Three-dimensional finite element simulation of post-yield fracture experiments

It is shown that the evaluation of the J-integral by the virtual crack extension method gives "path-independent" results and is equivalent for 2D problems to the contour-integral evaluation also with significant load relief due to crack extension, provided the stress work density W is defined appropriately. Despite encouraging results concerning the application of 3D finite element procedures to complex structures there remains the problem to quantify the influence of the local stress state on the material resistance against crack propagation. (IWM)