Main Crack Propagation Behavior of U71Mn Steel Considering Secondary Crack

Using the finite element software ANSYS and combining the fatigue and wear coupling model, the equivalent stress intensity factors of cracks were simulated and calculated when the 10-ton wheel rolled over on the rail surface crack that had an initial length of 100 μm and an extension angle of 30°. The relationship between rail fatigue and wear was investigated and the propagation directions of the main and secondary cracks and the propagation behavior of main cracks after the secondary cracks appearing were also analyzed. The results show that the destruction mode of the rail gave priority to fatigue damage. When the branched cracks appeared, the stress concentration at the main crack tip would be relatively largely relieved, resulting in a relatively rapid decrease of the equivalent stress intensity factor. After the crack propagation length reached over 1 mm, the main crack further propagation process was accompanied by the appearance of secondary cracks; the propagation direction of the main crack remained unchanged and the propagation rate increased gradually, while the propagation directions and rates of the secondary cracks remained unchanged.