Extraction of Stress Intensity Factors for the Simulation of 3-D Crack Growth with the Generalized Finite Element Method

Two methods for the extraction of Stress Intensity Factors (SIFs) from three-dimensional (3-D)problems are presented: the Contour Integral Method and the Cutoff Function Method. The formula-tions are tailored for the Generalized Finite ElementMethod andmixed-mode 3-D propagating cracks.The case of crack faces loaded by prescribed tractions is also considered. Another contribution of thispaper is a procedure to control the noise of extracted SIFs based on theMoving Least SquaresMethod.The proposed approach provides a continuous and smooth approximation of 3-D SIF functions foreach fracture mode. Numerical experiments demonstrating the accuracy and robustness of the pro-posed methodology are presented. They include 3-D mixed-mode fatigue crack growth simulationsand the case of a pressurized crack.