Postbuckling response of long thick plates loaded in compression including higher order transverse shearing effects

This paper presents buckling and postbuckling results for compression-loaded simply-supported aluminum plates and composite plates with a symmetric lay-up of thin +/-45-deg plies composed of many layers. Buckling results for aluminum plates of finite length are given for various length-to-width ratios. Asymptotes to the curves based on the buckling results give N(XCr) for plates of infinite length. Postbuckling results for plates with transverse shearing flexibility are compared to results from classical theory for various width-to-thickness ratios. Characteristic curves indicating the average longitudinal direct stress resultant as a function of the applied displacements are calculated based on four different theories: classical von Karman theory using the Kirchhoff assumptions, first-order shear deformation theory, higher-order shear deformation theory, and three-dimensional flexibility theory. Present results indicate that the three-dimensional flexibility theory gives the lowest buckling loads. The higher-order shear deformation theory has fewer unknowns than the three-dimensional flexibility theory but does not take into account through-the-thickness effects. The figures presented show that small differences occur in the average longitudinal direct stress resultants from the four theories that are functions of applied end-shortening displacement.