横风环境下跨海大桥列车-桥梁系统耦合振动仿真研究

基于计算流体力学及弹性体在多体系统中的耦合理论,将计算流体力学、多体系统动力学及有限元结合起来,构建横风环境中列车-桥梁系统耦合振动的仿真平台,并以平潭海峡大小练岛水道斜拉桥为研究对象开展研究。列车-桥梁系统的气动模型构建采用局部动态层网格方法,计算列车-桥梁系统在不同风速和车速下的气动荷载。基于有限元方法和多体系统动力学方法建立列车-桥梁系统多体动力学模型,以时间激励方式施加气动荷载,仿真计算双线会车时不同风速和车速工况下列车-桥梁耦合系统的动力响应。研究结果表明:(1)随着风速的增大,桥梁主跨跨中竖向位移变化很小,而跨中横向位移显著增大,跨中竖向和横向振动加速度亦明显增大。风速和车速分别在30 m/s与300 km/h以内时,桥梁的挠度和振动加速度均能满足要求。(2)横风环境下列车在桥梁上运行时,头车的动力特性最为不利。随着风速和车速的增大,车辆的动力学指标均呈增大趋势。(3)列车行至桥梁跨中时轮重减载率出现最大值,两车交会时车体横向加速度发生突变且出现最大值,部分动力学指标不满足要求。(4)双线会车时,风速在10、20、30 m/s时的临界安全车速分别为296、256、147 km/h,临界舒适车速分别为166、150、106 km/h。

Simulation Study on Coupled Vibration of Train-bridge System of Cross-sea Bridge under Crosswind Condition

Taking the highway-railway steel truss cable-stayed bridge between the Dalian island and the Xiaolian island of the Pingtan Strait as the research object,the computational fluid dynamics,multi body system dynamics and finite element method were combined to establish the simulation platform of the train-bridge system coupled vibration in the crosswind condition based on the computational fluid dynamics theory and the coupled theory of flexible body in multi-body systems.By using the local dynamic layer grid,the aerodynamics simulation model of the train-bridge system was built to calculate the aerodynamic load of the train-bridge system under different wind speeds and vehicle speeds.Based on the finite element method and multi-body system dynamics method,the multi-body dynamics model of the train-bridge system was also built,and the aerodynamic loads were applied as time stimulations to the train and bridge.Then,the dynamic response of train-bridge coupling system was calculated when two trains passed by each other under the condition of different wind speeds and vehicle speeds.The research results show that:(1)with the increase of wind speed,the mid-span vertical displacement of the bridge changes little while the mid-span lateral displacement increases significantly,with the significant increase of the vertical and lateral vibration accelerations of the bridge.When wind speeds and vehicle speeds are within 30 m/s and 300 km/h respectively,both the deflections and vibration accelerations of the bridge can all meet the code requirements.(2)When the train passing the bridge under crosswind,the dynamic characteristics of the head train are in the most unfavorable condition.With the increase of wind speed and vehicle speed,the dynamics indexes of the train increase.(3)The maximum wheel load reduction rate appears when the train runs in the middle of the main span of the bridge.When the two trains meet,the maximum lateral acceleration of the vehicle body occurs due to its sudden change causing failure of part of the dynamic indexes to meet the requirements.(4)When the trains on the double track line meeting each other,the critical train safety speeds are 296 km/h,256 km/h and 147 km/h respectively and the critical comfort speeds are 166 km/h,150 km/h and 106 km/h respectively with the wind speeds at 10m/s,20m/s and 30m/s respectively.