engine cycle performance
1999 AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 35th, Los Angeles, CA; UNITED STATES; 20-24 June 1999 conference
Abstract: The objective of this paper is to describe and apply methods that could assist the propulsion system designer in the evaluation and selection of propulsion technologies. The focus here is on the aerothermodynamic aspects of the problem, particularly estimation of engine internal losses. This is accomplished by leveraging developments in second law analysis methods that are able to quantify the theoretical work potential as well as the loss in work potential. Two basic methods, exergy and 'gas horsepower', are described and the suitability of each for propulsion systems analysis is discussed. These are used to develop a simple approach to engine internal loss estimation, and are then demonstrated on several basic technology scenarios for a High Speed Civil Transport Propulsion System. The various sources of loss for each concept are examined in detail, and the results for the two methods are compared. (Author)
title = {Analysis of advanced technology impact on HSCT engine cycle performance},
booktitle = {AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 35th, Los Angeles, CA; UNITED STATES; 20-24 June 1999},
Conference: AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 35th, Los Angeles, CA; UNITED STATES; 20-24 June 1999.
Roth, B., Mavris, D. & Elliott, D. A probabilistic approach to UCAV engine sizing [Unmanned Combat Aerial Vehicle]
1998 AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 34th, Cleveland, OH; UNITED STATES; 13-15 July 1998 conference
Abstract: This paper describes a probabilistic approach to aircraft engine thrust sizing which is intended to assist the designer in making decisions during the very early stages of the design process, when the operational concept is still evolving and uncertainty abounds (in both mission requirements and technological capability). The focus of this paper is on analysis of mission uncertainty, such as that due to ambiguity in payload, range, maneuver requirements, etc. and its impact on propulsion system sizing. Several analysis tools appropriate for probabilistic thrust sizing are discussed, and one is applied to the probabilistic thrust sizing of an unmanned combat aerial vehicle designed for a deep-strike mission. The result is a distribution for thrust which can then be used in combination with the core engine design space to estimate the design's probability of successfully meeting the thrust requirements. Finally, a method for tracking mission uncertainty as the requirements develop is described and illustrated for the unmanned combat aerial vehicle (UCAV) example. (Author)
author = {Roth, Bryce and Mavris, Dimitri and Elliott, Don},
title = {A probabilistic approach to UCAV engine sizing [Unmanned Combat Aerial Vehicle]},
booktitle = {AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 34th, Cleveland, OH; UNITED STATES; 13-15 July 1998},
Conference: AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 34th, Cleveland, OH; UNITED STATES; 13-15 July 1998.
Roth, B. & Mavris, D.N. A method for propulsion technology impact evaluation via thermodynamic work potential
Abstract: Recent developments in thermodynamic work potential (exergy) methods based on the second law of thermodynamics are enabling new and innovative approaches to systems design that have not been possible in the past. These methods allow the creation of a truly unified picture of aerothermodynamic and weight benefits associated with a given technology, and further allow the explicit calculation of each individual contributing factor constituting that impact. This paper describes the basic theory for technology evaluation via work potential, shows how it can be directly related to vehicle mass properties (weight), and demonstrates its application on a classic propulsion technology selection problem applied to the Northrop F-5E aircraft. A parametric family of engine cycle/technology concepts based on the J85-GE21 engine of the Northrop F-5E aircraft is defined, and loss management methods are applied to the analysis and quantification of the technology impact for the F-5E/J85 engine airframe combinations. The result is a more detailed descripton of cycle technology impact than has been possible in the past. (CSA)
@conference{Roth2000d,
author = {Roth, Bryce and Mavris, Dimitri N},
title = {A method for propulsion technology impact evaluation via thermodynamic work potential},
Roth, B.M., Rob & Mavris, D. A method for thermodynamic work potential analysis of aircraft engines
Abstract: The objective of this paper is to provide a tool to facilitate the application of thermodynamic work potential methods for aircraft and engine analysis. This starts with a discussion of the theoretical background underlying these methods, which is then used to derive various equations useful for thermodynamic analysis of aircraft engines. The work potential analysis method is implemented in the form of a set of working charts and tables than can be used to graphically evaluate work potential stored in high-enthalpy gas. The range of validity for these charts is 300 to 36,000 R, pressures between 0.01 and 100 atm and fuel-air ratios from zero to stoichiometric. The derivations and charts assume mixtures of Jet-A and air as the working fluid. The thermodynamic properties presented in these charts were calculated based upon standard thermodynamic curve fits. (Author)
@inproceedings{Roth2002b,
author = {Roth, Bryce McDonald, and Rob and Mavris, Dimitri},
title = {A method for thermodynamic work potential analysis of aircraft engines},
Roth, D.B. & Mavris, D. Evaluation and Selection of Technology Concepts for a Hypersonic High Speed Standoff Missile
Abstract: This paper describes the application of a method for technology concept selection to the design of a hypersonic high-speed standoff missile capable of achieving pin-point strike of long-range targets with very short dwell times, such as mobile missile launchers. The primary strengths of this method are its ability to systematically enumerate and organize a wide variety of design alternatives in a simple and elegant manner, and its ability to facilitate concept selection for multi-attribute problems. The high-speed standoff missile is used as a model for application of this technique due to the multi-attribute nature of the problem and the stringent nature of the requirements. These requirements include a 1,500 lb launch weight, 500nmi range, less than 10 minute time to target, and a unit cost of less than $300,000. The first step in this process was to assemble a set of configuration and technology options for consideration. From these, a set of eight concepts were synthesized, evaluated, and down-selected to two alternatives: an advanced solid rocket concept and a ramjet concept. These two designs were evaluated in detail for cost, performance, lethality, and effectiveness. The results were then used in conjunction with the TOPSIS multi-attribute evaluation technique to make a final selection.
author = {Roth, Dr Bryce and Mavris, D},
title = {Evaluation and Selection of Technology Concepts for a Hypersonic High Speed Standoff Missile},
Notes: RECON no. 20010090281.
Scharl, J. & Mavris, D. Building parametric and probabilistic dynamic vehicle models using neural networks
2001 AIAA Modeling and Simulation Technologies Conference and Exhibit, Montreal, Canada; UNITED STATES; 6-9 Aug. 2001 conference
Abstract: During the past decade, the aircraft vehicle design process has undergone a major shift of focus from pure performance towards a balance between vehicle characteristics and cost, namely, affordability. In addition, accelerated advances in computing technology have helped render a complete parametric and probabilistic design process feasible. All of these changes have allowed more knowledge to be brought earlier into the design process, which helps designers make more informed and therefore better decisions earlier in the design process. Computing power now allows extensive physics-based vehicle modeling early in the design cycle. A full non-linear 6-DOF parametric dynamic vehicle model should be attainable as early as the conceptual design phase. Such a vehicle model would help clarify the effects of design variables on vehicle characteristics and operation through analysis and simulation. Furthermore, probabilistic design methods enable the proper treatment of uncertainty and fidelity inherent in such a model. This paper formulates a framework to arrive at a conceptual non-linear 6-DOF parametric and probabilistic dynamic vehicle model based on neural networks. (Author)
@conference{Scharl2001,
author = {Scharl, Julien and Mavris, Dimitri},
title = {Building parametric and probabilistic dynamic vehicle models using neural networks},
booktitle = {AIAA Modeling and Simulation Technologies Conference and Exhibit, Montreal, Canada; UNITED STATES; 6-9 Aug. 2001},
Conference: AIAA Modeling and Simulation Technologies Conference and Exhibit, Montreal, Canada; UNITED STATES; 6-9 Aug. 2001.
Classification: 63 Mathematics and Computation (CE); 11 Aircraft (MT); 63 CYBERNETICS (AH).
Scharl, J.M., N, D. & Burdun, I.Y. Use of flight simulation in early design - Formulation and application of the virtual testing and evaluation methodology
Abstract: In current design practices, safety, operational, and handling criteria are often overlooked until late design stages due to the difficulty in capturing such criteria early enough in the design cycle and in the presence of limited and uncertain knowledge. Virtual (flight) testing and evaluation, based on autonomous modeling and simulation, is proposed as a solution to this shortcoming. The methodology enables one to evaluate vehicle behavior in relatively complex situations through a series of specific flight scenarios. Bringing this methodology to conceptual design requires the creation of an automatic link between the design data base and the autonomous flight simulation environment. This paper describes the creation of such a link and an implementation of the virtual testing and evaluation methodology with the use of an advanced design concept. (Author)
author = {Scharl, Julien Mavris, and Dimitri N and Burdun, Ivan Y},
title = {Use of flight simulation in early design - Formulation and application of the virtual testing and evaluation methodology},
Schrage, D.P. & Mavris, D. Technology for affordability - How to define, measure, evaluate, and implement it?
