桥梁柔性对中低速磁浮车辆平曲线通过的影响

Influence of Bridge Flexibility on Horizontal Curve Passing of Medium-Low-Speed Maglev Vehicles

为研究桥梁柔性对中低速磁浮车辆在曲线半径为70.0 m的平曲线上运行时的动态响应影响,对通过柔性桥梁和刚性轨道时的车辆动态响应开展了对比分析.首先,建立了122个自由度的车辆空间动力学模型,模型中考虑了具有主动悬浮与被动导向特性的二维磁轨关系;其次,利用三维铁木辛柯梁参数化建模方法,建立了由柔性桥梁组成的平曲线有限元模型;最后,通过悬浮力的联系形成了车辆-曲线桥梁系统刚柔耦合动力学模型.研究结果表明:17.0 m跨径的圆曲线桥梁的自振特性和动位移响应满足相关标准要求;与车辆通过刚性轨道相比,柔性桥梁作用下的车辆系统动态响应更为剧烈,这种差异在车辆系统的横向动态响应上体现明显,而悬浮间隙和车体垂向加速度的响应差异较小,考虑刚性轨道时将高估车辆的曲线通过能力;柔性桥梁和刚性轨道两种模型计算得到的电磁铁最大横向位移不超过6.0 mm,悬浮间隙可在额定值的±4.0 mm内波动,表明在开展对比计算的工况下车辆具有良好的曲线通过性能.

In order to study the effect of bridge flexibility on the dynamic response of medium-low-speed maglev vehicles running on a horizontal curve with a curve radius of 70.0 m, a comparative analysis of the vehicle dynamic response through a flexible bridge and a rigid track is carried out. Firstly, a spatial dynamics vehicle model with 122 degrees of freedom is established, and the two-dimensional magnet/rail relationship with active levitation and passive guidance characteristics is considered in the model. Secondly, a horizontal curve finite element model consisting of flexible bridges is developed by using a parametric modeling method of threedimensional Timosheko beam. Finally, the rigid-flexible coupled dynamic model of the vehicle-curve bridge system is constructed with the connection of levitation forces. The results show that, the self-oscillation characteristics and dynamic displacement response of the 17.0 m span circular-curve bridge meet the requirements of relevant standards. Compared with the case of a vehicle passing the rigid track, the dynamic response of the vehicle system under the influence of the flexible bridge is more drastic, and evident in the lateral dynamic response of the vehicle system, while the difference in the response of the levitation gap and the vertical acceleration of the car body is smaller, and the curve passing ability of the vehicle will be overestimated in the case of the rigid track. The maximum lateral displacement of the electromagnet calculated with the flexible bridge and rigid track models does not exceed 6.0 mm, and the levitation gap fluctuates within ±4.0 mm of the rated value, indicating that the vehicle has a good curve passing performance in the comparison analysis.