Transmission loss through barriers lined with heterogeneous porous materials

Abstract

The effect of solid heterogeneities and acoustic cavities on the normal incidence transmission loss of heterogeneous porous materials inserted in an infinite rectangular waveguide is investigated. The model is based on a finite element Biot-Allard's formulation for the porous patches. The modal behavior of the waveguide accounts for the coupling between the porous material and the waveguide. Numerical results are presented regarding the effect of geometric and physical parameters on the transmission loss performance of highly resistive plastic foam.