Vol. 2AHS, Annual Forum, 50th, Washington, DC, Proceedings; UNITED STATES; 11-13 May 1994, pp. 1039-1053 conference
Abstract: In recent years, the stated emphasis for new aircraft development programs has been that affordability must be the driving factor. It has also been stressed that, since the Life Cycle Cost (LCC) of an aircraft and of other complex systems gets locked-in early, it is the conceptual and preliminary design phases where affordability issues and technologies must be addressed. However, experience has indicated that there are communication gaps between designers, technologists, and cost analysts when addressing affordability. In addition, LCC models are often inadequate, not user friendly, or do not provide both the top-down and bottom-up sensitivity analysis capabilities to relate economic considerations to key design parameters when making system, component, or part design trades. This paper sheds some light on technology for affordability and provides a methodology on how to define, measure, evaluate, and implement it. (Author)
@conference{Schrage1994,
author = {Schrage, Daniel P and Mavris, Dimitri},
title = {Technology for affordability - How to define, measure, evaluate, and implement it?},
booktitle = {AHS, Annual Forum, 50th, Washington, DC, Proceedings; UNITED STATES; 11-13 May 1994},
Conference: AHS, Annual Forum, 50th, Washington, DC, Proceedings. Vol. 2; UNITED STATES; 11-13 May 1994.
Schrage, D.P., Mavris, D., Virasak, J. & Kim, Ho-sik May, W.R. Impact of performance requirements on rotorcraft configuration selection
Vol. 2European Rotorcraft Forum, 20th, Proceedings; NETHERLANDS; 4-7 Oct. 1994 to 50-13, pp. 50-1 conference
Abstract: For conventional helicopters of the past the hover requirements, in terms of altitude, temperature, and Vertical Rate of Climb (VROC), were often the driving considerations for vehicle design synthesis and configuration selection with the forward flight speed requirements often being a fallout or off-design consideration. However, in recent years as rotorcraft have demonstrated their ability to perform a variety of military and commercial missions, vehicle design synthesis and rotorcraft configuration selection must be based on the driving performance requirements. This paper will address the impact of performance requirements on rotorcraft configuration selection using the requirements identified in the 10th Annual American Helicopter Society (AHS) Student Design Competition. (Author)
@conference{Schrage1994a,
author = {Schrage, Daniel P and Mavris, Dimitri and Virasak, Jacques and Kim, Ho-sik May, Wade R},
title = {Impact of performance requirements on rotorcraft configuration selection},
booktitle = {European Rotorcraft Forum, 20th, Proceedings; NETHERLANDS; 4-7 Oct. 1994 to 50-13},
publisher = {Amsterdam, Netherlands: National Aerospace Laboratory},
pages = {50-1},
Conference: European Rotorcraft Forum, 20th, Proceedings. Vol. 2; NETHERLANDS; 4-7 Oct. 1994.
Schrage, D.P. & Mavris, D.N. Recomposition - The other half of the MDO equation
1997 Multidisciplinary design optimization - State of the art; Proceedings of the ICASE/NASA Langley Workshop, Hampton, VA; UNITED STATES; 13-16 Mar. 1995, pp. 432-447 conference
Abstract: This paper describes the newly developed Georgia Tech Aerospace Systems Design Laboratory (ASDL) IPPD (Integrated Product and Process Development) methodology and the way it is implemented. This methodology consists of four key elements: a top down decision support process, systems engineering methods and tools, quality engineering methods and tools, and a computer integrated environment. A detailed example is provided on how it is being utilized to assist NASA and the commercial transport industry in developing and evaluating metrics for the High Speed Civil Transport (HSCT). Examples for rotorcraft and other aircraft are also discussed. The paper will also provide arguments as to why, for all aerospace systems, and in particular rotorcraft, IPPD through robust design simulation is the key for affordable systems. (Author)
author = {Schrage, Daniel P and Mavris, Dimitri N},
title = {Recomposition - The other half of the MDO equation},
booktitle = {Multidisciplinary design optimization - State of the art; Proceedings of the ICASE/NASA Langley Workshop, Hampton, VA; UNITED STATES; 13-16 Mar. 1995},
publisher = {Philadelphia, PA: SIAM - Society for Industrial and Applied Mathematics},
Conference: Multidisciplinary design optimization - State of the art; Proceedings of the ICASE/NASA Langley Workshop, Hampton, VA; UNITED STATES; 13-16 Mar. 1995.
Schrage, D.P. & Mavris, D.N. Rotorcraft system design for affordability through Integrated Product/Process Development (IPPD)
Vol. 1European Rotorcraft Forum, 22nd, Brighton, United Kingdom, Proceedings; UNITED KINGDOM; 17-19 Sept. 1996.1-2.16, pp. 2 conference
Abstract: The life cycle cost (LCC) for complex systems, such as rotorcraft, gets locked in early during the design and development process. One reason for this situation is that many early product design decisions are made by the aircraft manufacturer/designer during conceptual design, before they are passed on to subcontractors /suppliers/vendors for design at the component/subcomponent/part level. This approach results in a time lag for conceptual design being conducted by the various participants. This serial product decomposition approach has resulted in high performance and capable systems, but not always the most affordable or competitive system. This traditional approach assumes that minimizing weight reduces cost, even LCC. IPPD is being tauted as a new approach, where parallel product/process (performance/cost) design tradeoffs are conducted. This paper presents how system design for affordability through IPPD, including rotorcraft, is being development in the Georgia Tech Aerospace System's Design Laboratory. (Author)
title = {Rotorcraft system design for affordability through Integrated Product/Process Development (IPPD)},
booktitle = {European Rotorcraft Forum, 22nd, Brighton, United Kingdom, Proceedings; UNITED KINGDOM; 17-19 Sept. 1996.1-2.16},
publisher = {London: Royal Aeronautical Society},
Conference: European Rotorcraft Forum, 22nd, Brighton, United Kingdom, Proceedings. Vol. 1; UNITED KINGDOM; 17-19 Sept. 1996.
Schrage, D.P. & Mavris, D.N. Integrated product/process design/development (IPPD) through robust design simulation - The key for affordable systems
Abstract: The development and implementation of a new design methodology that will provide integrated product/process design/development through robust design simulation are described. The key elements of the methodology are a top down decision support system, systems engineering methods and tools, quality engineering methods and tools, and a computer integrated environment. The use of IPPD methodology in developing and evaluating metrics for the High Speed Civil Transport project is discussed as an example. Also discussed are examples for rotorcraft and other aircraft. (AIAA)
title = {Integrated product/process design/development (IPPD) through robust design simulation - The key for affordable systems},
Schrage, D.P. & Mavris, D.N. Integrated product/process design/development (IPPD) through robust design simulation - The key for affordable rotorcraft
Vol. 1AHS, Annual Forum, 51st, Fort Worth, TX, Proceedings; UNITED STATES; 9-11 May 1995, pp. 11-26 conference
Abstract: This paper describes the newly developed Georgia Tech Aerospace Systems Design Laboratory IPPD methodology and the way it is implemented. This methodology consists of four key elements: a top down decision support process, systems engineering methods and tools, quality engineering methods and tools, and a computer integrated environment. A detailed example is provided on how it is being utilized to assist NASA and the commercial transport industry in developing evaluating metrics for the high speed civil transport. Examples for rotorcraft and other aircraft are also discussed. The paper also provides arguments as to why, for all aerospace systems, and in particular rotorcraft, IPPD through robust design simulation is the key for affordable systems. (Author)
title = {Integrated product/process design/development (IPPD) through robust design simulation - The key for affordable rotorcraft},
Classification: 12 Spacecraft (MT); 66 SYSTEMS ANALYSIS (AH).
Schrage, D.P. & Mavris, D.N. Integrated design and manufacturing for the High Speed Civil Transport
1993 AIAA, Aircraft Design, Systems and Operations Meeting, Monterey, CA; UNITED STATES; 11-13 Aug. 1993 conference
Abstract: An account is given of the development status of an educational environment system for the integrated design/manufacturing, or 'concurrent engineering', of an HSCT. Attention is given to the quality function deployment (QFD) matrices. The second QFD matrix identifies the relationships between the key product and process characteristics of the first such matrix, as well as the criteria that could be used to generate a criterion function and feasibility constraints. (AIAA)
author = {Daniel P. Schrage and Dimitri N. Mavris},
title = {Integrated design and manufacturing for the High Speed Civil Transport},
booktitle = {AIAA, Aircraft Design, Systems and Operations Meeting, Monterey, CA; UNITED STATES; 11-13 Aug. 1993},
Conference: AIAA, Aircraft Design, Systems and Operations Meeting, Monterey, CA; UNITED STATES; 11-13 Aug. 1993.
