基于Gissmo失效准则的DP590双相钢和热成形钢的断裂特性研究

Research on fracture characteristics of DP590 double-phase steel and hot-formed steel based on Gissmo failure criterion

首先对车身上常用的DP590双相钢和热成形钢进行了6种不同应力三轴度下的试验研究,获取了材料的基本力学特性。使用Ludwike硬化模型获取了材料颈缩后的真实塑性应力-真实塑性应变曲线,并通过对比颈缩较小的纯剪切工况仿真模拟结果与试验结果验证了外插曲线的正确性。通过仿真逆向优化的方式,使用LS-OPT软件获取了可以描述材料非线性损伤的Gissmo失效模型参数。为快速准确地获取模型参数,提出了一种获取待优化参数初始值并采用不同应力三轴度区间开展模型系数优化的方法。最后,开展了未参与优化的60°拉剪和R 6缺口工况的仿真模拟,仿真结果与试验结果一致,从而验证了模型参数的正确性。

The experimental researches on DP590 double-phase steel and hot-formed steel commonly used for car body with six kinds of stress triaxialities were carried out,and the basic mechanical properties of materials were obtained.The Ludwike hardening model was used to obtain the true plastic stress-true plastic strain curves of materials after necking,and the accuracy of external interlude curves was verified by comparing the simulation results of the pure shear working condition with smaller necking and the experimental results.The Gissmo failure model parameters that can describe nonlinear damage of materials were obtained by using LS-OPT software through simulation reverse optimization.In order to obtain the model parameters quickly and accurately,a method of obtaining the initial values of the parameters to be optimized and carrying out the model coefficients optimization with different stress triaxial intervals was proposed.Finally,the simulation of 60°tensile-shear and R 6 notch working conditions without participating in the optimization was carried out,and the simulation results are in good agreement with the experimental results,thus the accuracy of the model parameters is verified.