Experimental Determination of Crack Driving Forces for Small Cracks

The crack tip field of small fatigue cracks was measured using digital image correlation DIC. For this purpose, smooth specimen were fatigued until a certain amount of damage was visible on the surface. This specimens were then placed in a micro-tensile device in the SEM. The grey value patterns obtained at two different load levels were analyzed with DIC. Fitting the Williams series for the crack tip field to the corresponding DIC-displacement...