Feature Activated Molecular Dynamics: Parallelization and Application to Systems with Globally Varying Mechanical Fields

A recently developed hybrid molecular dynamics method (Feature Activated Molecular Dynamics, or FAMD), which was originally designed to extend the scope of certain types of molecular dynamics simulations, is extended here in two ways. First, the method is modified to execute on parallel computer architectures using the MPI communication interface. The parallel FAMD algorithm is demonstrated to be computationally efficient and to substantially increase the length scales accessible with molecular dynamics. The performance of the parallel algorithm is demonstrated using a crystalline system containing 1× 10⁶ atoms, in which 1000 supersaturated self-interstitials are introduced and allowed to aggregate for about 4 ns. In the second part of this paper, the FAMD method is applied to problems in which spatio-temporally varying stress fields are present throughout the simulation cell. In particular, we consider the evolution of a spherical void in a hydrostatically stressed silicon crystal and show that the method can capture the extremely rapid void cavitation dynamics following material failure. Once again, the FAMD approach is demonstrated to provide substantial computational advantages over standard molecular dynamics.