Total derivative-based coupling suspension for system reduction in complex design

The design of complex engineering systems requires an initial decomposition of the system into subsystems. These systems are linked together by couplings, which relate the transference of output data from one subsystem to another. Because complex engineering systems can have hundreds or thousands of such couplings, the optimization of these systems is often quite lengthy. To reduce the optimization time, it becomes important that a system designer have the ability to select couplings that have little effect on the solution accuracy, to remove them either temporarily or permanently. Previous coupling strength analysis methods have not analytically related the effect of a coupling removal to solution accuracy. The method presented in this paper can be used to locate weak couplings based on their analytical relationship to the objective function and constraints in the overall optimization problem. The application of this new method is discussed, as well as the implementation on a decomposed analytical problem. The method significantly reduces the number of subsystem analyses required to optimize the decomposed problem by suspending couplings both permanently and temporarily.