Schrage, D.P., Mavris, D.N., Hale, M., Rohl, P., Abel, R. & Marx, W. Integrated Design and Manufacturing for the High Speed Civil Transport
Abstract: In June 1992, Georgia Tech's School of Aerospace Engineering was awarded a NASA University Space Research Association (USRA) Advanced Design Program (ADP) to address "Integrated Design and Manufacturing for the High Speed Civil Transport (HSCT)" in its graduate Aerospace Systems Design courses. This report summarizes the results of the five courses incorporated into the Georgia Tech's USRA ADP program. It covers AE8113: Introduction to Concurrent Engineering AE4360: Introduction to CAE/CAD, AE4353: Design for Life Cycle Cost, AE6351: Aerospace Systems Design I, AE6352: Aerospace Systems Design II. AE8113: Introduction to Concurrent Engineering was an introductory course addressing the basic principles of Concurrent Engineering (CE) or Integrated Product Development (IPD). The design of a total system was not the objective of this course. The goal was to understand and define the "up-front" customer requirements, their decomposition, and determine the value objectives for a complex product, such as the High Speed Civil Transport (HSCT). A generic CE Methodology developed at Georgia Tech was used for this purpose.
author = {Daniel P. Schrage and Dimitri N. Mavris and Mark Hale and Peter Rohl and Reginald Abel and William Marx},
Schrage, D.P., Mavris, D.N. & Wasikowski, M. GTPDP - A rotary wing aircraft preliminary design and performance estimation program including optimization and cost
1990 Vertical Lift Aircraft Design Conference, San Francisco, CA; UNITED STATES; 17-19 Jan. 1990, pp. 19 conference
Abstract: The Georgia Tech Preliminary Design and Performance Program (GTPDP) research objective is to develop a simple, rapid, and reliable analytical method for carrying out helicopter preliminary design and performance analysis for utilization in rotorcraft design courses and independent design assessments. Flight test data and predictions are compared for three rotorcraft (YAH-64, CH-3E and HH-53C) in different weight categories. The designed code is based on the original single rotor helicopter design and performance program codes. It is concluded that good correlations are achieved between predicted and measured results and that the developed code can be used to predict the behavior of a given helicopter with adequate accuracy. (R.E.P.)
author = {Daniel P. Schrage and Dimitri N. Mavris and Mark Wasikowski},
title = {GTPDP - A rotary wing aircraft preliminary design and performance estimation program including optimization and cost},
booktitle = {Vertical Lift Aircraft Design Conference, San Francisco, CA; UNITED STATES; 17-19 Jan. 1990},
Conference: Vertical Lift Aircraft Design Conference, San Francisco, CA; UNITED STATES; 17-19 Jan. 1990.
Schrage, D.P., Yillikci, Y.K., Phillips, J.W. & Mavris, D.N. Conceptual design and proposed development of the GAP-4 multi-purpose small utility helicopter
Abstract: This paper presents the GAP-4 helicopter's conceptual design and discusses a planned university/industry/government collaborative development program in both Turkey and the U.S. that will complete the design of the GAP-4 and demonstrate its capabilities for manufacture in Turkey. A major objective of this program will be to foster the development of a helicopter industry in the Republic of Turkey. (Author)
author = {Schrage, Daniel P and Yillikci, Y K and Phillips, Jerry W and Mavris, Dimitri N},
title = {Conceptual design and proposed development of the GAP-4 multi-purpose small utility helicopter},
Soban, D.S., Biltgen, P. & Mavris, D.N. A Technology Assessment Methods Survey: Concepts and Tools
Abstract: Complex system design in today's world is an increasingly difficult challenge. Dramatic leaps in system complexity, rapidly emergent technologies, and increased coupling of system dependencies serve to make traditional ad-hoc system design and analysis methods impractical and often ineffective. In addition, shrinking research and development budgets and limited resources are impacting system designers: they are being asked to do more with less. New tools and methods that provide structured, traceable, yet rapid, flexible, and computationally inexpensive design and analysis capabilities are needed. The paper presented here conducts a survey of such tools and methods that have been in development and use by the Aerospace Systems Design Laboratory (ASDL) at the Georgia Institute of Technology.
@conference{Soban2005,
author = {Soban, Danielle S and Biltgen, Patrick and Mavris, Dimitri N},
title = {A Technology Assessment Methods Survey: Concepts and Tools},
Soban, D.S. & Mavris, D.N. The need for a military system effectiveness framework - The system of systems approach
Abstract: The need for a comprehensive framework for the analysis of military system effectiveness is presented. Changes in the world's economy and its effect on decision making is discussed, as well as the three primary ways decision makers use information: resource allocation, requirements definition, and trade studies between system components. "System" and "system effectiveness" are clearly defined. The idea of a system of systems formulation for military system effectiveness analysis is presented, discussing the need to expand the consideration of the system from the vehicle (engineering) level to the theater or campaign level. The use of probability theory as part of the methodology is defended. Finally, an intuitive overview of the proposed methodology is presented, in a step by step manner. The methodology is called POSSEM (PrObabilistic System of Systems Effectiveness Methodology). (Author)
@inproceedings{Soban2001,
author = {Soban, Danielle S and Mavris, Dimitri N},
title = {The need for a military system effectiveness framework - The system of systems approach},
Soban, D.S. & Mavris, D.N. Methodology for assessing survivability tradeoffs in the preliminary design process
Abstract: A synthesis and modeling environment is formulated and presented that will allow trade-off studies and analysis of survivability concepts to be conducted. This environment then becomes the testbed used to develop a comprehensive and structured probabilistic methodology, called the Probabilistic System of System Effectiveness Methodology (POSSEM), that will allow these trades to be conducted. Initially, consideration of the survivability discipline will be restricted to components of aircraft susceptibility. The methodology is presented here in its formative state, with primary issues being identified and tentative solutions presented. A theater level test case of susceptibility trades is presented. (Author)
title = {Methodology for assessing survivability tradeoffs in the preliminary design process},
Stetner, M.M., N, D. & Schrage, D.P. A method for flexible design integration
1996 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 4; UNITED STATES; 15-17 Apr. 1996, pp. 1899-1907 conference
Abstract: A method is described which facilitates conversion of a design problem formulation into a solution strategy, as well as the generation of a tool for its execution. Identification of the problem structure is accomplished by stepwise reduction of the formulation's level of abstraction. A solution strategy is devised whose execution can be substantiated by problem-dependent grouping of contributing analyses determining how problem-independent tools are used. These two elements are used in an architecture for design environments which allows restructuring of the design process at run time. The implementation of such a framework is presented. Its application to a large-scale optimization problem using nonhierarchic decomposition for tiltrotor aircraft aeroservoelastic tailoring is discussed. Accommodation of multiple decomposition is required for future design environments. The presented architecture provides the required flexibility and could therefore serve as a prototype for the structure of such frameworks. (Author)
@conference{Stetner1996,
author = {Stetner, Martin Mavris, and Dimitri N and Schrage, Daniel P},
title = {A method for flexible design integration},
booktitle = {AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 4; UNITED STATES; 15-17 Apr. 1996},
Conference: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference and Exhibit, 37th, Salt Lake City, UT, Technical Papers. Pt. 4; UNITED STATES; 15-17 Apr. 1996.
Classification: 11 Aircraft (MT); 39 STRUCTURAL MECHANICS (AH).
Stettner, M.M., N, D. & Schrage, D.P. Aeroelastic tailoring of a civil tilt rotor configuration
1995 Vertical Lift Aircraft Design Conference, San Francisco, Proceedings; UNITED STATES; 18-20 Jan. 1995.2-1 to 4.2-14, pp. 4 conference
Abstract: Progress in establishing an analysis package and design /optimization framework for preliminary design of a civil tiltrotor aircraft is reported. Updates to the sizing/performance program VASCOMP and Equivalent LAminated Plate Solution, ELAPS, are described. Correlation of this updated ELAPS (now including shear panels) and a state-space unsteady aerodynamic analysis, PWAKE, with reference results from the Automated STRuctural Optimization System, ASTROS, is shown. A generic UNIX-based, flexible executive system for multidisciplinary design /optimization tasks is presented. The framework features a central data base, provisions for parallel analysis execution on different host computers connected to the same file server, local sensitivity calculation using finite differencing, global sensitivity calculation, and a utility allowing different levels of user control. (Author)
@conference{Stettner1995,
author = {Stettner, Martin Mavris, and Dimitri N and Schrage, Daniel P},
title = {Aeroelastic tailoring of a civil tilt rotor configuration},
booktitle = {Vertical Lift Aircraft Design Conference, San Francisco, Proceedings; UNITED STATES; 18-20 Jan. 1995.2-1 to 4.2-14},
publisher = {Moffett Field, CA: NASA Ames Reproduction Technology Branch},
Conference: Vertical Lift Aircraft Design Conference, San Francisco, Proceedings; UNITED STATES; 18-20 Jan. 1995.
