悬挂式单轨双线曲线轨道梁的设计研究

Research on the Design of Suspended Monorail Double Curved Track Beams

悬挂式单轨的轨道梁既是承重结构,又兼作车辆的走行和导向轨道。为保证列车运行的安全性和舒适性,车辆系统对轨道梁在列车荷载作用下的变形有严格的要求。由于轨道梁为底部开口的薄壁钢结构,抗扭刚度较小,导致曲线轨道梁适用跨径较小,给工程建设带来困难。提出在左右线轨道梁之间设置横梁的结构方案,增加轨道梁的整体刚度,有效减小曲线轨道梁的弯扭变形。为验证设计方案,对横梁的截面形式、设置间距、横梁连接构造等进行计算分析和对比。采用壳单元建立分析模型,针对列车静活载工况进行有限元分析。计算结果表明,当半径为60 m时,采用横梁结构设计可将简支曲线轨道梁适用跨径从16.5 m提高到23 m。横梁采用箱形截面与工字形截面相比,竖向位移减小约14%。此外,轨道梁与横梁连接处设置过渡段可明显降低应力集中,使结构受力均匀。综合考虑受力、经济性等因素,建议曲线轨道梁跨径20 m左右时,设置2道横梁。研究表明,本文提出的横梁结构可大幅增加曲线轨道梁的适用跨径,提高列车运行的安全性和乘坐舒适性。

The track beam of suspended monorail is not only a load-bearing structure,but also a running and guiding track for vehicles.In order to ensure the safety and comfort of train operation,the deformation of track beam under train loads in vehicle system is strictly limited.Because the track beam is a thin-walled steel structure with an opening at the bottom,its small torsional rigidity leads to a small applicable span of the curved track beam and brings difficulties to the engineering construction.In this paper,a scheme of setting crossbeams between two track beams is proposed to increase the overall rigidity of the track beams and effectively reduce the bending and torsional deformation of the curved track beams.In order to verify the design scheme,the section form,spacing and connection structure of the crossbeam are calculated,analyzed and compared.The shell element is used to establish analytical model and conduct finite element analysis of the static and live load conditions of the system.The calculation results show that when the radius is 60 m,the applicable span of simply supported curved track beam can be increased from 16.5 m to 23 m by adopting the crossbeam structure design.The vertical displacement of crossbeam with box section decreases about 14%compared with I-section.In addition,the transition section set up at the joint between the track beam and the crossbeam can obviously reduce the stress concentration and contribute even structure stress.Comprehensively considering the factors of mechanical properties of the structure and economy,it is suggested that two crossbeams should be set for the curved track beam with a span of about 20 m.The research shows that the curved rail beam structure proposed in this paper can greatly increase the applicable span of the rail beam,and improve the stability and comfort of train operation.