Quantification and Use of System Coupling in Decomposed Design Optimization Problems

Abstract

Decomposition-based optimization strategies are used to solve complex engineering design problems that might be otherwise unsolvable. Yet, the associated computational cost can be prohibitively high due to the often large number of separate optimizations needed for coordination of problem solutions. To reduce this cost one may exploit the fact that some systems may be weakly coupled and their interactions can be suspended with little loss in solution accuracy. Suspending such interactions is usually based on the analyst’s experience or experimental observation. This article introduces an explicit measure of coupling strength among interconnected subproblems in a decomposed optimization problem, along with a systematic way for calculating it. The strength measure is then used to suspend weak couplings and thus improve system solution strategies, such as the model coordination method. Examples show that the resulting strategy can decrease the number of required system optimizations significantly.