SUS301L-MT不锈钢失效行为表征

Characterization of Failure Behaviour of SUS301L-MT Stainless Steel

为更好地表征轨道列车碰撞过程中不锈钢结构的断裂失效行为,开展了常用SUS301L-MT材料的断裂失效行为研究。首先,进行不同应变率下的单轴拉伸试验和不同应力状态下的准静态断裂试验;然后,通过对断裂试验试件的有限元仿真,利用有限元逆向识别优化法进行了损伤起始与演化的参数识别,得到试件的仿真与试验的力-位移曲线均方差最大值为6.947%,断裂处应变误差最大值为9.551%,仿真与试验的断裂形态基本一致;在此基础上,建立SUS301L-MT不锈钢的损伤起始与演化失效模型(Damage initiation and evolution failure model,DIEM),通过试验和仿真分析,验证了DIEM失效模型的有效性;最后,为解决该模型的单元尺寸依赖性,通过对不同尺寸单元的有限元模型进行分析,提出DIEM失效模型的单元尺寸修正系数。结果表明,建立的失效模型能够准确表征SUS301L-MT不锈钢的失效行为,修正系数的引入可有效改善该失效模型的单元尺寸依赖性。

In order to better characterize the fracture failure behaviour of the stainless steel structure in the process of rail train collision,the fracture failure behaviour of commonly used SUS301L-MT material was studied.Firstly,uniaxial tensile tests under different strain rates and quasi-static fracture tests under different stress states were carried out.Then,by means of finite element simulation of fracture test specimen,the parameters of damage initiation and evolution were identified by the finite element inverse identification optimization method.The maximum mean square error of the force-displacement curve obtained by the method is 6.947%,and the maximum strain error at the fracture is 9.551%.The fracture morphology of the simulation and the test are basically the same.On this basis,the damage initiation and evolution failure model(DIEM)of SUS301L-MT stainless steel was established.The effectiveness of the DIEM failure model was verified by experiments and simulation analysis.Finally,in order to solve the element size dependence of the model,the element size correction factor of the DIEM failure model was proposed by analyzing the finite element models with different dimensions.The results show that the established failure model can accurately characterize the failure behaviour of SUS301L-MT stainless steel,and the introduction of correction factor can effectively improve the element size dependence of the failure model.