Efficient broadband vibro-acoustic analysis of passenger car bodies using an FE-BASED component mode synthesis approach

The costliest part of computationally optimizing automobiles for Noise, Vibration and Harshness (NVH) is the frequency response calculation of very large finite element models. In general, NVH is treated as a fluid-structure interaction between the body and the car interior fluid volume. In this paper, some features of the current approach to NVH computations at BMW are elucidated. First, the equations of motion for a typical NVH problem will be derived using three different formulations, differential, algebraic and modal. Next, three numerical approaches for solving the large systems of equations (direct, modal and Automated Multi-Level Substructuring (AMLS)) will be shown. Finally, the numerical precision and the efficiency of these approaches will be assessed.