Ranking subsystem targets according to their influence on system performance

Large, complex systems are often decomposed into several subsystems that are designed in parallel. This process requires specifying a design target yields an overall system with satisfactory performance. Methods for setting and balancing subsystem targets were described in previous publications (H. Mahmoud, et.al. May 2002), (H. Mahmoud, et.al. November 2002). Addresses the question of how to rank, or set priorities on, different subsystem design targets according to their influence on overall system performance. The present work quantifies the influence of changes in the different subsystem design targets on overall system performance. Calculating the sensitivities of system-level performance with respect to subsystem targets rather than design variables, as traditionally done in the design literature, is a key component of the present study. The proposed procedure for ranking subsystem targets will enable product design teams to commit their engineering resources towards modification of only those subsystem targets that will bring about the greatest improvement in overall system performance. The present study deals specifically with noise, vibration and harshness (NVH) design targets.