Stults, I.C., Wilson, J.S.B., Morris, E., Sara & Leahu-Aluas, Ion; Mavris, D. The Conceptual Design of CELESTE: a Cost-Effective, Low-Noise, Efficient, SBJ Turbofan Engine
2005 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit; Tucson, AZ; USA; 10-13 July 2005, pp. 1-10 conference
Abstract: In response to a Request for Proposal (RFP) issued by the AIAA Airbreathing Propulsion Technical Committee, a team of undergraduate students at Georgia Institute of Technology proposed CELESTE, a cost-effective, low-noise, efficient, Supersonic Business Jet (SBJ) turbofan engine, which is capable of an entry into service of 2010, as mandated by the RFP. The RFP stipulated that the powerplant must meet several stringent criteria, including maximum noise levels during takeoff, a maximum tip diameter, and an ability to operate on a specified supersonic business jet airframe that meets certain performance requirements. The figures of merit for CELESTE are the thrust specific fuel consumption for the proposed powerplant, the maintenance and acquisition costs, and the weight of the engine and aircraft. In October 2004, the CELESTE design team at Georgia Institute of Technology was officially awarded first place in the AIAA Undergraduate Team Engine Design Competition.
@conference{Stults2005,
author = {Stults, Ian C and Wilson, J Scott Beisecker, and Elise Morris, and Sara and Leahu-Aluas, Ion; Mavris, Dimitri},
title = {The Conceptual Design of CELESTE: a Cost-Effective, Low-Noise, Efficient, SBJ Turbofan Engine},
booktitle = {41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit; Tucson, AZ; USA; 10-13 July 2005},
publisher = {American Institute of Aeronautics and Astronautics, The Aerospace Center, 370 L'Enfant Promenade, SW, Washington, DC, 20024, USA},
Conference: 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit; Tucson, AZ; USA; 10-13 July 2005.
Tai, J.C., Mavris, D.N. & Schrage, D.P. A comparative assessment of high-speed rotorcraft concepts (HSRC) - Reaction driven stopped rotor/wing and variable diameter tiltrotor
Abstract: The objective of this paper is to illustrate the methods and tools developed to size and synthesize a stopped rotor/wing vehicle using a reaction drive system, including how this design capability is incorporated into a sizing and synthesis tool, VASCOMP II. This new capability is used to design a vehicle capable of performing a V-22 escort mission, and a sized vehicle description with performance characteristics is presented. The resulting vehicle is then compared side-by-side to a variable diameter tiltrotor designed for the same mission. Results of this analysis indicate that the reaction-driven rotor concept holds promise relative to alternative concepts, but that the variable diameter tiltrotor has several inherent performance advantages. Additionally, the stopped rotor/wing needs considerably more development to reach maturity. (Author)
@conference{Tai1997,
author = {Tai, Jimmy C and Mavris, Dimitri N and Schrage, Daniel P},
title = {A comparative assessment of high-speed rotorcraft concepts (HSRC) - Reaction driven stopped rotor/wing and variable diameter tiltrotor},
Tai, J.C., Mavris, D.N. & Schrage, D.P. An assessment of a reaction driven stopped rotor/wing using circulation control in forward flight
Abstract: The most notable program which has addressed the technology challenges of accomplishing a high speed civil transport mission is the High Speed Rotorcraft Concept (HSRC) program. Among the long list of potential configurations to fulfill the HSRC intended mission, the stopped rotor/wing is the least investigated due to the fact that the existing rotorcraft synthesis codes cannot handle this type of vehicle. In order to develop such a tool, a designer must understand the physics behind this unique concept. The uniqueness of stopped rotor/wing vehicles that use reaction drive can be found in the tight coupling that is present between the rotor and the engine, which in turn requires these subsystems to be sized concurrently rather than in isolation. A methodology and simulation tool capable of handling this coupling is under development at the Aerospace Systems Design Laboratory at the Georgia Institute of Technology. The development of a new design tool (TJCC) and the use of a statistical technique called Response Surface Methodology, linked into the V/STOL Aircraft Sizing and Performance Computer Program (VASCOMP II), has provided the capability of sizing stopped rotor/wings. The forward flight regime for both the helicopter and fixed-wing modes of stopped rotor/wing configurations are discussed. Representative results presented include performance characteristics such as the horsepower-required curves versus forward flight for both the rotorcraft and fixed-wing modes of operation. The mass flow requirements and the transition performance associated with this aircraft are also examined. (AIAA)
title = {An assessment of a reaction driven stopped rotor/wing using circulation control in forward flight},
Tai, J.C., Mavris, D.N. & Schrage, D.P. Application of a response surface method to the design of tip jet driven stopped rotor/wing concepts
Abstract: A computer simulation code has been developed to size reaction driven stopped rotor/wing vehicles which may or may not enable Circulation Control. The difficulty in sizing such a concept is primarily due to the unique coupling of rotor and engine which need to be sized concurrently since they are directly linked to each other and cannot be studied in isolation. This coupling, in fact, is not seen in any other concept. The methodology and computer simulation tool presented in this paper show how this coupling is accomplished. The results from this rotor/engine coupling are presented in the form of response surface equations (RSEs) derived through the application of response surface methodology. These RSEs also provide the designer with a unique ability to predict what the response will be, based on the settings of the design variables that he/she chooses. The robustness advantages of using these RSEs in the vehicle sizing portion of the overall design methodology for the stopped rotor /wing configurations are also presented. (Author)
title = {Application of a response surface method to the design of tip jet driven stopped rotor/wing concepts},
Tai, J.C.M., McClure, E.K., Mavris, D.N. & Burg, C. Propulsion System Modeling and Simulation
2002 2nd JANNAF Modeling and Simulation Subcommittee Meeting; 01 Apr. 2002, pp. 49-58 conference
Abstract: The Aerospace Systems Design Laboratory at the School of Aerospace Engineering in Georgia Institute of Technology has developed a core competency that enables propulsion technology managers to make technology investment decisions substantiated by propulsion and airframe technology system studies. This method assists the designer/manager in selecting appropriate technology concepts while accounting for the presence of risk and uncertainty as well as interactions between disciplines. This capability is incorporated into a single design simulation system that is described in this paper. This propulsion system design environment is created with a commercially available software called iSIGHT, which is a generic computational framework, and with analysis programs for engine cycle, engine flowpath, mission, and economic analyses. iSIGHT is used to integrate these analysis tools within a single computer platform and facilitate information transfer amongst the various codes. The resulting modeling and simulation (M&S) environment in conjunction with the response surface method provides the designer/decision-maker an analytical means to examine the entire design space from either a subsystem and/or system perspective. The results of this paper will enable managers to analytically play what-if games to gain insight in to the benefits (and/or degradation) of changing engine cycle design parameters. Furthermore, the propulsion design space will be explored probabilistically to show the feasibility and viability of the propulsion system integrated with a vehicle.
author = {Tai, Jimmy C M and McClure, Erin K and Mavris, Dimitri N and Burg, Cecile},
title = {Propulsion System Modeling and Simulation},
booktitle = {2nd JANNAF Modeling and Simulation Subcommittee Meeting; 01 Apr. 2002},
Conference: 2nd JANNAF Modeling and Simulation Subcommittee Meeting; 01 Apr. 2002.
Other Numbers: RECON no.20020073817.
Notes: Volume 1, CPIA-Publ-715-Vol-1.
Classification: 37 MECHANICAL ENGINEERING (AH).
