The conditions for dislocation emission from a crack tip, as well as crack propagation under mode-I conditions, were analyzed by using the Rice model (based upon the Peierls-Nabarro framework) and a molecular dynamics technique which included virial stresses. The atomistic results which were obtained by using a pair potential agreed satisfactorily with the continuum prediction with regard to the loading conditions for dislocation emission. Crack extension was observed in atomistic simulations when the normal virial stress at the crack tip exceeded the cohesive strength of the potential.

Stability of the Crack Tip in Terms of Molecular Dynamics. A.Machova, G.E.Beltz: Metallic Materials, 1998, 36[3], 97-102