Abstract
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 this paper, the fundamentals of the CED for an interface crack are studied. The concrete definition of the CED for an interface crack is given first, and it is shown that the CED can be divided into mode I and mode II contributions that can be expressed by domain integrals without any restrictions on the constitutive equation. Subsequently, the relationships to the conventional crack parameters of the CED are derived. Moreover, the substantial mode I and mode II contributions of the energy release rate are introduced, and their correspondence to the mode I and mode II contributions of the CED is discussed.
