基于GISSMO失效准则的1500 MPa热成形钢断裂失效模型分析

Fracture failure model analysis of 1500 MPa hot forming steel based on GISSMO failure criterion

以CR1000/1500HS为研究对象,基于GISSMO断裂失效准则,设计表征不同失效形式的5种测试试样;基于万能拉伸试验机和DIC测试系统,获取不同试样拉伸过程的力-位移曲线和断裂时刻的极限塑性应变;基于LS-DYNA搭建各失效试样的仿真分析模型,提取各试样断裂区域的应力三轴度;拟合获得断裂失效曲线和塑性失稳曲线,迭代获取其他模型参数;采用车门防撞梁动态三点弯曲冲击试验和仿真模型对承载特性进行分析;对比GISSMO失效模型、传统应变失效模型与试验测试的力-位移曲线差异,以验证失效模型的准确性。结果表明:Swift和Hockett-Sherby混合硬化模型可准确描述材料的塑性变形行为,关键参数误差小于5%;GISSMO失效模型获得的车门防撞梁承载特性关键参数和承载力-位移曲线与试验测试结果保持一致,误差低于5%;而采用传统应变失效准则获得的结果误差较大,最大位移的误差达到30%;表明基于GISSMO失效准则的材料模型可以准确表征CR1000/1500HS的塑性变形行为及断裂失效行为。

Taking CR1000/1500HS as the research object,based on the GISSMO fracture failure criterion,five kinds of test samples were designed to characterize different failure modes.Based on the universal tensile testing machine and DIC test system,the force-displacement curves and the ultimate plastic strain at the fracture time of different samples during tensile process were obtained.Based on LS-DYNA,the simulation analysis model of each failure sample was built,and the stress triaxiality of the fracture area of each sample was extracted.The fracture failure curves and plastic instability curves were obtained by fitting,and other model parameters were obtained by iteration.The dynamic three-point bending impact test and simulation model of the car door anti-collision beam were used to analyze the bearing characteristics.The difference of force-displacement curves between the GISSMO failure model,the traditional strain failure model and the test was compared to verify the accuracy of the failure model.The results show that the Swift and Hockett-Sherby mixed hardening model can accurately describe the plastic deformation behavior of the material,and the error of the key parameters is less than 5%.The key parameters of the bearing characteristics and the bearing capacity-displacement curves of the car door anti-collision beam which obtained by the GISSMO failure model are consistent with the test results,and the error is less than 5%.The error of the results obtained by the traditional strain failure criterion is large,and the error of the maximum displacement reaches 30%.It indicates that the material model based on GISSMO failure criterion can accurately characterize the plastic deformation behavior and fracture failure behavior of CR1000/1500HS.