Vibration fatigue failure analysis and life prediction of high-speed turnout point rails

The degradation of rails web and rail foot, stemming from the propagation of cracks within the regions not directly impacted by contact stress from wheel-rail contact of turnout, has manifested as a typical fatigue in the railway infrastructure. Owing to the uncertainty regarding the main contributing factors and inadequate maintenance strategies, a comprehensive failure analysis and accurate life prediction are of pressing necessity. In this study, a novel transient wheel-rail rolling contact model incorporating explicit integration algorithms to investigate dynamic interactions in high-speed railway turnouts with pre-existing cracks is established. The model captures the temporal evolution of vertical and tangential contact force on crack surfaces within non-contact material zones of point rails during impact. Through integration of rain flow counting methodology and cumulative damage theory, the study predicts fatigue life while simultaneously observing microscopic crack propagation characteristics, the prediction of fatigue life is consistent with experiment results, the analytical results demonstrate significant speed-dependent interactions: increasing operational velocities amplify mutual constraint effects between crack surfaces, which will intensify contact forces and stress intensity factors (K_I/K_II) while reducing K_III, accelerating fatigue life degradation and driving dual-phase transgranular/intergranular crack propagation in rail substrates.