Experimental investigation and numerical simulation of interfacial crack kinking in foam core composite sandwich beams

The interfacial crack kinking paths in glass fiber reinforced composite sandwich beams were experimentally investigated with double cantilever beam (DCB) specimens, and a series of polymethacrylimid (PMI) foam core with different densities was considered. According to the specimens numerical models were built by material point method(MPM). Mode mixity and kinking angle were calculated with different facing-to-core modulus ratio, and crack kinking paths were simulated. A good accordance was found between numerical results and experimental observations which demonstrates that the MPM algorithm and numerical model presented in this paper is efficiency and accuracy. The result indicates that if kinking occurs bigger kinking angle will be obtained with stronger facing-to-core modulus mismatch, and after kinking into the core the crack will propagate parallel to the face/core interface because the loading becomes highly mode Ⅰ dominated.