DESIGN SENSITIVITY ANALYSIS AND OPTIMIZATION OF AN ENGINE MOUNT SYSTEM USING THE FRF-BASED SUBSTRUCTURING

摘要

A general procedure for the design sensitivity analysis of acoustic response function has been presented using the FRF-based substructuring formulation. The design sensitivity formulation is derived based on the governing equations of the FRF-based substructuring method. The derived noise sensitivity formula is combined with a nonlinear programming module to obtain the optimal design for an engine mount system of passenger car. The object function is the area of the interior noise graph over a concerned rpm range. The interior noise variations with respect to the dynamic characteristics of the engine mounts and bushings have been calculated using the proposed sensitivity formulation and transferred to the nonlinear optimization software. To obtain the FRFs, we use a finite element analysis for the engine mount structures and experimental techniques for the trimmed body including cabin cavity. The optimization based on the sensitivity analysis gives the optimal stiffnesses of the engine mount and bushings. The optimized interior noise in the passenger car shows that the proposed method is efficient and accurate.