Crack Kinking Criterion for Bimaterial System
This paper is aimed to find out a suitable criterion for predicting the interfacial crack in the bimaterial system. An investigation was undertaken into the interfacial crack kinking phenomena in a bimaterial specimen of epoxy and aluminum alloy using a combination of experimental method and numerical simulation. It was found that all kinked fractures occurred at loading angles equal to or larger than 120°, so the kinking direction heavily dependeds on the loading mode mixity. Three categories of fracture pattern were identified (A, B and C). In the case of type A fracture, the (J10)kink integrals were generally higher than the homogeneous epoxy Jic at loading angles of 120° and above. In contrast, for types B and C fracture, the J10 integrals were consistently lower than the homogeneous epoxy Jic. Predictions of crack kinking behavior made using the Maximum Energy Release Rate Criterion (MG-criterion) were found to agree well with the observed experimental results. The kinked deformation of crack tip observed by moire´ interferometry, is well agreed with the result of numerical simulation.