Crack Energy Density on a 3-Dimensional Crack : Series A : Solid-Mechanics, Strength of Materials

Crack energy density is the parameter which is defined clearly, without any restriction on constitutive equation, throughout the life of a crack and is expected to successfully describe all kinds of behaviors of a crack. So it may well be thought that the parameter is defined reasonably for a 3-dimensional crack. The purpose of this study is to indicate the property of crack energy density on 3-dimensional cracks for evaluation of this parameter. The contents of this report are as follows. (1) Define crack energy density on a 3-dimensional crack by using two crack models, and make it clear that the value of crack energy density is determined independently of coordinate system and plane on which the integral path is set. (2) Define crack energy density as a path-independent integral, and compare it with the J-integral of a 3-dimensional crack. (3) Propose a method to estimate the value of crack energy density from load-displacement curves.