中低速磁浮车辆-轨道-桥梁垂向耦合振动仿真分析

以长沙中低速磁浮列车和25 m跨径简支梁为对象,建立包含完整悬浮控制系统和细致轨道结构的磁浮车辆-轨道-桥梁垂向耦合振动模型,编制数值仿真程序,计算车辆以80 km/h速度通过不平顺线路时车轨桥耦合动力学响应,利用已有文献测试结果初步验证仿真模型。结果表明,车体的垂向振动很小,悬浮间隙波动量不超过0. 6 mm,最大动态悬浮力占额定悬浮力的24%,中低速磁浮车辆运行平稳,电磁铁动荷载系数低。桥梁跨中垂向挠度为2. 66 mm,小于磁浮简支梁挠跨比设计限值;跨中轨缝处F轨最大垂向位移为3. 04 mm,其中包含轨排自身弹性变形产生的0. 4 mm垂向位移,约占F轨总位移的13%。梁端和跨中处伸缩接头很好地限制F轨端部变形,但F轨端部垂向加速度幅值超过2g,约为中部的4倍,这对F轨伸缩缝连接副提出较高要求。

Numerical Analysis on Vertical Coupled Vibration of Medium-low Speed Maglev Vehicle-Track-Viaduct System

A detailed vertical dynamic model of maglev vehicle-track-girder coupled system is built with reference to the medium-low speed maglev train and the 25 m-span girder for Changsha Maglev Express.The model is consisted of an integrated electromagnetic levitation control system and detailed track structures,and corresponding numerical analysis program is developed. Then,dynamic responses of maglev vehicle-track-girder coupled system are calculated when the vehicle runs on irregularity tracks at the speed of 80 km/h,and numerical results are compared with test results in existing literatures so as to validate preliminarily the dynamic model. Numerical results show that the vertical acceleration of carbody is quite small,the fluctuating levitation airgap of electromagnet is less than 0. 6 mm,and the maximum dynamic electromagnetic force accounts for about 24% of nominal levitation force,which indicates that the ride quality of medium-low speed maglev vehicle is excellent and the dynamic load factor of electromagnet is low. The vertical mid-span displacement of girder is 2. 66 mm,which is less than the allowed deflection limit for maglev simply supported girder. The maximum vertical displacement of F-shaped rail located at the mid-span reaches 3. 04 mm,including 0. 4 mm vertical deformation of track panel and coveringabout 13% of the total vertical displacement. The I-type expansion joint can control effectively the deformation of both ends of F-shaped rail,but the vertical acceleration of F-shaped rail end is greater than 2g,which is about 4 times of that of the middle part,exerting high requirement on expansion joint connectors.