Numerical Simulation of Fatigue Crack Growth for Corner Cracks Emanating from Fastener Holes

Fatigue crack propagation for corner cracks emanating from fastener holes in plates under cyclic tension loading has been investigated. A numerical technique, which is able to simulate the crack shape evolution directly and to obtain more accurate estimates of fatigue lives, has been used. The technique calculates the local growth increments at a set of points defining a crack front by employing a Paris type of fatigue growth law, and permits the crack to grow automatically. The fatigue analysis is focused on the growth simulation for several assumed initially quarter-elliptical corner cracks at three fastener holes of different hole radius. An initially irregular crack is also simulated to examine its shape development characteristic. A wide range of numerical results is obtained, such as aspect ratio changes, crack shape developments and characteristics of stress intensity factor variations during crack growth. Moreover, the fatigue tests reported by Grandt-Macha and Shin are also simulated numerically by the present technique to validate the technique. Comparison is performed between the numerical and experimental results for the aspect ratio and the number of fatigue growth cycles.