Failure analysis of brazed sandwich structures with square honeycomb-corrugation hybrid cores under three-point bending

In this work, the bending stiffness, initial failure load, initial failure modes and minimum mass design of square honeycomb-corrugation hybrid core sandwich structures (SHCH) subjected to bending were explored by a combined theoretical analysis, experimental testing, and numerical prediction method. Samples were fabricated by brazing process and measured under three-point bending. To theoretically obtain the initial failure mechanism map, six different initial failure modes were taken into account, which agree well with associated experimental data and numerical results. It is found that honeycomb filler not only changed the failure mode of corrugated core sandwiches but also enhanced dramatically its bending resistance. Then the minimum weight design is achieved as a function of load index, and the effect of key factors, including honeycomb relative density, loading platen width, material parameters, and inclination angle are quantified. Furthermore, the mechanical performances of SHCHs are compared with the competing structures.