Scaled boundary finite element method for an acoustic cavity with porous layer

In this work, the scaled boundary finite element method (SBFEM) is used to predict the frequency response of an acoustic cavity with a porous layer based on Biot-Allard theory. For the porous material, both the solid and the fluid displacements are considered as the primary variables. Scaled boundary shape functions are used to interpolate the acoustic pressure within the acoustic cavity, and the solid and fluid displacements in the porous material. The material matrices of the porous material are decomposed in such a way that the elemental matrices are real and frequency independent. This allows the elemental matrices to be computed and stored for a given mesh and is used for each frequency increment thus reducing the number of computations. Numerical examples are presented to show the computational efficiency of the SBFEM in predicting the frequency response of a porous material excited with acoustic cavity.