Abstract: 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.

Key words: DIEM failure model, SUS301L-MT, stress state, element size dependence