Buckling of laminated sandwich plates with soft core based on an improved higher order zigzag theory

An improved higher order zigzag theory is presented and it is applied to study the buckling of laminated sandwich plates. The present theory satisfies the conditions of transverse shear stress continuity at all the layer interfaces including transverse shear stress free conditions at the top and bottom surfaces of the plate. The variation of in-plane displacements through thickness direction is assumed to be cubic for both the face sheets and the core, while transverse displacement is assumed to vary quadratically within the core but it remains constant over the face sheets. The core is modeled as a three-dimensional elastic continuum. An efficient C0 finite element is proposed for the implementation of the improved plate theory. The accuracy and range of applicability of the present formulation are established by comparing the present results with 3D elasticity solutions and other results available in literature.