Impact of door dynamics on vehicle interior low-frequency vibro-acoustics.

Interior acoustics represent an essential component of driving comfort in electric vehicles. Numerical simulation is an effective approach for assessing design concepts and enhancing acoustic performance. However, a fully coupled vibro-acoustic model for an entire vehicle remains computationally infeasible. Our approach couples mechanical and acoustic modal models on non-conforming interfaces in the low-frequency range, allowing independent mode combinations. Modal coupling reduces the computational effort significantly from full-order systems with millions of degrees of freedom to a selection of modes of the acoustic and mechanical systems. Modal models of the vehicle structure are derived from laser-vibrometer measurements while the interior acoustics are simulated numerically. Since laser measurements are restricted to the vehicle’s exterior surfaces and vibro-acoustic coupling occurs between the inner structural surface and the interior fluid, the structural behavior of the vehicle’s inner surface needs to be determined. We performed modal testing on both the exterior and interior surface of a front door within an entire vehicle due to hammer impact and volume source excitation. The modal structural behavior of the exterior and interior surfaces was analyzed for the frequency range of interest. We incorporated the modal descriptions of the measured door and the simulated fluid into our modal coupling approach to compare the resulting coupled system using only the exterior surface data versus the whole measurement information from both surfaces. Using the obtained system, we aim to reproduce the measurement data by calculating the acoustic pressure due to mechanical excitation and the mechanical displacement due to acoustic excitation.