45钢绝热剪切变形数值模拟

Numerical Simulation of Adiabatic Shearing Deformation for 45 Steel

采用Ansys/Lsdyna对SHPB加载条件下不同热处理状态的45钢进行了2D数值模拟,数值重现了帽型试样高应变条件下的绝热剪切变形历程。计算中采用二维轴对称应变条件下的两种网格模型,材料本构方程采用热粘塑性Johnson-Cook本构关系,基于应力塌陷绝热剪切形成判据和等效应力-时间曲线分析了绝热剪切变形规律。计算结果表明,绝热剪切敏感性与加载速率和材料的组织结构密切相关。

The adiabatic shearing deformation of hat-shaped 45 steel specimens with different heat-treated conditions under high strain rate by means of SHPB was analyzed by the method of 2D Ansys/Lsdyna numerical simulation. Based on the crite- rion that the formation of adiabatic shear corresponds to Stress Collage and the equivalent stress - strain curves, the 2D axisymmetric mesh mode and Johnson-Cook constitutive relation of thermoviscoplasticity were used to investigate the adiabatic shearing deformation. The results of numeration show that adiabatic shearing sensitivity is influenced by loading rate and structure of 45 steel.