Load characteristics analysis of the high-speed turnout rail bottom under random factors

• A refined vehicle-frog dynamic interaction analysis model is established. • The factors significantly influencing the multi-axial vibration fatigue are identified. • The statistical characteristics of the rail load and rail bottom stress are analysed. • A mapping relationship between the load and rail bottom stress is established. The fatigue damage occurring at the rail bottom is one of the most common forms of damage observed in high-speed turnout. The dynamic mechanical behaviour of the wheel-rail system and the mechanical properties of the rail material are key factors influencing this fatigue damage. In this paper, a refined high-speed vehicle-frog dynamic interaction analysis model, which takes into account the material properties and complex constraints, was developed. The unreplicated saturated factorial design method was used to identify factors significantly influencing the multi-axial vibration fatigue of the frog. The time domain and frequency domain statistical characteristics of the rail load and rail bottom stress in the frog were then analysed. Additionally, the Gaussianity and stationarity of the random load in the frog were assessed. Using non-parametric kernel density estimation, the load was extrapolated, and a full life cycle load spectrum for the frog rail was developed. Finally, a mapping relationship between the load and rail bottom stress was established.