A NUMERICAL STUDY ON THE CRACK-GROWTH BEHAVIOR OF A LOW AND A HIGH-STRENGTH STEEL

Geometry and size effects on the crack growth resistance curves in CT- specimens of a low and high strength material are numerically investig ated. The fracture process is controlled by experimentally determined critical values of the crack tip opening displacement (CTODi) for crac k growth initiation and the crack tip opening angle (CTOA(C)) for stab le crack growth. The results show that for the low and the high streng th material the geometry and size effects are different. This is mainl y due to the fact that the load vs. load line displacement records are basically different for the two materials which results from the larg e difference in the scaled fracture toughness parameters, CTODi/epsilo n(0) and CTOA(C)/epsilon(0), of the two materials.