Hunting stability analysis for high-speed trains under crosswinds
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Hunting stability analysis for high‑speed trains under crosswinds Ran‑cheng Mao1 · Jing Zeng1 Received: 23 November 2019 / Accepted: 26 March 2020 © Springer Nature Switzerland AG 2020
Abstract 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. Keywords High-speed vehicle · Crosswinds · Critical speed · Stability · Derailment safety
1 Introduction The stability of railway vehicles is a considerable issue that is decisive to the maximum operating speed for trains running on tracks and it is regarded as an essential index in the assessment of vehicle dynamic behavior. Instability must be prevented in any operation condition, otherwise serious hunting oscillation will occur, which can be extremely detrimental to the operation safety [1]. Meanwhile, regarding the discrepancy of the hunting stability on straight line and curved track, respective studies should be launched with the consideration of their own features. The hunting motion of railway vehicles is closely related to the nonlinear wheel/rail interactive forces, centrifugal forces and crosswind loads on curved tracks, which will determine the equilibrium position of vehicle system
during curve negotiation [2]. However, with the continuous increase of train speed, the effects of crosswinds on vehicle stability are gradually obvious, requiring more awareness on the aspects of aerodynamic forces [3]. In the past decades, numerous studies had been carried out by researchers with respect to the hunting stability of railway vehicles. Through linearizing the nonlinear dynamic equations of vehicle system at the equilibrium position, and determin
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