CED for an Interface Crack (2nd Report, A Study Based on Elastic Finite Element Analyses)

The fracture parameter of an interface crack has yet to be established even for an elastic crack. The CED (crack energy density) was proposed as a crack parameter which enables us to be free from the restrictions on the constitutive equation, and it has been shown that it is applicable, in a unified way, to various kinds of crack behavior in a homogeneous material. Therefore, the CED may also be applicable to an interface crack. In the previous paper, the fundamentals of the CED for an interface crack were studied theoretically. In this paper, the elastic finite element analyses of a bimaterial specimen with a center crack in the interface are carried out under tension, and it is shown that the CED and its mode I and mode II contributions can be evaluated from the corresponding domain integrals virtually independent of the radius of curvature p at the notch (crack) tip over the some range of ρ and, therefore, these quantities are promising as crack parameters of an interface crack. Moreover, the substantial mode I and mode II contributions of the energy release rate introduced in the previous paper are evaluated and the relationships of the mode I and mode II contributions of the CED to them are discussed.