The study of sound transmission through sandwich cylindrical shells with circumferentially corrugated cores filled with porous materials

Abstract

This paper presents an analytical study on the sound wave propagation across a sandwich cylindrical shell with a corrugated core filled with porous materials. The outer layer is subjected to oblique plane waves, and a subsonic flow is traveling in the exterior medium. To describe the porous medium, the extended full method (EFM) is employed, which calculates the displacement and stress fields across the layer. Next, the corrugated core is modeled as a series of translational and rotational springs, and the mass of the core is uniformly distributed on the inner and outer isotropic shells. Besides, the first-order shear deformation theory is used to model the dynamic response of the isotropic layers. The proposed formulation is validated by comparing the current approach to previous studies on the proposed literature. The vibroacoustic effects of various parameters, such as porosity, types of the porous materials, the thickness of the corrugated core, structural damping factor, incident angle, and Mach number of the external flow, are analyzed. Also, the sound insulation capability of the structure with and without the porous medium is carefully studied.