Vibroacoustic FE Simulations of Automotive Insulators: Automatic Meshing Tool for Fast Modeling

Vibroacoustic simulations of automotive trim parts (dash, carpets, headliners…), including poroelastic materials like foam, felt, non-woven or textile, cannot be easily performed due to the curvature effect from both car structure and part shape. If Finite Transfer Matrix Method (FTMM) based computations are very fast and useful tools to rank and compare technical solution, they are unable to fit with insulation TL measures: whereas classical “mass-spring” flat system are showing a 12dB/oct Insertion Loss (IL) slope, experimentally a “mass-spring” dash yields a typical 8-9dB/oct slopes, due to the curvature effect.
To circumvent this problem, in low and middle frequencies, BEM/FEM (Boundary Elements Method / Finite Elements Method) approaches are the most efficient. Nowadays, despite of the growing performances of both commercial software solvers and computing facilities, meshing time of trim parts hinder FEM/BEM computations with poroelastic materials from being run in design and development phases of new vehicles. So this kind of computations remains most often limited to advanced engineering phases or research work.
To accelerate meshing phase of acoustic insulators, an Automatic Meshing Tool was developed and successfully tested regarding industrial cases. This way, meshing time can be drastically reduced, while keeping an accurate prediction of the vibroacoustic performances of the part. In this paper, the Automatic Meshing Tool is presented and applied on poroelastic models coming from real industrial cases. The latter follows the actual process constraints of each multi-layer insulator technology.