An overview of molecular dynamics simulations of plasticity in solids at experimentally relevant timescales
Received:January 17, 2021  Revised:February 27, 2021
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DOI:10.7511/jslx20210117002
KeyWord:molecular dynamics  accelerated molecular dynamics  plasticity of solid  time scale
  
AuthorInstitution
王云江 中国科学院力学研究所 非线性力学国家重点实验室, 北京 ;中国科学院大学 工程科学学院, 北京
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Abstract:
      Molecular dynamics (MD) simulations based on an empirical force field has played a critical role in analysis of the microscopic plastic mechanisms of versatile solids,in light of the great advances in both software and hardware of supercomputers.However,a classical MD is conducted by taking time integration of the Newtonian equation of motion with a very tiny timestep of the order of femtosecond.Therefore,a typical MD simulation of million steps can only explore a timescale window of nanosecond,which brings about a great challenge in long timescale simulations,e. g.,of plastic deformation of solids.This paper will start with a brief introduction of the timescale issue in MD.Then,several state-of-the-art accelerated MD techniques are introduced which are capable of performing atomistic simulations up to experimentally relevant timescales.Several examples including dislocation plasticity in crystalline metals,as well as diffusion and shear transformation in amorphous materials will be computed in detail to demonstrate the basic ideas and procedures of atomic-scale simulations at experimental timescale.Finally,common shortcomings of modern accelerated molecular dynamics techniques,and possible solutions for a final goal of MD simulations spanning the whole timescale domain of plasticity in solid are discussed.