A Hybrid Molecular Dynamics/Atomic Scale Finite Element Method for Quasi Static Atomistic Simulations at Finite Temperature

Abstract

In this paper, a hybrid quasistatic atomistic simulation method at finite temperature is developed, which combines the advantages of MD for thermal equilibrium and atomicscale finite element method (AFEM) for efficient equilibration. Some temperature effects are embedded in static AFEM simulation by applying the virtual and equivalent thermal disturbance forces extracted from MD. Alternatively performing MD and AFEM can quickly obtain a series of thermodynamic equilibrium configurations such that a quasistatic process is modeled. Moreover, a stirringaccelerated MD/AFEM fast relaxation approach is proposed in which the atomic forces and velocities are randomly exchanged to artificially accelerate the “slow processesâ€‌ such as mechanical wave propagation and thermal diffusion. The efficiency of the proposed methods is demonstrated by numerical examples on single wall carbon nanotubes.