具有初始随机材料缺陷的非晶合金剪切带模拟

基于自由体积理论建立了以自由体积为内部参量的非晶合金本构模型,并通过ABAQUS UMAT子程序将之在有限元模拟中实现.以初始自由体积为材料缺陷参量,通过FORTRAN子程序抽取随机数及匹配单元编号的方法定义了初始随机材料缺陷.采用平面应变模型模拟了具有初始随机材料缺陷的非晶合金剪切带的形成和扩展过程,结果表明:自由体积局部增加会造成形变局部化,继而形成剪切带,并且剪切带的成核、形成和扩展会松弛周围应变和自由体积.数值模拟能有效捕捉非晶合金剪切带主要特征,其结果符合实验观察和自由体积理论预测.

Numerical simulation of shear band in amorphous alloy with initially random material imperfections

Based on the free volume theory,a constitutive model of amorphous alloy with free volume as an internal variable was developed to be implemented in the finite element simulation by ABAQUS UMAT subroutine.The initial free volume was taken as the variable of material imperfections.And the initial random material imperfections were defined through extracting random numbers and matching them with element numbering by a FORTRAN program.A plane strain model was utilized to simulate the formation and propagation of shear band in amorphous alloy with initial random material imperfections.It was found that local increase in free volume could induce localized deformation and the subsequent formation of shear band.The nucleation,formation and propagation of shear band could relax the strain and free volume in its surroundings.The simulation could capture the main feature of shear band in amorphous alloy.The results coincide with the experimental observation and the predictions of free volume theory.