The influence on the crack growth rate for a short edge crack under fatigue loading due to changes in crack length, grain size, load range and grain boundary configuration, was investigated under quasi-static and plane strain conditions. The geometry was modelled by distributed dislocation dipole elements in a boundary element method approach and the plasticity was described by discrete dislocations. The crack was assumed to grow due to nucleation, glide and annihilation of dislocations along slip planes in the material in a single shear mechanism. The results of the investigation were compared to typical growth rates for long cracks and it was found that the increase in growth rate due to a prescribed stress intensity factor range was much less pronounced as compared to what holds for long cracks.

Crack Growth Rates for Short Fatigue Cracks Simulated Using a Discrete Dislocation Technique. P.Hansson: International Journal of Fatigue, 2009, 31[8-9], 1346-55