Finite Element and Boundary Element Models for Predicting the Vibro-Acoustic Behaviour of Multi-Layered Structures

Layered structures made from elastic and porous materials are widely used as insulation systems in the automotive industry. They have a complex dynamic behavior which is influenced by the various interaction mechanisms within the porous material. The paper concentrates on modeling these systems using a 3-D finite element (FE) approach for the structure combined with a boundary element (BE) procedure for the acoustic radiation process. The key part is a Biot's model for the two phase porous material. A mixed displacement formulation is selected. The model can be used for predicting the surface impedance and/or the transmission loss characteristics of layered material. The combined use of this FE/BE model enables the evaluation of the acoustic response (radiated power, field pressure). Numerical applications are presented in order to show the capabilities of the developed procedures.