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基于曲线的最小二乘拟合方法,计算了Ti-6Al-4V绝热剪切带出现时的临界塑性剪切应变。根据梯度塑性理论,获得了绝热剪切带内部的局部塑性剪切变形分布曲线的理论表达式,用于拟合Liao及Duffy的实验数据。在不同的绝热剪切带宽度取值条件下,估算了绝热剪切带出现时的临界塑性剪切应变。当绝热剪切带的宽度取值在1~2mm时,计算出的临界塑性剪切应变在0.1~0.47之间。绝热剪切带内部的局部变形分布曲线的理论表达式可以很好地描述流线的非线性特征。当绝热剪切带的宽度取值较大时,绝热剪切带内部的流线的理论结果在两端较弯曲;而当其取值较小时,这些流线比较平直,仅稍微弯曲。
Based on the curve least squares fitting method, the critical plastic shear strain of Ti-6Al-4V adiabatic shear band was calculated. According to the gradient plasticity theory, the theoretical expression of the local plastic shear deformation distribution curve inside the adiabatic shear band is obtained, which is used to fit the experimental data of Liao and Duffy. Under different adiabatic shear band widths, the critical plastic shear strain of adiabatic shear bands is estimated. When the width of adiabatic shear band is between 1 and 2mm, the calculated critical plastic shear strain is between 0.1 and 0.47. The theoretical expression of the local deformation distribution curve inside the adiabatic shear band can well describe the nonlinear characteristics of the flow line. When the width of the adiabatic shear band is larger, the theoretical results of the flow lines inside the adiabatic shear band are more curved at both ends, whereas when the values are small, the flow lines are relatively straight and only slightly curved.