Talley, D.N. & Mavris, D.N. An Adaptive Environment for the Identification of Morphing UCAV Mission Requirements
Abstract: Over the past few years there has been a considerable amount of interest in morphing aircraft. Instead of focusing on morphing technology or even a specific aircraft configuration, this paper describes the process for the identification of the mission requirements for a morphing UCAV. An adaptive environment for evaluating the benefits of morphing aircraft from a system of systems perspective was created through the utilization of a program called Aircraft Time Critical Target Mission Analysis Simulation (ATMAS) in conjunction with meta-modeling techniques and data evaluation algorithms. ATMAS models a wartime search and destroy mission scenario for various existing and future aircraft fleets, and it was used to ascertain the benefits of a fleet of morphing UCAVs in comparison to alternative present and future operational architectures. This allowed for mission requirements to be determined and the concept of a morphing aircraft to be evaluated without limiting the design space by specifying individual aircraft performance criteria.
@conference{Talley2006,
author = {Talley, Diana N and Mavris, Dimitri N},
title = {An Adaptive Environment for the Identification of Morphing UCAV Mission Requirements},
Talley, D.N., Schellpfeffer, N.J., Carl & Mavris, D.N. Methodology for the Mission Requirement Determination and Conceptual Design of a Morphing UCAV
Abstract: There has been a growing trend towards designing aircraft capable of efficiently performing missions with widely disparate performance requirements. A solution for this is the development of morphing aircraft which are capable of dramatically changing both size and shape. Morphing to a certain extent has already been implemented on existing aircraft such as with Fowler flaps or variable sweep configurations. Advancements in smart materials and structures, however, have made the development of more drastic forms of morphing plausible. Two key questions which must be answered to design a morphing vehicle are: how to deduce the appropriate mission requirements, and how to design a morphing vehicle for those requirements. A critical aspect of the development of a morphing aircraft is determining the appropriate mission requirements for such an aircraft. The proposed method for determining these requirements is to develop a scenario based evaluation model which compares different operational fleet architectures, such as a fleet of morphing aircraft versus a fleet of multiple types of aircraft. This method creates a parametric environment to determine the most appropriate mission based upon a given set of objectives for all of the operational architectures. This allows a morphing fleet to be compared against other architectures to evaluate the potential benefit. After the mission requirements are determined the specific morphing vehicle can be designed. Initially, a baseline morphing concept (sliding skins, telescoping segments, swing wings, etc.) must be selected in order to provide for the size and shape change of the configuration. After the initial configuration concept has been determined the morphing geometric design process has two main steps. The first step is to parametrically vary the geometry for a given mission. From this analysis, a preliminary geometric shape is determined and then the mission is varied parametrically to determine the mission capability of that geometry. The ability of the vehicle is then compared to the requirements determined in the mission design phase and the process is iterated, at the geometric and/or mission requirements level as necessary to achieve an acceptable design.
author = {Talley, Diana N and Schellpfeffer, Nicolas Johnson, and Carl and Mavris, Dimitri N},
title = {Methodology for the Mission Requirement Determination and Conceptual Design of a Morphing UCAV},
Tejtel, D.M., N, D. & Hale, M. Conceptual aircraft design environment - Case study evaluation of computing architecture technologies
1998 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO, Collection of Technical Papers. Pt. 1; UNITED STATES; 2-4 Sept. 1998, pp. 81-89 conference
Abstract: Using a computational architecture, a procedure has been set up which allows a complete aerodynamic analysis of a High Speed Civil Transport. The computer architecture serves as a framework within which any number of diverse codes can be linked; data can be exchanged, stored, and otherwise managed, and decisions regarding the design of a vehicle can be made. The use of a computational tool called a Process Element as the method of code implementation allows the basic analysis procedure to be easily modified and added to and to be used with higher-level, probabilistic-based design methods. By means of the High Speed Civil Transport aerodynamic analysis example problem described in this paper, the key features of the computational architecture, as well as its capabilities and limitations, are examined and evaluated. (Author)
@conference{Tejtel1998,
author = {Tejtel, Daniel Mavris, and Dimitri N and Hale, Mark},
title = {Conceptual aircraft design environment - Case study evaluation of computing architecture technologies},
Thomas, V.K. & Mavris, D.N. Non-Optimal Configuration Selection During Conceptual Design
Abstract: It is often assumed that engineers and designers optimize their designs for a specific set of metrics, such as performance or cost. However, as engineering designers are humans and human decision makers do not necessarily optimize every decision, this is not always the case. This paper will address a set of human decision making activities in an early conceptual design phase of an engineering project: configuration selection. It will examine how the human decision makers actually make decisions, in context, during this phase of design, using the tools and choices that are available to them. It will examine the cognitive aspects of decision making and attempt to explain why conceptual design phase engineering decisions may appear less than fully rational and result in a non-optimal configuration. It will examine what aspects of intuition, fallacies and heuristics, biases, and risk management strategies play a role in conceptual design configuration selection. The perceived pressures that individual decision makers face when working within a corporation are examined from the perspective of how these pressures influence decisions and decision justification. Lastly, it will attempt to explain why different sets of people, who have the same set of performance requirements, can each choose different, non-optimal, system designs.
@conference{Thomas2006,
author = {Thomas, Victoria K and Mavris, Dimitri N},
title = {Non-Optimal Configuration Selection During Conceptual Design},
Utturwar, A., Rallabhandi, S., DeLaurentis, D. & Mavris, D. A bi-level optimization approach for technology selection (for aircraft design)
Abstract: Technology selection is a crucial step in the process of aircraft design. If the performance and economic requirements are not fulfilled for any combination of the design variables, new technologies need to be infused in the design. Typically, the designer has a pool of technology options. The technologies to be infused in the new design are to be selected from this pool so as to achieve improvements such as increased performance, reduced risk, reduced cost etc. Thus, it is critical to be able to perform a quick and accurate assessment of the available technologies in the early stages of the design process. However, if the set of available technologies is large, the designer runs into a huge combinatorial optimization problem. To tackle the technology selection problem, a systematic approach called Technology Identification, Evaluation and Selection (TIES) has been developed to choose the best set of technologies and arrive at a feasible and viable design solution. However, the issue of dealing with large combinatorial problems still remains. A new approach for tackling the same problem of technology selection was inspired from the TIES methodology and is discussed in this paper. This approach is based on identifying an optimal point in an intermediate variable space, which later on serves as the target point for technology selection. The new approach, called the 'bi-level approach' provides additional insights and expedites technology selection, thus rendering efficiency to the preliminary design process. The bi-level approach is described, and its application to an aircraft design problem is presented. (Author)
@inproceedings{Utturwar2002,
author = {Utturwar, Aditya and Rallabhandi, Sriram and DeLaurentis, Daniel and Mavris, Dimitri},
title = {A bi-level optimization approach for technology selection (for aircraft design)},
Villeneuve, F. & Mavris, D.N. A New Method of Architecture Selection for Launch Vehicles
2005 AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies; Capua; Italy; 16-20 May 2005, pp. 1-17 conference
Abstract: During the early stages of conceptual design, decisions regarding the vehicle and system configurations will have the most impact on the program cost and vehicle performance. For a launch vehicle, this phase consists of selecting the vehicle and system architectures. Since there are several complex systems forming such a vehicle, selecting the best configuration becomes a very difficult task. Traditionally, this phase is performed by disciplinary experts who select the architecture based on engineering intuition and personal preferences. However, because of the high level of complexity and interdependency between the systems of the vehicle, this approach is very inefficient. In order to address this concern, a Rapid Access-to-Space Analysis Code (RASAC) has been developed at the Aerospace Systems Design Lab at the Georgia Institute of Technology. The goal of this tool is to enable comparisons of launch vehicle architectures in a quick and accurate fashion. This paper will describe the underlying models of RASAC as well as an example of launch vehicle configuration selection. The benefits of this new approach will also be illustrated.
@conference{Villeneuve2005,
author = {Villeneuve, Frederic and Mavris, Dimitri N},
title = {A New Method of Architecture Selection for Launch Vehicles},
booktitle = {AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies; Capua; Italy; 16-20 May 2005},
Conference: AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies; Capua; Italy; 16-20 May 2005.
Villeneuve, F.M., Dimitri & Waters, M. Probabilistic analysis of turbine-based combined cycle space vehicles
2004 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit; Fort Lauderdale, FL; July 11-14. conference
Abstract: Current methodology for the conceptual design of space vehicles requires the evaluation of a large number of different concepts and configurations early during the design process. With existing legacy codes, evaluating the mission-related and economic performance of all design combinations becomes prohibitively time consuming and design space limiting. To address these issues, a physics-based modeling approach has been developed. This code, named Rapid Access-to-Space Analysis Code, can model multi-stage space vehicles with rocket and/or airbreathing propulsion. Its sizing and synthesis procedure as well as its models are presented in this paper. Using RASAC, a probabilistic requirements exploration environment has been created for two-stage-to-orbit vehicle designs using a turbine-based combined cycle propulsion system.
author = {Villeneuve, Frederic Mavris, and Dimitri and Waters, Mark},
title = {Probabilistic analysis of turbine-based combined cycle space vehicles},
booktitle = {40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit; Fort Lauderdale, FL; July 11-14.},
Conference: 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit; Fort Lauderdale, FL; July 11-14, 2004.
