Free vibration analysis of imperfection FG sandwich panel with piezoelectric face sheets using new hyperbolic theory

In this study, the effect of material imperfection on the free vibration response of FG sandwich panel with piezoelectric face sheets is studied. A new hyperbolic shear deformation function is presented in this paper. The properties of the FG core varied along the thickness according to power law. The material composition in production process cannot be completely in accordance with the expected pattern, which leads to the production of imperfect FG material. Hence in this research, one perfect model and two types of imperfect models have been considered. The governing differential equations are derived using the Hamilton’s principle and solved using the Navier method. The effects of important geometric and mechanical parameters of perfect model and two types of imperfect model including thickness to length ratio, length to width ratio, FGM core to piezoelectric layer thickness ratio and electrical potential on natural frequency response of imperfect FG sandwich panel with piezoelectric face sheets are investigated. To verification, the analytical results obtained in this study are compared with the results presented in the literature, and in this comparison, a good agreement was obtained, which shows the correctness theory, deriving and solving equations.