Thermal Postbuckling of Preloaded Shear Deformable Laminated Plates

Postbuckling analysis is presented for a simply supported, shear deformable laminated plate subjected to a uniform lateral pressure and thermal loading, and resting on an elastic foundation. The temperature fields considered are associated with a nonuniform tentlike and parabolic distribution over the plate surface. The material properties are assumed to be independent of temperature. The lateral pressure is first converted into an initial deflection, and the initial geometric imperfection of the plate also is taken into account. The formulations are based on Reddyʹs higher-order shear deformation plate theory and include the plate-foundation interaction and thermal effects. The analysis uses a mixed Galerkin-perturbation technique to determine the thermal postbuckling equilibrium paths. The numerical illustrations concern the thermal postbuckling behavior of preloaded antisymmetric angle-ply laminated plates under a tentlike temperature field and symmetric cross-ply laminated plates under a parabolic temperature field resting on Pasternak-type or softening nonlinear elastic foundations from which the results for Winkler elastic foundations are obtained as a limiting case. The effects played by foundation stiffness, fiber orientation, transverse shear deformation, the plate aspect ratio, thermal load ratio, and initial geometric imperfection as well as initial lateral pressure are studied.