Analysis Of Longitudinal Dynamic Characteristics Of Suspended Monorail Train-bridge System

With the rapid development of the social economy and the growth of the urban population,the urban rail transit industry in China has been developed rapidly in the past decade.The suspended monorail transit is,as a new type of the rail transit,recently applied in China due to its many advantages of safety,environmental protection,low construction cost,strong environment adaptiveness and less ground space,etc.A three-dimensional urban traffic network system can be therefore constructed by combing the suspended monorail transit with the ground road traffic and the metro,which is an effective solution to the problem of urban traffic congestion.At present,the technology development of the suspended monorail transit is vigorously promoted,and the suspended monorail test lines have been built in many places.Clearly,the suspended monorail would have a broad application prospect,and accordingly an in-depth research on the potential problems in its engineering application should be urgently required.The existing research work mainly focus on theoretical analysis and the theoretical models are lack of the experimental verification.In addition,the longitudinal dynamic characteristics of the suspended monorail system have not been studied at present stage,and the dynamic characteristics of the suspended monorail vehicle-bridge coupling system have not been fully studied,which leads to the lack of sufficient theoretical guidance for the application of the suspended monorail transit.Therefore,a research on the analysis of longitudinal dynamic characteristics of the suspended monorail train-bridge system is carried out in this thesis based on the suspended monorail transit test line with new energy in Chengdu.The main research works of this thesis are as follows:(1)The development history,structural type,and characteristics of the suspended monorail is summarized,and the research status of the suspended monorail is analyzed,which points out the research direction and focus in this thesis.(2)In this thesis,the mechanical characteristics of rubber tires used in suspended monorail vehicles are analyzed.A suspended monorail vehicle with 28 degree of freedom considering the longitudinal motion is established based on the theory of the multi-rigid body dynamics,and a finite element model of the suspended monorail bridge is established adopting the mode superposition method.According to the braking characteristics of the suspended monorail train,the longitudinal coupling vibration of the suspended monorail train-bridge system is analyzed from the aspect of deceleration.The program of longitudinal dynamics simulation of the train-bridge system is compiled in MATLAB software.The dynamic simulation analysis of the vehicle-bridge system is conducted under the straight-line operating condition with a constant train speed and the straight-line emergency braking condition respectively,obtaining the dynamic responses of the system under different operating conditions.(3)Based on the test line of Chengdu new energy suspended monorail,the field test was conducted and the test overview,test plan and corresponding dynamic response evaluation index were introduced.The dynamic responses such as the vibration acceleration of the vehicle,the vibration acceleration of the midspan and the pier and the dynamic deflection of the bridge were measured.The simulation model established in this thesis is verified by comparing the measured results and the dynamic simulation results of the vehicle-bridge system.(4)The longitudinal dynamic characteristics of the suspended monorail vehicle-bridge coupling system are analyzed by using the model established in this thesis.Specifically,the effects of main parameters such as vehicle load,braking position,bridge span,pier height and running plate thickness on the longitudinal dynamic performance of the system are studied.The results can provide useful reference for the design of the suspended monorail transit.