高强双相钢动态力学及断裂失效行为表征

CHARACTERIZATION OF DYNAMIC MECHANICS AND FRACTURE-FAILURE BEHAVIOR OF HIGH-STRENGTH DUPLEX STEELS

先进高强钢的应用是实现汽车轻量化的重要途径之一,而材料力学性能断裂模型的精准表征能够有效提升整车碰撞安全仿真精度。以车身部件常用材料HC340/590DP钢作为研究对象,通过材料动态力学性能测试及本构方程拟合,描述了应变速率对HC340/590DP钢力学行为的影响,采用DIC+CAE技术,对静态拉伸、R5和R20缺口拉伸、中心孔拉伸、剪切拉伸以及拉剪拉伸6种典型应力状态下的断裂应变和应力三轴度进行测试分析,分析了该钢种的断裂形态,建立了HC340/590DP钢的断裂失效模型,并通过有限元对标计算和试样拉伸实测值的对比,验证了模型的准确性。结果表明:HC340/590DP钢具有明显的应变速率敏感性,随着应变速率的提高,材料的屈服强度和抗拉强度均随之增加;试验测得的不同应力状态下试样断裂模式及力-位移曲线均与数值仿真结果高度吻合,表明建立的材料模型适合用于工程仿真,能够对HC340/590DP钢在复杂应力状态下的断裂失效行为进行预测。

The application of advanced high-strength steel is one of the important ways to realize the lightweight of automobiles,and the accurate characterization of the fracture model of material mechanical properties can effectively improve the accuracy of vehicle collision safety simulation.Taking HC340/590DP steel,a commonly used material for body parts,as the research object,the influence of strain rate on the mechanical behavior of HC340/590DP steel was described through the dynamic mechanical properties test of the material and the fitting of constitutive equations.The fracture strain and stress triaxiality of the steel grade were analyzed by testing and analysis under six typical stress states of Shear stretching and tension-shear stretching,and the fracture failure model of HC340/590DP steel was established,and the accuracy of the model was verified by finite element benchmarking calculation and the comparison of the measured tensile values of the sample.The results show that HC340/590DP steel has obvious strain rate sensitivity,and the yield strength and tensile strength of the material increase with the increase of strain rate,and the fracture mode and force-displacement curve of the sample under different stress states are in good agreement with the numerical simulation results,indicating that the established material model is suitable for engineering simulation and can predict the fracture failure behavior of HC340/590DP steel under complex stress conditions.