中低速磁浮轨排结构自振特性及控制OA

[Objective]In order to avoid abnormal vibration of the track panel structure in the medium-and low-speed maglev projects,this study takes the track panel structure and technical standards of Beijing S1 line as an example and investigates the natural vibration characteristics of the medium-and low-speed maglev track,as well as the influence of fastener stiffness and support spacing on natural vibration characteristics,using the finite element simulation method.[Methods]Firstly,the natural vibration characteristics of the free and constrained modes of the medium-and low-speed maglev track panel structure were calculated and analyzed,and the vibration problem of the track panel structure was further analyzed in combination with the structure-excitation relationship.Then,the influence of fastener stiffness,support spacing,and other factors on the natural vibration characteristics of the track panel structure was studied,and the degree of influence and sensitivity of each factor were quantitatively evaluated.[Results]The results showed that the constrained mode frequency of the track panel structure was higher than the free mode frequency,and the structural mode shapes exhibited a combination of bending and torsional vibrations.In the low-frequency range,the modes were mainly manifested as overall vibrations.As the frequency increased,the mode shapes were dominated by local vibrations with short wavelengths and multiple wave numbers.The excitation frequency of vehicle operation was the main controlling frequency in the design of the track structure.As the speed of the medium-and low-speed maglev system increased,the natural frequency of the track structure should be raised correspondingly.Compared to the unit track panel length,adjusting the support stiffness or support spacing of the track panel was easier to increase the first-order natural frequency of the track panel structure.Specifically,the support stiffness was positively correlated with the first-order natural frequency of the track panel structure,while the support spacing was negatively correlated with it.In engineering applications,improving fastener stiffness was the simplest and most effective measure to increase the natural frequency of track panel structures.The curve radius had little effect on the first-order natural frequency of the track panel structure,indicating that the vibration problem of the track panel structure did not constrain the plan alignment design of the medium-and low-speed maglev system.When the maximum operating speed of the train was 100 km/h,the minimum track panel length could be controlled at 3.6 m,the maximum sleeper spacing could be set to 1.2 m,and the fastener stiffness could be adopted as 75 kN/mm.When the train speed increased to 160 km/h,it was recommended that the fastener stiffness should not be lower than 100 kN/mm,and the track panel length and the sleeper spacing should be comprehensively determined by considering the overall system requirements.[Conclusion]The research methods and findings can provide guidance and reference for similar engineering projects.