车用双相高强钢的动态力学性能及本构模型的对比

Dynamic Mechanical Properties and Constitutive Model Contrast of Dual-Phase High Strength Steel for Vehicles

通过不同应变速率(0.001~500 s^(-1))下的室温拉伸试验,研究了车用HC340/590DP、HC700/980DP双相高强钢的动态力学性能;分别采用Johnson-Cook模型、Swift-Hockett/Sherby模型,以及将Swift-Hockett/Sherby模型引入到Ludwik模型中的修正模型对2种钢的流动应力-应变曲线进行拟合,对比分析3种本构模型的拟合结果。结果表明:随着应变速率的增加,2种钢均表现出增强增塑现象;Johnson-Cook模型、Swift-Hockett/Sherby模型和修正Ludwik模型的拟合度平均值分别为0.950,0.999,0.997;修正Ludwik模型既具有各应变速率间应力耦合的特点,又保持了高拟合精度,可以准确描述车用双相高强钢的动态流变行为。

The dynamic mechanical properties of dual-phase high strength steels HC340/590DP and HC700/980DP for vehicles were studied by room temperature tensile tests at different strain rates(0.001-500 s^(-1)).The flow stress-strain curves of the two steels were fitted by Johnson-Cook model,Swift Hockett/Sherby model and the modified model obtained by introducing Swift Hockett/Sherby model into Ludwik model,and the fitting results of the three constitutive models were compared and analyzed.The results show that with increasing strain rate,two steels both exhibited the phenomenon of strengthening and plasticizing.The average fit values of Johnson-Cook model,Swift Hockett/Sherby model,and modified Ludwik model were 0.950,0.999,0.997,respectively.The modified Ludwik model not only had the coupling characteristics of stress at each strain rate,but also maintained the high fitting accuracy;it could accurately describe the dynamic rheological behaviors of dual-phase high strength steels for vehicles.