Stress singularity evaluation for three-dimensional cracks using characteristic tensor method

Abstract

The Characteristic tensor method (CTM) is a new method to evaluate the singular stress field with a characteristic tensor (CT) which is calculated by averaging the stress in an infinitesimal volume at a crack tip. The CT has a linear relation with the stress intensity factor (SIF), which characterizes the singular stress field around a crack tip in an isotropic homogeneous elastic body. Even under mixed-mode loading conditions, the SIFs of each mode can be easily and efficiently estimated using CT. For the practical use in industries, the evaluation of the CTM for a three-dimensional crack under general three-dimensional stress state is necessary. In this study, the reliability and accuracy of CTM is investigated by estimating SIFs in several representative types of three-dimensional cracks where stress states are calculated by the finite element method. The results show that the SIFs estimated by the CTM have high accuracy even for mixed-mode conditions. It was, thus, demonstrated that CTM provides a practical and reliable approach for the efficient estimation of SIFs of three-dimensional cracks.