Simulation of crack propagation with (molecular dynamics+micromechanics) model (2nd report, proposal of an advanced model)

Molecular dynamics is applicable for only a small region of simulation. To simulate a large region, it is necessary to combine molecular dynamics with continuum mechanics. In the first report, we proposed a new model in which molecular dynamics was combined with micromechanics. Namely, we applied a molecular dynamics model to the crack tip region and a micromechanics model to the surrounding region, respectively. In this model, however, crack propagation simulation must be stopped when the crack tip reaches to the boundary of the two regions after the crack propagation. Therefore, in this paper, we improve the previous model by allowing the movement of the molecular dynamics region. Theoretically, the process of the crack propagation can be simulated endlessly with this advanced mo.del. In order to examine the validity of the advanced model, we use a-iron in simulation. It is found that the result based on this advanced model is equal to the result with the previous model. Moreover, the result is almost equal to the Rice's solution.