Classification: 18 Spacecraft Design, Testing and Performance (AH).
Villeneuve, F.O., Jan & Mavris, D. Probabilistic conceptual design analysis of multi-stage launch vehicles
Abstract: Current methodology for the conceptual design of launch vehicles necessitates the evaluation of a large number of different concepts and configurations. With existing legacy codes, evaluating the performance of all design combinations becomes very time-consuming and design space limiting. Up to now, a commonly used solution to this problem has been the creation of quadratic response surface equations. However, some key design metrics of multi-stages space vehicles exhibit highly non-linear responses and cannot be adequately modeled by such response surface equations. To address this issue, a new Rapid Access-to- Space Analysis Code (RASAC) and Requirements Exploration Tool (RET) have been created and are described in this paper. Case study examples are shown in order to see the design process improvement.
@conference{Villeneuve2004a,
author = {Villeneuve, Frederic Osburg, and Jan and Mavris, Dimitri},
title = {Probabilistic conceptual design analysis of multi-stage launch vehicles},
Volovoi, V.Z., Jack & Mavris, D. Assessment of the efficiency of partitioned response surface equations in structural applications
2003 44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Norfolk, VA; USA; 7-10 Apr. 2003 conference
Abstract: The relative merits of various methods of meta-modeling for large numbers of independent variables are assessed and compared. Several benchmark problems based on thermal and structural finite element models are considered. Such fully parametric models are constructed to be simple enough to facilitate fast multiple runs, yet complex enough to reflect some salient features of much larger models that are used in real-life applications. In particular, zoning of independent variables is considered: the model is divided into several zones, so that input variables (e.g., external temperature or wall thickness) can be varied independently for each zone. Such problems naturally may lead to consideration of partitioned meta-models: therein, the independent variables can be grouped either in accordance with the location (zone) or in accordance with the type of variable. Particular attention is paid to the question of coupling between the groups. The relative efficiency and accuracy of the resulting partitioned designs of experiments is compared to traditional meta-modeling techniques. It is shown that an optimal choice of a meta-model might depend on the type of the modeled response (e.g., whether the response is local or global and whether it is cumulative or extreme).
@conference{Volovoi2003,
author = {Volovoi, Vitali Zentner, and Jack and Mavris, Dimitri},
title = {Assessment of the efficiency of partitioned response surface equations in structural applications},
booktitle = {44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Norfolk, VA; USA; 7-10 Apr. 2003},
Conference: 44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference; Norfolk, VA; USA; 7-10 Apr. 2003.
Wallace, J., Volovoi, V. & Mavris, D. A method for modeling system driven uncertainty during probabilistic part life analyses
Abstract: Probabilistic part life analyses of turbine components have typically been conducted in an ad-hoc fashion with respect to the influence of the system. While this approach greatly simplifies the analysis, significant errors and misleading results are possible. However, directly modeling the system analyses in a fully probabilistic and integrated fashion can be prohibitive in terms of the infrastructure required. An efficient approach to characterizing and quantifying the system-driven input for probabilistic part life assessments is proposed. The approach is demonstrated for a turbine blade operating in a medium size commercial transport jet. The results of this demonstration illustrate how the component parameters and failure mechanisms can be qualitatively identified and the complex probabilistic input modeled as driven by the system behavior.
@conference{Wallace2004,
author = {Wallace, Jon and Volovoi, Vitali and Mavris, Dimitri},
title = {A method for modeling system driven uncertainty during probabilistic part life analyses},
Wallace, J.M. & Mavris, D.N. Creep life uncertainty assessment of a gas turbine airfoil
Abstract: Hot gas path turbine components are exposed to very severe and complex boundary conditions and many other sources of variation during their design, production, and operation. Consequently, the useful life of these components can exhibit considerable scatter. A complex, multi-physics environment has been created to automate the bulk creep life assessment of a gas turbine airfoil for a land-based, heavy duty power generation unit. An uncertainty assessment using the combined response surface Monte Carlo method is conducted with the developed environment. Results of this study are given and found to be in agreement with a more theoretical solution using power series approximation. Some widely used assumptions in conducting component level reliability assessments are investigated and discussed.
author = {Wallace, Jon M and Mavris, Dimitri N},
title = {Creep life uncertainty assessment of a gas turbine airfoil},
Wallace, J.M. & Mavris, D.N. Propulsion system reliability prediction and optimization using a multiphysics environment
Abstract: A multiphysics-based reliability assessment of a nominal aircraft propulsion system is demonstrated using the Response Surface/Monte Carlo approach and Fault Tree Analysis. The failure assessment of a first stage turbine rotor airfoil, consisting of overstress, fatigue, and creep with respect to operational, material, and geometric parameters, is performed using a first-order integrated cycle-thermomechanical-failure environment. The failure condition of the airfoil is modeled as a series or 'weakest link' system of independent failure events. Fault Tree Analysis is combined with Monte Carlo Simulation to determine the airfoil series system reliability. The response surface method approach is applied to generate a metamodel of reliability, a probabilistic quantity. The utility of such an approach for enhancing propulsion system design considerations is demonstrated. (Author)
@inproceedings{Wallace2002,
title = {Propulsion system reliability prediction and optimization using a multiphysics environment},
Won, H., Levine, S., Pfaender, J.H. & Mavris, D.N. Using response surface metamodels to optimize the aerodynamic performance of a high-speed standoff missile within a multi-disciplinary environment
Abstract: This report summarizes the feasibility of implementing a response surface metamodel (RSM) in a high-speed standoff missile (HSSM) multi-disciplinary mission analysis. The RSM, which is a model of an exact analysis, is used to optimize the missile aerodynamic performance for any given mission. Each mission is defined as a function of the mission parameters. The optimization schemes use flight condition information and missile requirements from the upstream mission analysis, and find the optimum missile geometry parameters for that mission. The geometry parameters are then returned to the system analysis to complete the mission evaluation under optimal aerodynamic performance. The optimization scheme allows the variation of the missile geometry without increasing the number of runs in a parametric design study, such as a Design of Experiments (DOE). Results are achieved for two modules, namely the fuselage aerodynamics and the tail fin aerodynamics. RSM optimization schemes were created and implemented into the modules. The transformed modules were tested to observe the behavior and accuracy of the schemes. Comparison is made between the optimal geometries found with and without the use of the RSM. The comparison shows that the RSM optimization returns similar results, and does so in a significantly shorter amount of time. In addition, the aerodynamic design spaces are analyzed in conjunction with the optimization behavior to predict possible mishaps in the optimization process. The use of the RSM is shown to alleviate problems such as multi-modal design spaces. (Author)
@inproceedings{Won2002,
author = {Won, Henry and Levine, Simon and Pfaender, Jens Holger and Mavris, Dimitri N},
title = {Using response surface metamodels to optimize the aerodynamic performance of a high-speed standoff missile within a multi-disciplinary environment},
Zentner, J., Volovoi, V. & Mavris, D. Preliminary evaluation of a hierarchical metamodeling technique for systems with a large number of parameters
Abstract: This paper is a continuation of research aimed at reducing the amount of computational expense required to generate metamodels of large scale computer simulations. Large scale in this context refers to systems involving many input parameters. There are essentially two separate groups of methods that have been developed or adopted for these large scale systems. In both cases, the ultimate goal of the methods is to create accurate metamodels of the sys- tem while at the same time requiring significantly less data to be collected as compared to standard design and analysis of computer experiments techniques. These two groups of techniques are distinguished by their treatment of the input parameters. One group takes an all-at-once approach by analyzing the effects of all input parameters at the same time and then applies some form of stepwise regression to create a reduced model of the system. The other group of techniques first partitions the input parameters into disjoint subgroups, analyzes each group independently and then recombines the sub- group data to create the final metamodel. Of the partitioning techniques there are two general categories, hierarchical and non-hierarchical. This paper further expands upon two hierarchical metamodeling methods, namely the General Composite Function method and the Lumped Parameter method. For each of these large scale methods, the basic steps for their implementation are outlined in conjunction with caveats for applying them. As the Lumped Parameter method constitutes a new body of work, preliminary results for its implementation are also investigated. The paper concludes with a summary of future work aimed at improving the accuracy of the Lumped Parameter method.
