A modification to Hardy's thermomechanical theory that conserves fundamental properties more accurately

This work proposes a modification to Hardy's atomistic-to-continuum thermomechanical theory, so that it can more accurately conserve mass, momentum, and energy for non-equilibrium thermomechanical processes. The modification proposed is a new normalization rule for the localization function employed in the theory. The improved accuracy of the modified theory is demonstrated based on several molecular dynamics (MD) simulation examples of elastic and shock wave propagation in metals. Through the simulation results, it is also found that Hardy's theory remains valid to a large extent, regardless of the width of the localization function, the interatomic potential, and crystal structure, with and without ensemble averaging. The results from this work will help inject confidence in employing the modified Hardy's theory with the proposed modifications to analyze MD simulation results for non-equilibrium thermomechanical processes and pave the way for concurrent atomistic/continuum coupled simulations.