粘塑性
剪切矩阵
无定形固体
变形(气象学)
材料科学
蠕动
剪切(地质)
非晶态金属
压力(语言学)
本构方程
可塑性
经典力学
机械
物理
热力学
复合材料
有限元法
化学
语言学
哲学
有机化学
合金
作者
Michael L. Falk,J. S. Langer
出处
期刊:Physical review
日期:1998-06-01
卷期号:57 (6): 7192-7205
被引量:1812
标识
DOI:10.1103/physreve.57.7192
摘要
We propose a dynamical theory of low-temperature shear deformation in amorphous solids. Our analysis is based on molecular-dynamics simulations of a two-dimensional, two-component noncrystalline system. These numerical simulations reveal behavior typical of metallic glasses and other viscoplastic materials, specifically, reversible elastic deformation at small applied stresses, irreversible plastic deformation at larger stresses, a stress threshold above which unbounded plastic flow occurs, and a strong dependence of the state of the system on the history of past deformations. Microscopic observations suggest that a dynamically complete description of the macroscopic state of this deforming body requires specifying, in addition to stress and strain, certain average features of a population of two-state shear transformation zones. Our introduction of these new state variables into the constitutive equations for this system is an extension of earlier models of creep in metallic glasses. In the treatment presented here, we specialize to temperatures far below the glass transition, and postulate that irreversible motions are governed by local entropic fluctuations in the volumes of the transformation zones. In most respects, our theory is in good quantitative agreement with the rich variety of phenomena seen in the simulations.
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