抄録
In this paper, when the initial propagation angle of branched crack is calculated from the maximum tangential stress criterion (MTSC) and the minimum strain energy density criterion (MSEDC), we had better use stress components in which higher order terms are considered and stress components at the position in a distance 0.005mm from the crack tip (= r). When interfacial crack propagates along the interface with constant velocity, the initial propagation angle of branched crack is similar to the mode mixity and the theoretical values obtained from MTSC and MSEDC. The initial propagation angle of branched crack is considerably depended on the stress intensity factor K_2.