The distribution of the elastic strain-energy density at the crack tip for fracture modes I and II

Abstract

The study of the distribution of the elastic-strain energy density at the tip of a crack presents a special interest for the understanding of the mechanism of fracture. In this investigation an exhaustive theoretical analysis of the distribution of the elastic-strain energy density at the tip of a crack for cracks in isotropic elastic media deformed under modes I and II was developed. This study was complemented by an experimental solution of this type of problem, based on the method of reflected caustics. According to this method the distribution of the elastic-strain energy density was evaluated along a circular closed curve, defining the singular core around the crack-tip, which was dominated by the singularity at the crack tip and whose diameter is very small, not exceeding a few millimeters. In this way the situation at the crack-tip singularity was directly depicted on the energy density distribution. Interesting results concerning the factors influencing the mode of the strain energy distribution around the crack and the type of the crack path were derived.