VIBROACOUSTIC BEHAVIOUR OF CLAMPED DOUBLE-WALL PANELS LINED WITH POROELASTIC MATERIALS

This paper addresses analytically the vibroacoustic problem of sound transmission across a rectangular double-wall sandwich panel clamp mounted on an infinite acoustic rigid baffle and lined with poroelastic material. Biot's theory is employed to describe wave propagation in elastic porous media and various configurations based on the coupling method of the poroelastic material to the facing plate are considered. With the clamped boundary accounted for by using the modal super-position theory, a double series solution for the sound transmission loss of the structure is obtained by employing the weighted residual (Galerkin) method. The analytical model is validated against previous theoretical results of a single sound wave under normal incidence. The numerical results suggest that the poroelastic material and the clamped boundary have significant effects on the sound transmission loss and the panel deflection mode shapes. The configuration with two air gaps separating the porous layer from the facing plates exhibits the best overall performance on sound insulation.