Wave propagation analysis of a ceramic-metal functionally graded sandwich plate with different porosity distributions in a hygro-thermal environment

Wave propagation analysis of porous functionally graded (FG) sandwich plate in a hygro-thermal environment is presented in this paper. The sandwich plates’ composing materials change through three layers that are either homogeneous ceramic, homogeneous metal, or power-law-based functionally graded ceramic–metal. Six different porosity models are considered in the analysis to express the porosities’ distribution factor and uniformity. The study is conducted using a simple four-unknown integral higher-order shear deformation theory (HSDT). The effect of moisture and temperature on wave propagation in porous FG sandwich plates is investigated by considering their role on the materials’ expansion. The governing equations are derived for the wave propagation problem based on the presented theory via Hamilton's principle. A generalized solution for wave propagation is applied to formulate the stiffness and mass matrix that describes the dispersion relations. The numerical results are obtained by solving an eigenvalue problem. The effects of core-to-thickness ratio, FGM power index, porosity volume fraction, temperature, and moisture change are illustrated and discussed. The presented results can be utilized as a benchmark for further studies on wave propagation in FGM plates.