Evaluation of Crack Energy Density by Using E_J-integral in case of Elasto-plastic and Creep Crack

Abstract

In former papers, the concept of crack energy density ε has been proposed as the most fundamental parameter in fracture mechanics and it has been shown that ε can be evaluated by path independent integral ε_J under arbitrary constitutive law. In this paper, the expressions of ε_J-integral which evaluate each contribution of elasticity, plasticity and creep to total crack energy density ε and the distribution of crack energy densities are newly introduced and these are applied to elasto-plastic and creep crack problems. Finite element analyses are carried out, the fundamental characteristics of ε in continuum model are quantitatively discussed and a method for evaluating ε by ε_J-integral is established through these analyses.