Parallel molecular dynamics simulations, involving up to 35 million atoms, were performed in order to investigate dislocation emission from a three-dimensional crack. Dislocation loop emission from the crack front, both in the bulk and near to the free surface, was observed. The sequence of dislocation emission during crack blunting depended strongly upon the crystallographic orientation of the crack front, and differed markedly from any process which had previously been proposed. This discovery was invaluable for the establishment of precise dislocation emission criteria. It was also found that boundary conditions and interatomic force laws had a significant effect upon jogging or blunting of dislocation emission modes.

Three-Dimensional Fracture via Large-Scale Molecular Dynamics. S.J.Zhou, P.S.Lomdahl, A.F.Voter, B.L.Holian: Engineering Fracture Mechanics, 1998, 61[1], 173-87