圧子圧入試験のための界面弾性J積分

抄録

In advanced material such as composite and coatings, interfacial crack initiation and propagation, which are caused by mechanical and thermal loadings, are serious problem. A lot of interfacial fracture testing methods have been proposed to evaluate the adhesive strength of those advanced materials. However, there are some difficulties when those proposed testing methods are utilized because of restriction of the specimen geometry, of fracture loading direction, and so on. Especially, the stress field at the interface under an actual loading is known to be in mode-II load condition, which gives us motivation to do this study. In this study, simple interfacial fracture testing method is proposed. In the proposed method, the ridged indenter is just indented on the sample surface, which leads easily to the interfacial crack under mode-II condition, and the interfacial fracture toughness can be easily estimated from both indentation depth and interfacial crack size. The closed formula to estimate interfacial elastic J integral as the interfacial fracture toughness is obtained based on stress function and variation of energy released by crack propagation with a help of the FEM results by using domain integral technique installed in commercialized finite element code MARC. The indentation tests are conducted to check verification of the interfacial fracture toughness by the proposed test method for Aluminum alloy / PMMA combination samples.