【摘要】 中低速磁浮交通作为一种新兴的交通方式,其轨道结构形式与传统轮轨交通的轨道有较大的区别。为了研究中低速磁浮交通线路中轨道-桥梁系统竖向振动特性,基于某中低速磁浮试验线,以20 m预应力混凝土简支梁为研究对象,建立轨道-桥梁系统竖向振动传递有限元模型并进行振动传递特性分析,随后探讨了激励位置,扣件竖向刚度,轨枕间距对系统竖向振动传递特性的影响。研究表明:系统的位移导纳存在两个峰值,频率分别对应为系统的整体一阶竖弯和F轨的局部一阶竖弯;随着考察点与荷载激励点距离的增大,在F轨局部一阶竖弯频率之后,F轨的位移导纳幅值变化不显著;激励位于扣件处时,在100～200 Hz F轨的位移导纳振动幅值要大于激励位于非扣件处时;扣件刚度和轨枕间距均会影响轨道结构的局部刚度,从而影响F轨的局部一阶竖弯频率值和在此频率点处的F轨位移导纳幅值;F轨的局部变形较明显,建议在后续的时域磁浮车桥耦合振动模型中应考虑F轨的影响。更多还原

【Abstract】 As a new mode of traffic, the track structure form of the medium-low speed maglev traffics is different from that of traditional wheel-rail traffics. In order to study its vertical vibration characteristics, based on a medium-low speed maglev test line, a twenty-meter prestressed concrete simply supported beam was taken as the research object. The finite element model for the vertical vibration transmission of the rail-bridge system was established and the vibration transmission characteristics were analyzed. Then, the influence of force location, vertical fastener stiffness and sleeper pitch on vertical vibration transmission characteristics of the rail-bridge system were discussed. The research results show that the displacement admittance of the system has two peak frequencies. These two peak frequencies correspond to the overall first-order vertical bending of the system and the local first-order vertical bending of the F-rail, respectively. With the increase of the distance between the inspection site and the load excitation point, the amplitude of the displacement admittance of the F-rail does not change significantly after the first-order vertical bending frequency of the F-rail. When the excitation is located at the fastener, the amplitude of the displacement vibration of the F-rail in the frequency range of 100—200 Hz is greater than that of the excitation at the non-fastener. The stiffness of the fastener and the distance between sleepers affect the local stiffness of the track structure, thus affect the local first-order vertical bending frequency of the F-rail and the displacement admittance amplitude of the F-rail at this frequency point. The local deformation of F-rail is significant. It is suggested that the effect of F-rail should be considered in the following research of a coupled maglev vehicle-bridge vibration model in time domain.更多还原