A Concurrent Atomistic Continuum Method on LAMMPS

Predicting the properties and dynamic behavior of materials with mesoscale structural features is a significant challenge. This talk presents a massively parallel concurrent multiscale method that aims to address this challenge. The multiscale method is based on a Concurrent Atomistic-Continuum (CAC) formulation of conservation laws, which is an extension of Irving-Kirkwood's statistical formulation of transport processes, and has a parallel implementation on the LAMMPS codebase. By using a modified finite element representation for crystalline regions, including regions with lattice defects such as dislocations and cracks, the CAC method enables the predictive simulation of time dependent responses for materials with mesoscale hierarchies. With a significantly reduced computational cost, the tool promises comparable predictive power to MD (Molecular Dynamics) for the simulation and visualization of dynamically coupled mechanical and phonon transport behavior in mesoscale microstructures with no empirical rules or parameters other than an interatomic potential. The methodology has been verified by comparing CAC and atomically resolved MD simulation results of phonon propagation in silicon, phonon scattering by microstructures, and the nucleation and propagation of defects.