Automatic Modelling of Mixed-Mode Fatigue and Quasi-Static Crack Propagation Using the Boundary Element Method
SourceA multidomain boundary element model for the automatic analysis of mixed-mode fatigue and quasi-static crack propagation problems is described. Starting with the initial structural discretization, the new model automatically computes stress-intensity factors, direction of propagation, and load increment or number of cycles required to advance the crack tips a requested distance. This process is repeated, again automatically, until crack instability occurs or the requested number of crack increments is reached. Traction singular quarter-point boundary elements are used on each side of the crack tips. These elements contain both the dominant 1/√r traction singularity and the dominant √r displacement variation at the crack tip. Any of four mixed-mode interaction theories may be activated for angle and instability predictions. Solutions of example problems are presented. The predicted boundary element results show good correlation with both experimental and other numerically obtained results.