Analysis Of Dynamic Characteristics Of Train-track-bridge Of Heavy Haul Railway

Heavy haul railway has the advantages of low cost,high efficiency,large traffic volume and less pollution,which has been the goal of our country and even the whole world.With the increasing speed and axle load of heavy haul railway train,not only will the vibration response of track structure and bridge structure under train load be intensified,fatigue damage and deformation be more easily produced,but also the interaction between Train-Track-Bridge system will be intensified,so that the safety of train running on bridge will be reduced,which will lead to derailment accident.Therefore,it is necessary to systematically analyze the dynamic response of vehicles,tracks and bridges.Firstly,the development status of heavy haul railway at home and abroad and the research status of vehicle-bridge coupling dynamics are described.Based on the coupling theory of vehicle-rail-bridge system,the finite element equation of ballasted track bridge of heavy haul railway is deduced.Then the parameters of bridge,track and vehicle are selected.The solid model of simply supported bridge is established by using finite element software ABAQUS,and the model of flexible track and C80 freight car is established by using multi-body dynamic software UM.The vertical dynamic model of single vehicle of track-bridge is compiled by using MATLAB language.Comparing with UM.Before the simulation,the excitation factors of track irregularity and the evaluation criteria of vehicle,track and bridge vibration performance in vehicle-rail-bridge coupling system are introduced in detail.The key steps to realize simulation model are introduced in detail.In the analysis of the train-rail-bridge system,the dynamic response of the system is studied from three aspects: train speed,axle load and train formation.It is concluded that with the increase of speed and axle load,the response of the train-rail-bridge system also increases in varying degrees.The derailment coefficient and wheel load reduction rate of the air-weight mixed train are the largest,and it is easier to derail.Secondly,the effects of the stiffness changes of the fasteners and the ballast bed on the system are studied separately.It is found that the stiffness of the fasteners has a certain influence on the safety and stability of the vehicle,has a significant impact on the track structure,and has little impact on the bridge structure.The stiffness of the ballast bed has little impact on the safety and stability of the vehicle,has a limited impact on the response of the rail,and has a significant impact on the sleeper and bridge structure.Finally,the damping ratio and track irregularity excitation which affect bridge vibration are studied.It is found that the damping ratio can effectively reduce the vibration response of the bridge,especially at resonance speed,which has certain influence onthe vibration acceleration of vehicles.The effects of different track spectra on the response of vehicle-rail-bridge system are compared,and the influence characteristics of irregularity on the system and the quality of track spectra are obtained according to the data comparison.