Mode II interfacial fracture characterization of foam core sandwich materials at elevated temperatures: the effects of frictional stresses between the crack edges

In recent years, composite sandwich material has been widely used in civil engineering due to its high strength to weight ratio, high stiffness to weight ratio and anti-corrosion ability. However, the existing research studies indicated that interfacial delamination between skins and core was a common failure mode for this kind of material, which seriously threatens the durability and safety of structures. Furthermore, up to now, there are no research studies investigating the effects of elevated temperature on the interfacial fracture and damage behavior of the sandwich material. To address the above questions, this paper investigated the effects of elevated temperature on mode II interfacial fracture response of foam core sandwich materials by adopting the end-notched flexure method. Test results showed that the loads and the strain energy release rate decreased under the same crack length as the temperature increased. In the meantime, the corresponding analytical model, considering the effect of frictional stresses between the crack edges, has been proposed to predict the interfacial strain energy release rate. The comparison of the analytical and experimental results revealed that the analytical model could accurately predict the strain energy release rate of mode II interfacial fracture of foam core sandwich materials at elevated temperatures.