Mechanism of High-Speed Train Crosswind Overturning Stability Based on Frequency Domain Analysis

The dominant factor impacting the dynamic performance of a train under a crosswind changes from wheel-rail interactions to the aerodynamic force, making the crosswind overturning risk the main threat to safe train operation. This study first analyzes the train overturning stability using a refined coupling model to reveal its sensitivity to the train model. On the basis of a frequency domain framework accounting for the modal characteristic, transfer functions between the wind turbulence and track irregularities and the overturning responses are derived. The mechanism of train crosswind overturning is then intuitively interpreted via a parameter analysis. The results show that the overturning behavior of a train is controlled by the rolling mode around the lower center of the car body and the floating mode of the car body and that the influence of the wind load is significantly greater than that of track irregularities. Under track irregularity excitation, the first modal response primarily arises from the alignment component, while the second modal response arises from the vertical component. Under a wind load, the longitudinal fluctuating wind component plays a major role. Increasing the train speed, wind velocity, and wind direction angle increases the dynamic response of the train and reduces the maximum allowable wind speed to safely run the train. An increase in the failure probability can reduce extreme responses and increase the wind speed for safe operation.