Postbuckling of free edge Reissner-Mindlin plates elastically supported ona two-parameter foundation and subjected to biaxial compression and transverse loads

A postbuckling analysis is presented for a rectangular Reissner-Mindlin pla te with all four foe edges subjected to biaxial compression combined with a transverse central patch load and resting on a two-parameter (Pasternak-ty pe) elastic foundation. The lateral pressure is first converted into an ini tial deflection and the initial geometric imperfection of the plate is also taken into account. The formulations are based on Reissner-Mindlin plate t heory considering the first order shear deformation effect, including plate -foundation interaction. The analysis uses a mixed Galerkin-perturbation te chnique to determine the buckling loads and postbuckling equilibrium paths. Numerical examples are presented that relate to the performances of perfec t and imperfect, moderately thick plates with all four free edges under com bined loading conditions and resting on two-parameter elastic foundations f rom which results for Winkler elastic foundations are obtained as a limitin g case. The effects played by foundation stiffness, transverse shear deform ation, plate aspect ratio, loaded area parameter and initial lateral pressu re are studied. Typical results are presented in dimensionless graphical fo rm. (C) 2000 Elsevier Science Ltd. All rights reserved.