强侧风下城际列车动力学性能分析

Dynamic performance analysis of intercity trains under strong crosswinds

为了分析国内某型城际动车组在明线平地25 m/s强侧风下非定常气动力对列车平稳性和安全性的影响,文章根据该型城际动车组实际外形和动力学参数,分别建立了8编组列车空气动力学和多体动力学模型。采用k-ωSST湍流模型计算了各节车所受的非定常气动力,将其作为外部激励输入到多体动力学模型中,形成流固耦合模型,计算了列车的风致车体振动及其安全性。结果表明,在定常强侧风下,各节车辆所受的气动力具有明显的非定常特性,其主频在0.5~7.0 Hz;在非定常气动力的作用下,各节车的横向和垂向平稳性指标均有所增大,其中头车的横向平稳性指标达到3.3,舒适度严重恶化;在较大的横向力和摇头力矩作用下,头车和尾车的车体与横向止挡发生碰撞是造成其横向振动加剧的原因;相较于无气动载荷,在25 m/s强侧风的条件下,列车头车和尾车的安全性指标明显增大,但仍保持在安全限度之内;增加横向止挡间隙、增大抗蛇行减振器和二系横向减振器的阻尼系数均可在一定程度上改善头车的风致横向振动。

This paper focused on analyzing the influence of unsteady aerodynamic forces on the stability and safety of a specific intercity electric multiple unit(EMU)model subjected to strong crosswinds of 25 m/s on level open tracks.Based on their actual geometric and dynamic parameters,aerodynamic and multi-body dynamic models were respectively established for the 8-car configuration.The k-ωSST turbulence model was used to calculate the unsteady aerodynamic forces acting on each car.These calculation results were then incorporated into the multi-body dynamic model as external excitations,leading to the development of a fluid-solid coupling simulation model for subsequent calculations related to wind-induced carbody vibrations and safety.The results showed that the aerodynamic forces acting on each car under steady strong crosswinds exhibited obvious unsteady behaviors,with main frequencies varying from 0.5 to 7.0 Hz.The influence of these unsteady aerodynamic forces led to an increase in both the lateral and vertical Sperling indexes of each car,with the lateral Sperling index of the head car reaching 3.3,indicating a considerable deterioration in ride comfort.The collisions between the bodies of the head and tail cars and the lateral stops,under the action of large lateral forces and yaw torques,exacerbated lateral vibrations.Compared with scenarios without aerodynamic loads,the safety indexes of both the head car and tail car under strong crosswinds of 25 m/s were significantly increased,but still remained within safety limits.The wind-induced lateral vibrations of the head car could be mitigated to some extent by increasing the lateral stop clearance and increasing the damping coefficient of both the anti-yaw damper and the secondary lateral damper.