Acoustic Analysis of Partially Flexible Cavity with Opening

In this study, the SPL at the boundary and within the domain of a rectangular-shaped container with a flexible laminated composite panel with opening have been investigated. Finite Element Analysis (FEM) for the flexible panel has been done and coupled with the acoustic domain using the Boundary Element Method (BEM) through the mobility relation. A MATLAB program has been developed to find flexible panel behavior by FEM and BEM to calculate the sound pressure level for a cavity. Eight-noded isoparametric serendipity elements have been used to model the boundary. A pressure-velocity formulation has been adopted to model the acoustic domain with radiation impedance for window boundary. It has been shown that the presence of a thin flexible plate and opening, drastically changes the SPL pattern inside and at the boundary compared to a rigid cavity due to the relative movement of flexible panel and energy dissipation through the opening by radiation.