@conference{Zentner2004,
author = {Zentner, Jack and Volovoi, Vitali and Mavris, Dimitri},
title = {Preliminary evaluation of a hierarchical metamodeling technique for systems with a large number of parameters},
Zentner, J., Volovoli, V. & Mavris, D. Overview of metamodeling techniques for problems with a large number of input parameters
Abstract: It is common practice for systems engineers to develop simplified models to approximate and replace more complex design tools. By doing so, overall analysis time can be reduced, giving the designer the ability to perform a more thorough design space exploration. In order to generate surrogate models, a certain amount of information is needed from the system in question. Specifically, the designer needs enough data points from within the design space to be able to create a metamodel of that space. The number of design variables being investigated determines the number of dimensions of the design space, which directly affects the amount of data required to accurately fit a model to that n-dimensional space. As a result, typical metamodeling methods are generally limited to analyses involving on the order of 10 to 15 factors. Several techniques have recently been developed to address this shortcoming, thereby allowing the designer to perform design tradeoffs involving a large number of design factors. These techniques include partitioned response surfaces, hierarchical and non-hierarchical metamodels, and various all-at-once approaches such as supersaturated Design of Experiments.
author = {Zentner, Jack and Volovoli, Vitali and Mavris, Dimitri},
title = {Overview of metamodeling techniques for problems with a large number of input parameters},
Zhang, H.P., R, J.V. & Mavris, D.N. Ship airwake effects on the helicopter rotor aerodynamic loads
1994 AIAA Atmospheric Flight Mechanics Conference, Scottsdale, AZ, Technical Papers; UNITED STATES; 1-3 Aug. 1994, pp. 419-424 conference
Abstract: A previously developed approach to modeling and simulation of ship airwake has been used in the study of airwake effects on rotor aerodynamic loads of a four-bladed articulated rotor system. Using full scale at sea test data, the current study identifies a power spectral model for the vertical component of the ship airwake velocity. Also, a spline-fit model is developed for the mean airwake velocities around the ship deck. Using simulated samples of vertical airwake velocities and a simplified rotor aerodynamic model, effects of airwake velocities on rotor rolling and pitching moments and rotor thrust are investigated. (Author)
@conference{Zhang1994,
author = {Zhang, Hong Prasad, and J V R and Mavris, Dimitri N},
title = {Ship airwake effects on the helicopter rotor aerodynamic loads},
booktitle = {AIAA Atmospheric Flight Mechanics Conference, Scottsdale, AZ, Technical Papers; UNITED STATES; 1-3 Aug. 1994},
Conference: AIAA Atmospheric Flight Mechanics Conference, Scottsdale, AZ, Technical Papers; UNITED STATES; 1-3 Aug. 1994.
Notes: Technical Papers (A94-30422 10-08).
Zhao, Wei Hale, M., A, Craig, J.I. & Mavris, D.N. Findings on the CGI approach to enabling resources on the Internet (Common Gateway Interface)
2000 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 8th, Long Beach, CA; UNITED STATES; 6-8 Sept. 2000 inproceedings
Abstract: In collaborative design, the ability to exchange information among resources (e.g., people, databases, programs, etc.) is essential. The Internet provides a powerful and attractive mechanism to link such resources in a geographically distributed setting. A study summarized in this paper utilizes an accessible web framework and indicates that a popular resource integration technique using Common Gateway Interface (CGI) scripts on web servers provides a bottleneck when these resources are automated. This raises concerns about scalability and suggests caution in following this avenue for future engineering system designs. In particular, problems with data persistence and exchange in integrated systems are identified. A lean-server technique, by which an Internet server is embedded directly into the engineering system, is shown as one possible solution to the persistence problem. The added benefits of resource coupling and data flow enhancements using content-based markup languages, such as XML, are also explored. (Author)
@inproceedings{Zhao2000,
author = {Zhao, Wei Hale, Mark and A and Craig, James I and Mavris, Dimitri N},
title = {Findings on the CGI approach to enabling resources on the Internet (Common Gateway Interface)},
Classification: 82 DOCUMENTATION AND INFORMATION SCIENCE (AH).
Zhao, Yongjun Volovoi, V., V., Waters, M. & Mavris, D.N. Power plant systems operational scheduling using a dual-time scale
Abstract: One of the most challenging problems in the electric power generation business is balancing short term productivity with the optimal level of production over a long time period. In this paper a systematic approach to the modeling of gas turbine power plants for long term generation scheduling is introduced. For this purpose a dual time scale method is developed and demonstrated. This dual-scale approach combines the detailed granularity of the day-to-day operations with global (seasonal) trends, while keeping the resulting optimization model relatively compact. The results show that this approach can incorporate gas turbine performance, dynamic electric power markets, long term power plant generation scheduling, and preventive maintenance planning.
@conference{Zhao2004,
author = {Zhao, Yongjun Volovoi, Vitali and V. and Waters, Mark and Mavris, Dimitri N.},
title = {Power plant systems operational scheduling using a dual-time scale},
Zink, P.S.R., E, D. & Mavris, D.N. An integrated trim and structural design process for active aeroelastic wing technology
Abstract: A new method for concurrent trim and structural optimization of Active Aeroelastic Wing technology is presented. The new process treats trim optimization and structural optimization as an integrated problem in the same mathematical formulation, in which control surface gear ratios are included as design variables in a standard structural optimization algorithm. This new approach is in contrast to most of the existing AAW design processes in which structural optimization and trim optimization have separate objectives and are performed in an iterative sequential manner. The new integrated AAW design process is demonstrated on a lightweight fighter-type aircraft and compared to a sequential AAW design process. For this demonstration, the integrated process converges to a lower weight, and offers an advantage over the sequential process in that optimization is performed in one continuous run, whereas the sequential approach requires pausing and restarting the structural optimization to enable trim optimization. (Author)
@inproceedings{Zink2001a,
author = {Zink, P Scott Raveh, and Daniella E and Mavris, Dimitri N},
title = {An integrated trim and structural design process for active aeroelastic wing technology},
Zink, P., Raveh, D. & Mavris, D. Integrated trim and structural design process for active aeroelastic wing technology.
2003 Journal of Aircraft. May-June 2003
Abstract: A new method for concurrent trim and structural optimization of active aeroelastic wing technology is presented. The new process treats trim optimization and structural optimization as an integrated problem in which control surface gear ratios and structural design variables are posed together in the same optimization problem and act toward the same objective of weight minimization. This new design philosophy is in contrast to most existing active aeroelastic wing design processes in which structural optimization and trim optimization, each having their own different objectives and constraints, are performed in an iterative, sequential manner. The new integrated active aeroelastic wing design process is demonstrated on a lightweight fighter-type aircraft and compared to a more traditional, sequential active aeroelastic wing design process. For this demonstration, the integrated process converges to a lower weight and offers an advantage over the sequential process in that optimization is performed in one continuous run, whereas the sequential approach requires pausing and restarting the structural optimization to allow for trim optimization.
@article{Zink2003,
author = {Zink, P.S. and Raveh, D.E. and Mavris, D.N.},
title = {Integrated trim and structural design process for active aeroelastic wing technology.},
journal = {Journal of Aircraft. May-June 2003},
Zink, P.S., Mavris, D.N., Flick, P.M. & Love, M.H. Development of wing structural weight equation for active aeroelastic wing technology
Abstract: A multidisciplinary design study considering the impact of Active Aeroelastic Wing (AAW) technology on the structural wing weight of a lightweight fighter concept is presented. The study incorporates multidisciplinary design optimization (MDO) and response surface methods to characterize wing weight as a function of wing geometry. The study involves the sizing of the wing box skins of several fighter configurations to minimum weight subject to static aeroelastic requirements. In addition, the MDO problem makes use of a new capability, trim optimization for redundant control surfaces, to accurately model AAW technology. The response surface methodology incorporates design of experiments and least squares regression, and makes use of the parametric definition of a structural finite element model and an aerodynamic model to build response surface equations of wing weight as a function of wing geometric parameters for both AAW technology and conventional control technology. The goal for this design study is to demonstrate a process by which some of the benefits associated with AAW technology can be quantified over the wing geometry design space, so that future conceptual designers may make the best use of the technology. (Author)
@conference{Zink1999,
author = {Zink, P S and Mavris, Dimitri N and Flick, Peter M and Love, Michael H},
title = {Development of wing structural weight equation for active aeroelastic wing technology},
Zink, P.S., Mavris, D.N., Love, M.H. & Karpel, M. Robust design for aeroelastically tailored/active aeroelastic wing
1998 AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 7th, St. Louis, MO, Collection of Technical Papers. Pt. 1; UNITED STATES; 2-4 Sept. 1998, pp. 559-569 conference
Abstract: A study of multidisciplinary design concerning the incorporation of aeroelastic tailoring, control surface blending, and active aeroelastic wing concepts is presented. The design process incorporates response surfaces, fast probability integration, and modal-basis multidisciplinary design optimization to characterize the design space. The wing box skins of a representative fighter configuration with multiple wing control surfaces are sized to minimum weight. A design of experiments approach is developed for the gear ratios in control surface blending. Design optimization is conducted for each set of gearing functions. The control surface gear ratios are then treated as 'noise' in the structural design process, and a robust structural design is sought to account for the change in control laws that historically occur during the aircraft design process. The motivation for this methodology investigation is derived from the common occurrence of control law changes throughout the lifetime of an aircraft. (Author)
author = {Zink, P S and Mavris, Dimitri N and Love, Michael H and Karpel, Mordechay},
title = {Robust design for aeroelastically tailored/active aeroelastic wing},
Other Numbers: A98-39701 10-31; Contract: NAG1-1793; NGT-152156.
