Finite Element Analysis of Debonded Sandwich Beams under Axial Compression

A nonlinear finite element analysis was performed to simulate axial compression of sandwich beams with debonded face sheets. The load-end-shortening diagrams were generated for a variety of specimens used in a previous experimental study. The energy release rate at the crack tip was computed using the J-integral, and plotted as a function of the load.Adetailed stress analysiswas performed and the critical stresses in the face sheet and the core were computed. The core was also molded as an isotropic elasticperfectly plastic material and a nonlinear post buckling analysis was performed. A Graeco-Latin factorial plan was used to study the effects of debond length, fact sheet and core thicknesses, and core density on the load carrying capacity of the sandwich composite. It has been found that a linear buckling analysis is inadequate in determining the maximum load a debonded sandwich beam can carry. A nonlinear post-buckling analysis combined with an elasto-plastic model of the core is required to predict the compression behavior of debonded sandwich beams.