Contemporary time integration model of atomic systems using a dynamic framework of finite element Lagrangian mechanics

摘要

Molecular dynamics simulations are essential tools to understand the equilibrium and non-equilibrium behaviour of atomistic structures under the context of classical mechanics. A major disadvantage of such results is that it conventionally encompasses small simulation times ensuing from a high demand in computational power. Certain transport properties can be obtained from such computational simulations only when allowing large enough runtime to observe the kinetic behaviour while considering multiple mechanical conditions such as low strain rates and low cycle fatigues. In this study, we developed a dynamic framework for atomic modeling using finite element Lagrangian mechanics. The method is proposed to obtain thermo-dynamical properties under microcanonical ensembles. We compare the current work with two conventional time integration approaches. It was found that the method has been able to achieve more than 5 times the time step possible for the two chosen methods in strain-loading analyses. The method had much higher numerical stability than conventional approaches, with a larger step size convergence than previously reported for future implementation in an explicit/implicit numerical integration. (C) 2017 Elsevier Ltd. All rights reserved.