Coupled loading hygro-thermo-mechanical Effect on the stability of imperfect functionally graded sandwich plates

In this research study, the hygro-thermo-mechanical responses of simply supported porous FG sandwich plates resting on a variable elastic foundation are studied by mean of a new height order shear deformation theory. The present model satisfies the nullity conditions of the shear stresses on the upper and lower surfaces of the FG plate and without using shear correction factors. The distribution of the properties of the material through the thickness of the sandwich plate is assumed to have a distribution according to a function of the power law, while the core is assumed to be purely ceramic. The derivation of the stability equations is obtained based on the principle of virtual works. The hygro-thermal loading is considered to have a uniform, linear and non-linear variation across the thickness of the plate. To verify the accuracy of the current model, a comparison was made with other authors of the literature. The effects of the hygro-thermo-mechanical loading, the porosity, the parameters of the elastic foundation « kw and kg », the thickness ratio « a/h », the aspect ratio « a/b » and the material index « k » on the critical buckling load of the FG plate are examined.