Efficient optimization of a noise transfer function by modification of a shell structure geometry - Part I: Theory

In the early stages of vehicle body development trends for the acoustic behaviour of the whole vehicle are, on the one hand, of great importance, but difficult to achieve. Geometry based, parametric model descriptions and optimization techniques enable the engineer to find out these trends. This paper starts with a review of structural acoustic sensitivity analysis and optimization. Then, the noise transfer function including structural harmonic analysis, acoustic influence coefficients and their coupling is described. This is followed by some remarks on the optimization process, discussing objective functions, useful design parameters and optimization techniques. Finally, a section on sensitivity analysis presents a numerical and a semianalytic method. In the case of small design modifications the sensitivity calculation mainly reduces to the well-known semianalytic calculation of harmonic displacement sensitivities. Part II presents the design optimization of a sedan dashboard.