Simple Stress Substitution Approach for Computation of Stress Intensity Factors of Face-Loaded Cracks

摘要

The accurate computation of stress intensity factors (SIFs) of face-loaded cracks is of significant importance for engineering practices. Based on the analytical stress field of a central crack in an infinite plane subjected to a pair of crack-face concentrated forces, a simple stress substitution approach that replaces the unknown actual stress field by that of the Williams' solution for traction-free cracks is proposed and used in conjunction with the subregion generalized variational principle and quadrature element method (QEM) for computation of the SIF. This approach is validated by a series of representative problems, including different crack configurations and loading conditions. The comparisons between the analytical or approximate solutions and the numerical results suggest that the approach produces reasonably accurate SIFs when the size of the complementary energy subregion is confined to be 0.2-0.3 times the (half) crack length, even with the coarsest mesh. The accuracy can be further improved by smaller subregion size and smaller elemental maximum aspect ratio.