Dynamic Response and Fatigue Analysis of Wheel/rail in the Weld Zone of High-speed Railway

Research purposes; Aiming at the problems of high-frequency vibration and wheel-rail impact damage of high-speed trains passing through the rail weld zone under different driving conditions, the vehicle-track coupling dynamic model is constructed by applying the train system dynamics theory, and the vertical dynamic response characteristics of typical irregularity of rail weld zone to wheel-rail and the possibility of fatigue damage are studied. Research conclusions: (1) The wheel-rail impact of high-speed train passing through concave weld is stronger than that of convex weld, and the vertical dynamic effect of wheel-rail passing through W-type irregularity is stronger than that of V-type irregularity. (2) With the increase of wave depth or the decrease of wavelength in the weld zone, the vertical response of wheel/rail is enhanced. In the actual line maintenance, it is recommended to use 0. 4 mm wave depth and 0. 4 m wavelength as the weld zone limit for grinding and maintenance. (3) Combined with the stability theory, the fatigue damage zone of the rail weld is determined. When the transverse displacement is greater than 9.5 mm, the fatigue factor is greater than zero. When the transverse displacement reaches 10. 1 mm, the fatigue factor of the convex weld zone reaches 0. 041, and the fatigue factor of the concave weld zone reaches 0. 068. The concave weld is more likely to produce fatigue cracks. (4) The research results can provide reference for the prediction of crack initiation possibility in high-speed railway weld zone and rail maintenance. © 2023 Editorial Department of Journal of Railway Engineering Society. All rights reserved.