Modeling assessment and optimization of impacted multi-core sandwich composites

Applications are presented to multiple core sandwich composites undergoing impact loads. As structural models, a C° FSDPT plate model whose strain energy is updated to that of a refined 3D Zig-Zag model, and a mixed solid element with interlaminar stresses and displacements as nodal d.o.f. are considered. The first one is used within an optimisation process in order to find the distribution of the stiffness properties which minimizes the interlaminar stresses. The latter, which has the intra-element equilibria met in an approximate integral form, is used to assess the optimised solutions. It appears by this study the importance of modeling multiple cores sandwiches by refined structural models and the improved damage resistance of these materials offered by the present optimisation procedure.