Static deflections and stress distribution of functionally graded sandwich plates with porosity

In this paper a higher-order shear deformation plate theory is presented to investigate the stress distribution and static deflections of functionally graded sandwich plates with porosity effects. The displacement field of the present theory is chosen based on nonlinear variations in the in-plane displacements through the thickness of the plate. By dividing the transverse displacement into the bending and shear parts and making further assumptions, the number of unknowns and equations of motion of the present theory is reduced a and hence makes them simple to use. The functionally graded materials (FGM) used in plates contain probably a porosity volume fraction which needs taking into account this aspect of imperfection in the mechanical bahavior of such structures. The present work aims to study the effect of the distribution forms of porosity on the bending of simply supported FG sandwich plate. The governing equations of the problem are derived by using the principle of virtual work. In the solution of the governing equations, the Navier procedure is used for the simply supported plate. In the porosity effect, four different porosity types are used for functionally graded sandwich plates. In the numerical results, the effects of the porosity parameters, porosity types and aspect ratio of plates on the normal stress, shear stress and static deflections of the functionally graded sandwich plates are presented and discussed. Also, some comparison studies are performed in order to validate the present formulations.