分子动力学中应变分析的统计矩方法及应用

分子动力学模拟研究金属的力学性质, 需要采用合适的应变分析方法研究金属的变形特征及其演化规律. 金属材料复杂变形的局部应变特征缺乏简便有效的分析手段, 整体变形也没有合适的描述方法. 本文提出分子动力学中应变分析的统计矩方法, 通过统计矩建立了微观量和宏观应变的关联. 在单晶单轴加载、纳米多晶剪切和冲击加载下的应用表明, 矩应变分析方法可以很好的描述和评估材料的局部变形和整体变形特征, 并通过应变不均匀度鉴别材料的局部塑性变形和弹性变形, 是深入研究复杂结构材料变形机理的一种有效的通用分析方法.

Moment method for strain analysis and its application in molecular dynamics

It is necessary to investigate the characteristics and the evolution law of metal deformation by using the appropriate strain analysis method. The deformation of metal is complex, so there exists no useful method to amalyze the local deformation characteristics and to describe the global equivalent deformation of deformed metal. In this paper, we propose a statistical moment method of strain analysis. Statistical moment method builds up the relationship between micro quantities and macro strain. For instance, it is used to study the deformations of monocrystal under uniaxial load and the nanocrystalline under shear and shock, showing that moment method can not only describe and evaluate the local and the global deformation of metal but also distinguish elastic and plastic deformation by nonuniform coefficient. Moment method is a general and effective way to investigate the deformation mechanism of complex structure material.