Research On The Influence Of Low-order Out-of-round Wear Of Wheels On Abnormal Vibration Of Metro Vehicles

In recent years,the urban railway which is characterized by large carrying capacity,high traffic density,and energy conservation has been favored by megapolis.However,with the increase of the train operating mileage,the low–order out–of–round(OOR)wear of metro vehicle wheels has become a common phenomenon.The OOR wheels cause continuous impact loads with specific frequencies and serious abnormal vibration phenomenon to metro vehicles,which lead to the fatigue failure of vehicle components.Thus,it is of great theoretical and economic significance to carry out a systematic mechanism study on the influence of low–order OOR wear of wheels on abnormal vibration of metro vehicles.Aiming at the abnormal vibration phenomenon of vehicles on a Chinese metro line,this thesis adopts field test and simulation calculation to study the influence of low–order OOR wear of wheels on abnormal vibration of metro vehicles.The main research work includes:(1)The research progress of wheel OOR wear and vehicle abnormal vibration is discussed in detail.The significance of research on the influence of low–order OOR wear of wheels on abnormal vibration of metro vehicles is further pointed out.(2)A metro vehicle–track coupled dynamics model considering the flexibility of vehicle car–body and the typical track structure is established.The established model is verified through the simulation.(3)The effect of the vehicle car–body flexible resonance induced by the low–order OOR wear of the wheels on the vibration of the metro vehicle is studied.The response characteristics of the vehicle car–body when the flexible resonance occurs are revealed.The mechanism of the vehicle abnormal vibration phenomenon caused by wheel OOR wear is carried out by the simulation analysis.The effect of different states of the wheel wear on the flexible resonance vibration of the vehicle car–body is investigated through the numerical simulation.(4)The effect of the floating–slab track resonance induced by wheel eccentric wear on the abnormal vibration of the metro vehicle is studied.The characteristics and key influencing factors of the abnormal vibration phenomenon of the metro vehicle system when the resonance of the floating–slab track system occurs are analyzed.The countermeasure to alleviate the resonance of the floating–slab track system is proposed.The research results show that the flexible resonance of the car–body caused by the low–order OOR wear of the metro wheels and the resonance of the floating–slab track are the main reasons for the abnormal vibration phenomenon of vehicles on a metro line.The abnormal vibration phenomenon of the vehicle caused by the flexible resonance of the vehicle car–body.The main reason is that the first and second–order OOR wear of the wheels at a certain speed stimulates the breathing and torsional modes of the vehicle car–body.For the abnormal vibration phenomenon of the vehicle which caused by the resonance of the floating–slab track.The main reason is that the eccentric wear of the wheel stimulates the vertical bending mode of the floating–slab track,which leads to the coupled resonance between the vehicle and the track.Re-profiling the wheel and optimizing the track structure can effectively avoid the occurrence of the resonance phenomenon of the wheel–rail system.