一种高强度钢的动态力学本构参数识别和数值模拟

Identification of dynamic constitutive parameters of a high-strength steel and numerical simulation

分析了N-1钢在不同应变率条件下(10-3～103 s-1)的应力应变关系实验结果,得到了N-1钢的应变率强化特性。修正了平板试件断裂面中心的真实应力,并通过对真实应变与最小截面的厚度缩减率关系的研究,得到了断裂面中心的真实应变,从而识别出了N-1钢的修正Johnson-Cook本构模型的参数。利用所确定的本构关系模型,对N-1钢平板试件的杆-杆型冲击拉伸过程进行了数值模拟,模拟结果与实验结果较吻合,验证了采用的修正的Johnson-Cook本构模型参数的实验识别方法以及数值模拟方法的正确性。

The engineering stress-engineering strain relations of N-1 steel were measured using SHTB at different strain rates from 10-3 to 103 s-1.The results were analyzed,and the rate-hardening law of N-1 steel was determined.The true stress at the center of the fractured cross-section was calculated.The relation between true strain and specimen's varying thickness within the smallest cross-section was explored,and the true strain at the center of the fractured cross-section was identified with a modified approach.Thus the modified Johnson-Cook(MJC) constitutive model parameters of N-1 steel were identified.The bar-bar impact tensile experiments with rectangular cross-section specimens were numerically simulated to verify the proposed constitutive model parameter identification method and simulation method.The simulated results are satisfying.