By use of finite element analysis method of elastic-plasticity, a calculation of M-integral for 7075 aluminum alloy plate containing different configuration defects was conducted. The effect of plastic energy on path independence of the M-integral is discussed, The variation of M-integral of the holes before and after coalescence under tension loading is studied. Analysis result indicates that M-integral will be path dependent when the plastic zone is passed through by the selected integration contours. There is a jump of the M-integral when coalescence of the holes in a plate occurs. The value of the M-integral is always configuration dependent.
By use of extended finite element analysis method, a calculation of J-integral for interface crack on Micro-arc Oxidation(MAO) ceramic coating on aluminum alloy was conducted. The feasibility of using J-integral as a fracture parameter to characterize the interfacial fracture toughness is discussed. The relation between J-integral and length of interface crack, thickness of ceramic coating is studied. Analysis result indicates that with the expansion of the interface crack length, resistance bi-material interface enhancements, and interfacial fracture toughness enhances, the J-integral increases with the increase of crack length. When the thickness of the ceramic coating is upon 40μm-100μm, interfacial fracture toughness is better. J-integral value shows a decreasing trend with the increase of the thickness of the ceramic coating.