Influence of Surface Porosity on the Radiated Sound From Multilayer Automotive Trim Components 2005-01-2345

Lightweight porous automotive acoustic multilayer trim components have been traditionally specified in terms of sound absorption and sound transmission loss performance targets. These targets are valid for airborne noise excitation only, in the medium to high frequency ranges. Unfortunately, this neglects the fact that in real-world vehicle applications, these components are also subjected to low-medium frequency structural vibration inputs from the mechanical components of the vehicle, which is typically an acoustic sound radiation problem.

This article then presents new physically-based Finite Element (FE) numerical simulation developments, which allow the prediction of the surface sound radiation of porous multilayer trim components. Here, the methodology is fully convergent, respects the anisotropic mechanical properties of manufactured porous foams and fibrous materials, and addresses the complex interfaces between materials in the multilayer. The approach is shown to be particularly effective in helping to optimize the mechanical, damping and surface porosity properties of the material layers of lightweight porous trim components minimal low-medium frequency sound radiation performance, which is primarily relevant for structural vibration excitation input.