Zink, P.S., Mavris, D.N. & Raveh, D.E. Maneuver trim optimization techniques for active aeroelastic wings.
Vol. 38(6), pp. 1139-1146 article
Abstract: A method for performing trim optimization of active aeroelastic wing (AAW) technology, based on posing the trim problem as a linear programming problem and solving it with the simplex method, is presented. Trim optimization is then integrated with the structural design process in a sequential manner, such that new optimal deflections of the control surfaces are computed for every structural design iteration. The use of the simplex method for trim optimization allowed the elimination of nonphysical constraints that had to be imposed when a gradient-based method was used. This resulted in significantly better objectives for the trim optimization. The sequential AAW design process was demonstrated on a lightweight fighter-type aircraft performing symmetric and antisymmetric maneuvers at subsonic and supersonic speeds. The concurrent trim and structural optimization resulted in a significantly lighter structure compared to a structure designed with conventional control technology and to a structure employing AAW technology with fixed control-surface deflections. (Author)
author = {Zink, P S and Mavris, D N and Raveh, D E},
title = {Maneuver trim optimization techniques for active aeroelastic wings.},
Illustrations: Numerical Data.
Zink, P.S., Mavris, D.N. & Raveh, D.E. Integrated structural/trim optimization for active aeroelastic wing technology
Abstract: A new process for concurrent trim and structural optimization of Active Aeroelastic Wing (AAW) technology is presented. The new process treats trim optimization and structural optimization as integrated problems in the same mathematical formulation, in which control surface gear ratios are added as design variables to a standard structural optimization algorithm. This new approach is in contrast to most of the existing AAW design processes in which structural optimization and trim optimization are performed in an iterative, sequential manner. The new integrated AAW design process is demonstrated on a lightweight fighter type aircraft and compared to a sequential AAW design process. For this demonstration, the integrated process converges to a lower weight and offers an advantage over the sequential process in that optimization is performed in one continuous run, whereas the sequential approach requires pausing and restarting the structural optimization to allow for trim optimization. (Author)
author = {Zink, P S and Mavris, Dimitri N and Raveh, Daniella E},
title = {Integrated structural/trim optimization for active aeroelastic wing technology},
Zink, P.S., Mavris, D.N. & Raveh, D.E. Maneuver trim optimization techniques for Active Aeroelastic Wings
Abstract: A new method for performing trim optimization of Active Aeroelastic Wing (AAW) technology is presented. The method is based on posing the trim problem as a linear program and solving it with the simplex method. Trim optimization is then integrated with the structural design process in a sequential manner, such that new optimal deflections of the control surfaces are computed for every structural design iteration. The use of the simplex method for trim optimization allowed the elimination of non-physical constraints that had to be imposed when a gradient-based method was used. This resulted in significantly better objectives for the trim optimization. The sequential AAW design process was demonstrated on a lightweight fighter type aircraft performing symmetric and antisymmetric maneuvers at subsonic and supersonic speeds. The concurrent trim and structural optimization resulted in a significantly lighter structure compared to a structure designed with conventional control technology and to a structure employing AAW technology with fixed control surface deflections. (Author)
@conference{Zink2000a,
title = {Maneuver trim optimization techniques for Active Aeroelastic Wings},
Zink, P.S., Raveh, D.E. & Mavris, D.N. Robust structural design for Active Aeroelastic Wing with aerodynamic uncertainties
Abstract: A multidisciplinary design study for Active Aeroelastic Wing technology considering the uncertainty in maneuver loads estimated by linear aerodynamic theory is presented. The study makes use of a design of experiments/response surface methodology and modal-based structural optimization to construct deterministic relationships between wing structural weight and control laws design based on linear aerodynamics. CFD Navier-Stokes analysis is then used to define typical differences between rigid aerodynamic loads as predicted by nonlinear and linear theory. These differences are then used to define aerodynamic uncertainties in a probabilistic manner, which are propagated, through Latin Hypercube Sampling and modal-based static aeroelastic analysis, to a response function that represents the magnitude of structural redesign. Structural designs then are sought that are both low weight and whose performance is relatively invariant in the presence of load uncertainty. The motivation for this study is derived by the frequent inability to accurately represent maneuver loads on an aircraft structure, which often requires redesign (sometimes major) late in the design process as loads predictions become more accurate. (Author)
@conference{Zink2000b,
author = {Zink, P S and Raveh, Daniella E and Mavris, Dimitri N},
title = {Robust structural design for Active Aeroelastic Wing with aerodynamic uncertainties},
Zink, P.S.R., E., D. & Mavris, D.N. Robust structural design of an active aeroelastic wing with maneuver load inaccuracies
2004 Journal of Aircraft
Abstract: A multidisciplinary design methodology for aircraft structures subject to inaccuracies in aerodynamic load predictions is presented. A statistical load-correction model is developed that is based on typical differences between loads as predicted by nonlinear and linear aerodynamic theories. Load corrections are propagated to a response function that represents the magnitude of structural redesign that would be necessary when the structure is subject to variation in the loads to which it was designed. The method is applied to an active aeroelastic wing concept, in which both the structural and control law designs are highly sensitive to variations in the aerodynamic loads. Computational fluid dynamics Euler analysis is used to construct the load-correction model. The most critical loading condition is then identified and used to redesign the structure and control-surface gear ratios. The redesigned structure was found to be 11 percent heavier and significantly more robust than the structure that was optimized with the linear loads only. The present methodology provides a way to account for load inaccuracies in the early phases of the design process, thereby, reducing the need for redesign late in the design process as load predictions become more accurate.
author = {Zink, P. Scott Raveh, and Daniella E. and Mavris, Dimitri N.},
title = {Robust structural design of an active aeroelastic wing with maneuver load inaccuracies},
journal = {Journal of Aircraft},
Zink, P.S.R., E, D. & Mavris, D.N. Robust structural design of an active aeroelastic wing with maneuver load uncertainty
Abstract: A multidisciplinary design methodology for aircraft structures subject to uncertainty in aerodynamic load predictions is presented. A statistical load uncertainty model is developed that is based on typical differences between rigid aerodynamic loads as predicted by nonlinear and linear aerodynamic theories. Load uncertainties are propagated to a response function that represents the magnitude of structural redesign that would be necessary when the structure is subject to variation in the loads to which it was designed. The method is applied to an Active Aeroelastic Wing concept, in which both the structural and control law designs are highly sensitive to uncertainties in the aerodynamic loads. CFD Euler analysis is used to evaluate the nonlinear rigid loads due to a unit deflection of each trim parameter, from which the load uncertainty model is constructed. The most critical loading condition is then identified and used to redesign the structure and control surface gear ratios. The redesigned structure was found to be 11 percent heavier and significantly more robust than the structure that was optimized with the linear loads only. The motivation for this study is derived by the frequent inability to accurately represent maneuver loads on an aircraft structure early in the design process, which often requires redesign late in the design process as load predictions become more accurate. The present methodology can alleviate this problem by providing a way to account for load uncertainties in the early phases of the design process. (Author)
@inproceedings{Zink2002,
author = {Zink, Paul Scott Raveh, and Daniella E and Mavris, Dimitri N},
title = {Robust structural design of an active aeroelastic wing with maneuver load uncertainty},
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