INVESTIGATION ON APPLICABILITY OF VARIOUS STRESS DEFINITIONS IN ATOMISTIC SIMULATION  

作　　者：Ran Xu Bin Liu 

机构地区：[1]AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China

出　　处：《Acta Mechanica Solida Sinica》2009年第6期644-649,共6页固体力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos10702034,10732050 and 90816006);the National Basic Research Program of China (973 Program 2007CB936803,2010CB832701)

摘　　要：How to correctly extract Cauchy stress from the atomistic simulations is a crucial issue in studying the mechanical behaviours of atomic systems, but is still in controversy. In this paper, three typical atomistic simulation examples are used to validate various existing stress definitions. It is found that the classical virial stress fails in predicting the stresses in these examples, because the velocity depends on the choice of the local average volume or the reference frame velocity and other factors. In contrast, the Lagrangian cross-section stress and Lagrangian virial stress are validated by these examples, and the instantaneous Lagrangian atomic stress definition is also proposed for dynamical problems.How to correctly extract Cauchy stress from the atomistic simulations is a crucial issue in studying the mechanical behaviours of atomic systems, but is still in controversy. In this paper, three typical atomistic simulation examples are used to validate various existing stress definitions. It is found that the classical virial stress fails in predicting the stresses in these examples, because the velocity depends on the choice of the local average volume or the reference frame velocity and other factors. In contrast, the Lagrangian cross-section stress and Lagrangian virial stress are validated by these examples, and the instantaneous Lagrangian atomic stress definition is also proposed for dynamical problems.

关 键 词：atomic stress virial stress atomistic simulation 

分 类 号：O344.3[理学—固体力学] TB383[理学—力学]