Interactive Buckling of Sandwich Plates Under Compression

Abstract

Compressive behavior of two classes of “sandwich” structures is investigated. These structures have for their principal load bearing components two relatively stiff parallel horizontal sheets which are interconnected in one of the following ways: (i) by a highly compliant core material such as foam, or (ii) a set of discrete stiffeners connecting the parallel (top and bottom) sheets. In case (i), the structure can buckle in either a local mode in which the core and the facing bend together or a wrinkling mode in which the facing sheet undergoes severe bending with the core subjected to deformation in the transverse plane. It is found that these plates have neither post buckling stiffness nor do they exhibit any imperfection-sensitivity. In case (ii) the point of principal interest is the interaction of local and overall buckling. For the case of coincident local and overall buckling, it is found that 30% reduction in the maximum load can occur for modest levels of imperfections as a result of modal interaction.