BUCKLING OF SANDWICH PANELS WITH A FLEXIBLE CORE-HIGH-ORDER THEORY

The buckling behavior of sandwich panels with a core that is flexible in the out-of-plane direction, also denoted as ''soft'' core including high-order effects, is presented. The buckling analysis consists of t he formulation of the linear and the nonlinear governing equations alo ng with the boundary conditions. The sandwich panel construction is ge neral and consists of two skin-panels, metallic or composite laminated symmetric that may be unidentical and a flexible isotropic or orthotr opic core made of foam or a low strength honeycomb. The analysis uses a high-order theory formulation, which permits nonlinear distortions o f the cross-section plane of the core as well as changes in its height . The analysis determines the bifurcation loads along with the associa ted mode shapes, local or overall buckling modes, as well as deformati ons, internal resultants and stresses al skin-core interface layers du e to imperfections. Numerical results using closed form solutions for simply-supported panels, with identical and non-identical skin-panels subjected to compressive inplane loads as well as imperfection analysi s results, are presented. The results reveal that, under some structur al configurations,the local buckling mode is a critical, rather than a global one as a result of the out-of-plane flexibility of the core. ( C) 1997 Elsevier Science Ltd.