Advanced Modeling Approaches for the Evaluation of Interior Vehicle Acoustics over the Full Range of Frequencies

Stringent legislation by governmental agencies concerning human exposure to noise and vibrations on the one hand and the growing consumer awareness and need for comforts on the other hand are forcing automotive manufacturers to improve their products. Computer Aided Engineering (CAE) techniques and software tools enable virtual optimization thereby eliminating the need to build and test expensive prototypes. Deterministic, element-based approaches as the Finite Element (FE) and/or Boundary Element (BE) methods have become the tools of choice for analyzing the steady-state and dynamic characteristics of vehicles. However, these two techniques are limited to low-frequency applications due to the need for high mesh densities at mid and high frequencies resulting in higher computational costs and higher numerical errors associated with the polynomial approximations of the acoustic field variables.

This paper discusses two types of approaches, viz. Finite Element Method (FEM) and Statistical Energy Analysis (SEA) aimed at stretching the computation range to mid-frequency and beyond. State-of-the-art numerical solution schemes are reviewed for their capability to solve the huge FE systems of linear equations that are needed to capture the dynamic behavior of acoustic cavities. A short description on the recent advances in solvers for acoustic FE simulation is included. Both method types are demonstrated on an industrial case, and assessed in terms of accuracy and computational cost over the whole frequency range.