Analysis On Characteristics And Influence Of Wheel Polygon Of A Certain 300km/h High-speed Train On A Certain Line

Polygon wear of train wheels can be widely found in railway transportation,it is also a common phenomenon of abnormal wear of high-speed train wheels.Wheel polygonization can affect passengers'riding comfort,and will harm the driving safety of trains in a critical condition.However,the academic community has not reached an agreement on the formation mechanism of wheel polygonization,therefore,the problem of the mechanism and important influence factors the formation mechanism of wheel polygonization still need to be explored.Based on the field test and investigation,the characteristics of polygon wear of the 300km/h high-speed EMU trains are summarized,the effects of wheel polygon wear on vibration and noise characteristics of trains are studied,the key conditions and induction factors are explored,all these aspects can provide a basis for the study of the mechanism and countermeasures of wheel polygonization.The main research work is as follows:Through the results analysis of the surface condition test of wheels before re-profiling,it can be found that the train wheels have obvious polygonal wear of 18¹9^th order.These orders both have a significant relation with the wheel diameters,for example,the 20^th-order polygon wear mainly exists on the wheels with a diameter of around 920mm,the 19^th-order polygon wear mainly exists on the wheels with a diameter of around 875mm,the 18^th-order polygon wear mainly exists on the wheels with a diameter of around 840mm.Tracking test of the surface state of the wheels is made during the two re-profiling cycles period,and the development regularity of the wheel polygon wear with the running mileage is obtained.Based on the model of the vehicle-track coupled dynamics and the mechanism of wheel-rail wear,the wheel polygonal wear simulation calculation model was established,and the effect of wheel diameter and speed on wheel polygonal wear have been studied.Results show that when factors like the excitation frequency,the wheel diameter and the running speed meet a certain relationship,i.e.,when the wheel circumference can be divisible by the excitation wavelength,a significant wheel polygonization is more likely to be occurred.According to the test of the bogie system,it can be found that the wheelset and the bogie frame have a natural frequency around 580 Hz.However,around this frequency,factors like when the vibration isolation of the primary suspension is weak,the eccentricity of the wheel-rail contact surface,the irregularity of the rail can increase the probability of the resonant of the bogie system around 580 Hz,all of which will result in the generation of wheel polygon wear.The variation law of the development of wheel polygon wear of vibration and noise characteristics of the bogie area is studied by testing the state of the wheel surface and the vibration and noise of the bogie at the same time.The influence of the wheel polygon wear of the train on the vibration of the track system is studied through the test of dynamic response of the track.Results show that for vehicle systems,wheel polygon wear can significantly increase the vibration of the axle box,frame and body and the noise level of the bogie area.It will also cause significant harmonic frequency band in 400⁹00Hz of the noise spectrum of the bogie area when the sleeper-passing frequency is remarkable,and then expanding the influence on the noise frequency band.For rail systems,wheel polygon wear can significantly increase the vibration of the rails and fasteners,thus the broken possibility of the fasten system will be increased.