Analysis of fracture behavior of honeycomb sandwich specimens

The flatwise tension test (FWT) and the double cantilever beam (DCB)experiment were used to investigate the fracture behavior of honeycomb sandwichspecimens. In the FWT test, not the interfacial debonding, but the interlaminardelamination was observed. So the test results show that the interfacial peelstrength is higher than the interlaminar peel strength. From the resultsof DCB experiment,a different fracture mode, namely IKP (initiation of interlaminar delamination,kinking into facesheet and propagation of interlaminar delamination), was found. Inorder to simulate the IKP of DCB honeycomb sandwich, a computational modelbased on the Tsai-Hill failure criterion and the cohesive zone model was proposed. Bycomparing with experimental results, it is shown that the computational model caneffectively simulate the IKP of a honeycomb sandwich structures with a reasonableaccuracy.