A new unified modeling of acoustically-coupled multilayers by (u s,u W) displacement formulation based poroelastic transfer matrix

Abstract

This paper is devoted to propose a new unified modeling technique to efficiently present acoustically-coupled multilayers consisting of air, elastic and poroelastic layers. The present work is motivated by a need for more efficient modeling in multilayer design optimization, such as topology optimization. A poroelastic transfer matrix derived from Biot’s theory is employed for a unified modeling of multilayers. The existing unified modeling approaches were derived by the field variables of the solid- and fluid-phase displacements. In this work, the solid-phase displacement (u s) and a compound form (u W) of the solid- and fluid-phase displacements are used as the generalized coordinates to develop a new unified modeling technique. When the alternative formulation is used, the physics of wave propagation in multilayers can be better explained. Moreover, it also allows the macroscopic material coefficients to be directly controlled for the design optimization applications compared with the existing unified modeling techniques.