The crack growth which was associated with plane-strain mode-I loading was studied by using discrete-dislocation and non-local crystal plasticity methods. In the discrete-dislocation approach, the material was modelled as a linear elastic solid which contained discrete dislocations that were capable of moving and interacting with each other and with other lattice defects; either at a distance via their stress fields, or by direct contact. In the case of non-local crystal plasticity, the effect of the plastic strain gradient upon material behavior was incorporated via the contribution that geometrically necessary dislocations made to the rate of strain hardening. In both methods, the behavior of the crack was modelled by using a cohesive zone approach. The results showed that both approaches yielded comparable stress and strain fields around the crack tip, but that the

global (stress intensity versus crack extension) responses as well as the crack-tip profiles could be significantly different in the two cases. These differences were related to the way in which crystallographic slip was modelled in the 2 approaches.

A Comparative Discrete-Dislocation/Non-Local Crystal-Plasticity Analysis of Plane-Strain Mode-I Fracture. D.Columbus, M.Grujicic: Materials Science and Engineering A, 2002, 323[1-2], 386-402