He would, however, like to see models that could predict mold flows even more accurately, which could eliminate some prototyping stages. “If we could avoid that, it would help us get our products to the market faster,” he says.
Another thing that today’s modeling programs can’t do is predict how the composite materials will perform over time, such as after being installed in a vehicle for 150,000 or 200,000 miles. “We are talking about material compatibility, about heat and how the molecules are changing and how the performance and the crystals of the resin are changing; it’s very complex,” says Ved. For example, models that could predict that the material would not degrade any more than a certain tensile strength loss or elongation loss over time would save the automotive industry time and money.
When the aerospace industry was developing the Boeing 787 and the Airbus A350 a dozen years ago, the Federal Aviation Administration (FAA) was concerned that the composite materials being proposed for the new planes would not offer the safety of metallic structures. “So they were going to require [the manufacturers] to come back to scale testing of this new science, something that is almost impossible to do with big aircraft,” says Gerado Olivares, senior research scientist and director of computational mechanics and crash dynamics laboratories at Wichita State University’s National Institute for Aviation Research (NIAR).
NIAR has been working with the FAA since that time to develop techniques that will allow aerospace manufacturers to minimize full-scale testing for some applications, including the dynamic seat certification of both composite and metallic aircraft seats. “It has taken time to develop the metrics, and we are now working with the industry to implement all of these methodologies that we have developed,” says Olivares. “We have asked to use simulation to support the certification process, so that instead of having to run a full aircraft, you can just run a small section of the aircraft for the testing to validate the models.”
Using simulation programs, NIAR researchers have also gained a better understanding of the effect of bird strikes on the composite structures on aircraft exteriors. In the past, all of this work on dynamic impact was done by physical testing. But with these physical tests, researchers had trouble determining exactly what had happened during a failure, since they had only high-speed video or measurements from strength gauges to review. “You never know the sequence of the failure or the dynamic loads going through the structure at the time of the impact, because you don’t have any source of measuring that. So one thing that we’ve been able to do now with simulation is really quantify what all those loading conditions are,” says Olivares.