Transmission loss assessments of sandwich structures by using a combination of finite element and boundary element methods

Abstract

In this work, formulation of a 2D fully‐coupled finite element method (FEM)/boundary element method (BEM) to simulate the measurements of sound transmission loss of sandwich panels is presented. Specifically, the structural behavior of the sandwich panels, based on a consistent higher‐order theory, is implemented using finite element method (FEM), and the reverberant/anechoic chambers are accessed by boundary element method (BEM). The coupling between the structure and the acoustic medium is achieved by assuming the continuity of the normal velocities at the interface. The absorption of the receiving anechoic chamber is calibrated by comparing the numerically‐predicted sound pressure level difference between the two chambers with the Sewell’s expression for the forced transmission. The obtained correction factors are then used without any modification to predict transmission loss of other sandwich panels with different dimensions and material properties. Numerical examples are presented to validate the numerical procedure. Compared with traditional finite element approach, the proposed hybrid method provides more computation efficiency, and, hence, can be used to study acoustic behavior of sandwich panels at higher frequencies.