Rolling Contact Fatigue Crack Initiation Prediction in Nose Rail of High-speed Railway Turnout Considering Plastic Deformation

Abstract:

According to the designed profiles of wing and nose rails at the No. 18 high-speed single-way turnout， the rolling contact fatigue （RCF） crack initiation in nose rail was predicted by the coexistence prediction method of RCF crack initiation and wear growth considering the impact load and material plastic deformation caused by the wheel load transfer from wing rail to nose rail when the train passes the turnout to side and reverse direction. The analysis shows that the worst position at the nose rail is the part with a top width of 35~40 mm at which the impact load caused by wheel load transferring is the largest. There would be plastic deformation at rail surface of this part under impact load which would reduce the material stress and strain obviously until the plastic deformation reaches a stable state with a certain number of wheel cycles. At that time， the maximum plastic deformation is 0.087 5~ 0.092 5 mm， which would prolong the （RCF） crack initiation. The maximum fatigue damage in the nose rail is at the rail subsurface. The RCF crack initiation positions for the nose rail at top width of 35 mm and 40 mm are 1.2 and 1.5 mm below rail surface vertically， 4~5 mm and 1~2 mm from rail center towards gauge side horizontally respectively. Moreover， the RCF crack initiation life are 1.63 ×10⁶ and 3.97 ×10⁶ tones at these two positions respectively.