A combined method of molecular dynamics with micromechanics improved by moving the molecular dynamics region successively in the simulation of elastic--plastic crack propagation

Molecular dynamics is applicable only for a small region of simulation. To simulate a large region it is necessary to combine molecular dynamics with continuum mechanics. Previously we proposed a new model in which molecular dynamics was combined with micromechanics. A molecular dynamics model was applied to the crack tip region and a micromechanics model to the surrounding region. In that model, however, crack propagation simulation must be stopped when the crack tip reaches the boundary of the two regions. In this paper the previous model is improved by moving the molecular dynamics region successively with crack propagation. The improved model may be applied to simulate limitless crack propagation. In order to examine the validity of the improved model, we simulate α-iron. The calculation cost with the improved model is less than a tenth of that of the previous model although the results are equal to each other. The crack tip opening displacement calculated with this model is almost equal to the analytical solution derived by Rice. This revised version was published online in July 2006 with corrections to the Cover Date.