Layered structures made from elastic and porous materials are widely used as insulation systems in the automotive industry. They have a dynamic behavior which is strongly influenced by the various interaction mechanisms within the porous material. The paper concentrates on modeling such materials using a 3-D finite element (FE) approach. This model can be combined with a boundary element (BE) procedure in order to assess the radiated acoustic field. The key part of FE representation 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 acoustic transmission characteristics of layered materials. The combined use of this mixed FE/BE model enables also the evaluation of the acoustic response (radiated power, field pressure).