Development of a hybrid MDF/IDF multidisciplinary optimization solution method with coupling suspension

Multidisciplinary Design Optimization (MDO) is a discipline, which solves complex engineering systems by decomposing them into a set of subsystems. Couplings connect these subsystems together, illustrating the passage of information from one subsystem to another. These couplings result in the increase in time and cost of the execution of the MDO cycle. Subsystem reordering, coupling suspension and coupling elimination are a few methods used for reducing time and cost of execution. Previous research in coupling suspensions shows that due to the reduction in couplings an error is introduced into the solution with a possibility of divergence of the design. Hybrid MDF/IDF is a MDO solution method developed in this work, which reduces the error introduced by coupling suspension in the subsystem outputs and the final value of the objective function. The Hybrid method is a compromise between the MDF and IDF solution methods. The method reduces the error by adding equality constraints for the subsystem outputs affected by the suspension of couplings. These equality constraints restrict the path of the solution and direct it towards the solution attained by unsuspended analysis.