40Mn钢高温高应变速率塑性本构行为

Plastic constitutive behavior of 40Mn steel at high temperatures andhigh strain rates

为研究40Mn钢在高温高应变速率下的塑性本构行为,利用分离式霍普金森压杆装置对40Mn钢开展了高温(650℃)和高应变速率(1700、2800、3500、4600和5500 s~(-1))下的压缩实验。实验结果显示,在应变速率高于4600 s~(-1)时,40Mn钢的应变速率强化效应明显减弱。对测量获得的应力和应变数据进行Johnson-Cook塑性本构模型拟合。利用MATLAB进行了材料塑性本构参数的优化,并在有限元模拟中应用了所构建的本构模型。通过对比有限元模拟和实验测量的高速压缩后的试样高度,验证了所构建本构模型及优化后的模型的预测精度。

To study the plastic constitutive behavior of 40Mn steel at high temperatures and high strain rates,the compression experiments of 40Mn steel at high temperature(650℃)and high strain rates(1700,2800,3500,4600 and 5500 s-1)were carried out using split Hopkinson pressure bar(SHPB)device.The experiment results show that the strain rate strengthening effect of 40Mn steel is obviously weakened when the strain rate is higher than 4600 s-1.The measured stress and strain data were fitted by Johnson-Cook plastic constitutive model.The plastic constitutive parameters of the material were optimized by MATLAB,and the constitutive model was applied in the finite element simulation.By comparing the sample height after high-speed compression measured by finite element simulation and experiment,the prediction accuracy of the constructed constitutive model and the optimized model was verified.