Dynamic behavior analysis of vehicle acoustic trim using FEM

Multilayer vehicle acoustic trim containing poroelastic materials affects noise and vibration phenomena not only in the high-frequency range but also in the low and mid-frequency range. However, there are few established technology to analyze the vehicle model which includes the characteristics of the trim. In this paper, a methodology for the analysis of multilayer acoustic trim within a vehicle FEM model is derived based on Biot theory. Using this methodology, dynamic vibration, radiation and absorption behavior of three types of multilayer trim including conventional isolative type, absorptive type and isolative type with absorptive top layer backed by rectangular metal plates are analyzed. The trim model is also applied to a vehicle FEM model and its effects on interior sound pressure level are validated with experimental data.