Methods for Robust Multidisciplinary Design

Robust design has been gaining wide attention and its applications have been extended to making reliable decisions when designing complex engineering systems under a multidisciplinary design environment. Though the usefulness of robust multidisciplinary design is widely acknowledged, its implementation is rare. 1 One of the reasons is due to the complexity and computational burden associated with the evaluation of performance variations caused by the randomness (uncertainty) of a system. In this paper, we develop a robust multidisciplinary design procedure that utilizes efficient methods for uncertainty analysis. Different from the existing uncertainty analysis techniques, our proposed techniques bring the features of MDO framework into consideration. The system uncertainty analysis method (SUAM) and the concurrent subsystem uncertainty analysis method (CSSUAM) are developed to estimate the mean and variance of system performance subject to uncertainties associated with both design parameters and design models. The techniques used for uncertainty analysis will significantly reduce the amount of design evaluations at the system level, and therefore improve the efficiency of robust design in the domain of MDO. The merits and limitations of the proposed techniques are illustrated through example problems.