Research On Meshing Characteristics And Dynamic Response Of Rack Railway On Large Slope Bridge

Rack railway is a kind of special application in the mountain area of rail transit ways,to overcome the ordinary railway wheel-rail adhesion insufficient defects in large slope area,with strong climbing ability,good terrain adaptability and large capacity and a series of advantages.It has broad application prospects in the construction of mountain sightseeing and tourism rail lines in our country.However,there is no experience in the construction and operation of rack railways in our country at present,and there are certain deficiencies in the research on application and track mechanical behavior.This paper takes the rack railway on the large-slope bridge as the research object,and analyzes the key operation technology and characteristics of the rack railway track system.Based on the finite element theory and multi-body dynamics method,the meshing analysis model of the rack system and the coupling dynamic analysis model of the large-slope rack vehicle-trackbridge are established.The meshing characteristics of the rack drive system and the dynamic response law of the large-slope rack system are studied,in order to provide a theoretical reference for the construction of rack railways in our country.The main research work of this paper includes the following:(1)By sorting out the relevant technical data of the rack railway at home and abroad,the key technical characteristics in the process of structural design and operation of the rack railway are summarized.It mainly includes the common rack system driving mode and its characteristics in rack vehicles,the meshing characteristics and design methods of involute rack wheels,the connection method of rack structures,the common anchoring measures for rack railway track structures in large slope areas,and the layout method and design principle of the transition area between the rack and the wheel rail.(2)The meshing analysis model of rack system and the coupling dynamic analysis model of large-slope rack vehicle-track-bridge are established.Firstly,according to the actual meshing relationship between the rack wheel and the rack,the meshing analysis model of the rack system is established based on the finite element method,and the accuracy of the model is verified by comparing with the theoretical calculation value of meshing.Secondly,based on the multi-body dynamics theory and the finite element method,the coupled dynamic analysis model of the large-slope rack vehicle-track-bridge is established.The model is mainly composed of three parts: rack vehicle model,track model and bridge model.The rack vehicle model is composed of a special wheelset with rack wheels,and meshing drive is used in the analysis process to simulate the actual running state of the rack vehicle.(3)Based on the established meshing analysis model of the rack system,the meshing characteristics of the rack system under different operating slopes and vehicle axle loads are studied.In the analysis process,according to the actual working characteristics of the rack drive system,the driving force required by the train to overcome the resistance of the ramp is converted into the driving torque exerted on the rack wheel.Considering the influence of dynamic load factors,the meshing characteristics of the rack system are analyzed from the angles of the meshing strength of the rack,the contact strength of the gear tooth surface and the bending strength of the tooth root.The safety and reliability of the rack drive system under different line operating conditions are evaluated.(4)Based on the established dynamic analysis model of the rack railway vehicletrack-bridge coupling system,the dynamic response of the rack railway vehicle-trackbridge coupling system on the large-slope bridge is studied.Firstly,based on the dynamic analysis model of the rack vehicle,considering the influence of the track irregularity,in the rack drive mode,the safety and comfort of the vehicle operation under different operating gradients of the line are analyzed.Secondly,by converting the wheel(rack)rail force calculated based on the vehicle model into the moving load excitation,and inputting it into the track-bridge finite element analysis model,the dynamic response characteristics of the track and bridge structure under the driving condition are studied.The influence of the line operating slope and the longitudinal stiffness of the bridge pier on the dynamic response of the track and bridge structure is further analyzed.There are 70 figures,30 tables and 80 references.