The propagation of short cracks in the neighborhood of grain boundaries was investigated by using a technique in which the crack was modelled by distributed dislocation dipoles, and the plastic deformation was represented by discrete dislocations. Discrete dislocations were emitted from the crack tip as the crack grew. Dislocations could also nucleate at the grain boundaries. The influence of the distance, between the initial crack tip and the grain boundary, upon the crack-growth characteristics was studied. It was found that the crack growth rate was strongly related to dislocation pile-ups at the grain boundaries.

A Study of the Influence of Grain Boundaries on Short Crack Growth during Varying Load using a Dislocation Technique. C.Bjerkén, S.Melin: Engineering Fracture Mechanics, 2004, 71[15], 2215-27