  A crucial challenge in engineering modern, integrated systems is to produce
robust designs. Ensuring robust design is difficult because subsystem couplings
produce unpredictable response to changes in whole system specifications. Here,
we show that the response of design elements to whole-system specification
changes can be characterized, as materials are, using strong/weak and
brittle/ductile dichotomies. We find these dichotomies emerge from a mesoscale
treatment of early stage design problems that we cast in terms of stress-strain
relationships. Compared with other state-of-the-art techniques, we propose a
two-factor robustness metric that is computable for sets of design solutions.
We illustrate the use of this approach with examples of arrangement problems
drawn from naval engineering, however our approach is immediately applicable to
a broad range of problems in integrated systems design.
