MOLECULAR DYNAMIC SIMULATION OF CRACK GROWTH.

Recent molecular dynamic simulations have shown that a 2D triangular Johnson (empirical iron potential) solid is brittle, compared with the behavior of a Lennard-Jones (L-J) solid. The crack velocity reaches a limiting velocity when the crack has grown by about 50 percent. The normalized (with respect to the longitudinal sound velocity) crack velocity vs the normalized (with respect to the initial length) crack length was found to be independent of the original crack length and the method of loading, indicating the absence of size effects. At high constant applied load, and hence high deformation, dislocation generation is observed with the crack completely stopped for a significant period of time.