Postbuckling analysis of unilaterally constrained laminated thin plates

Postbuckling responses of laminated thin plates supported by a tensionless foundation and subjected to in-plane compressive edge loads are investigated. The postbuckling analysis presented here is based on the classical laminated plate theory, and includes the plate-foundation interaction, for which the foundation reacts in compression only. The plate is assumed to be simply supported at four edges, while the two longitudinal unloaded edges may be either movable or immovable. The initial geometric imperfection of the plate is taken into account. The analysis uses a two step perturbation technique to determine the postbuckling response of the plate. An iterative scheme is developed to obtain numerical results without any prior assumption for the shape of the contact region. The numerical examples concern the postbuckling behavior of antisymmetric angle-ply and symmetric cross-ply laminated plates with unilateral constraints, from which results for the same unconstrained plates are obtained as comparators. The numerical results show that the unilateral constraint has a significant effect on the postbuckling response of laminated thin plates.