Collapse mechanism analysis of foam-filled corrugated sandwich beams under in-plane compression

It is proposed to insert polymer foams into the interstices of the corrugated core and the collapse of foam-filled corrugated sandwich beams subject to in-plane compression is investigated analytically and numerically to enhance the in-plane compression structural stability of the corrugated sandwich constructions that will be used as a kind of novel lightweight hulls for high speed strains and oil tanks. Failure mechanisms such as global elastic/plastic buckling and elastic/plastic face wrinkling are taken into account. The equivalent elastic constants of the foam-filled corrugations based upon the homogenization approach are employed to calculate the critical failure load of global buckling, and analytical formulae of face wrinkling are given by treating the foam insertion as Winkler-type elastic foundation. A failure mechanism map is constructed by using the material properties of 304 stainless steel and Rohacell 51 foam, and then three different constructions are designed to numerically probe different failure modes. It is shown that the analytical predictions accurately capture both the critical failure load and the failure mechanism. The minimum weight optimization design to foam-filled corrugated sandwich beams subject to in-plane compression is carried out and compared with competitive structures to obtain the optimal geometrical dimension of structure. Comparisons on considering the features such as load bearing, energy absorption, vibration damping, heat insulation and other multi-functional characteristics show that the foam-filled corrugated sandwich has greater potential in engineering application over empty corrugated and pyramidal sandwiches.