基于频域分析的高速列车侧风倾覆机理

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

侧风作用下列车的动态环境以轮轨相互作用为主向,以空气动力作用为主演变,列车的侧风倾覆行为成为威胁列车行车安全性的主要诱因.首先,采用精细化车-轨耦合模型开展列车侧风倾覆的频域特性分析,以明确侧风倾覆响应对列车模型的敏感性;基于考虑模态特性的频域分析框架,推导脉动风及轨道不平顺与列车倾覆动力响应间的传递函数,结合相应参数进行分析,以直观揭示列车的侧风倾覆机理.结果表明:列车倾覆行为受绕车体下心侧滚模态和车体沉浮模态控制影响,其风荷载影响要明显大于轨道不平顺;在轨道不平顺激励下,第一阶模态贡献主要由轨向不平顺引起,第二阶模态贡献主要由高低不平顺引起,在脉动风荷载激励下,其顺风向脉动风分量起主要贡献;车速、风速和风向角的增大都会引起列车动力响应的增大,进而降低列车安全运营时的最大允许风速;失效概率的增大会降低动力响应的极值,进而提高安全运营风速.

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.