Hunting stability analysis for high-speed trains under crosswinds

A 17-DOF mathematical model for a high-speed vehicle under steady crosswinds is established, and the nonlinear wheel/rail contact geometry and interactive forces are considered. Most importantly, the wheel profiles due to wears with the increase of operating mileage are measured, which have been used to calculate the wheel/rail contact geometry and equivalent conicity. The motion differential equation of the vehicle system is set up, and a program is written to calculate the critical speed under the corresponding parameters considering the vehicle running on straight and curved tracks with crosswind blowing to outer/inner rail. The linearization of the nonlinear vehicle system is conducted, and the critical speed is determined according to the eigenvalues of the linearized system in the equilibrium position. The results demonstrate that the critical speed of the vehicle system is significantly influenced by crosswind. The critical speed increases as the crosswind velocity is increasing when the crosswind blows to inner rail on curves, while it decreases as the crosswind blows to outer rail. And the wears of the wheel profiles also greatly contribute to the hunting stability of the vehicle system due to the resulted high equivalent conicity of wheel/rail contact. The critical speed increases with the increase of curve radius and super-elevation. It is also known through calculations that the derailment safety of the vehicle on curved track is greatly affected by crosswinds.