SEPARATION OF EACH DEFORMATION MODE CONTRIBUTION FROM TOTAL CRACK ENERGY DENSITY AND ITS EVALUATION BY PATH-INDEPENDENT INTEGRAL.

Crack energy density is the parameter which is defined without any restriction on constitutive equation and is expected to successfully describe all kinds of behaviors of a crack. In this paper, the fundamental properties of crack energy density subject to mixed mode loading are discussed and, moreover, the evaluation of crack energy density by FEM is tried. The contents are as follows; 1) It is shown that total crack energy density in an arbitrary direction epsilon phi can be separated into each deformation mode contribution. 2) It is shown that epsilon phi and each deformation mode contribution can be expressed by path independent integrals without any restriction on constitutive equation. 3) The elastic finite element analyses of epsilon phi and each deformation mode contribution are carried out using path independent integrals for a specimen under tension with a crack inclined to the loading axis. Through the results of these analyses, the evaluation method of each deformation mode contribution of epsilon phi is discussed.