Simulation of crack propagation with (molecular dynamics + micromechanics) model (3rd report, evaluation of fracture toughness and comparison with experimental results)

In this report the combined model of molecular dynamics with micromechanics was applied to a tungsten single crystal, and a crack propagation process was simulated till the material was fractured. In the simulation a pre-crack was introduced on a (110) plane and the direction was <001>. Cleavage, then, occurred along (121) plane which was in an inclined direction with respect to the pre-crack. The cleavage along (121) plane was also observed in an experiment. Three sizes of molecular dynamics regions were tested to investigate dependence of a simulation result on a size of a molecular dynamics region. It was found that the differences in the three simulation results were quite small. Fracture toughnesses in simulations, however, were about twice as large as that in an experiment.