Research And Analysis On The Influence Of Wheel Out Of Roundness On Train Motion

With the increasing number of high-speed train lines,high-speed train wheel wear will appear in the circumferential direction after running a certain mileage.The wheel out of roundness will have a bad impact on the train operation,leading to the increase of wheel rail force,which is easy to cause severe vibration of the train.When the high frequency vibration generated by the wheel polygon is coupled with the modal frequency of the wheelset,it will further cause the abnormal wheel rail force,so the research on the driving safety and reliability of high-speed trains becomes particularly important.The specific analysis is as follows:Based on the CRH3 train dynamics model,the substructure analysis module of finite element analysis software and the flexible body module of multi-body dynamics simulation software are used for joint modeling.The wheelset and frame model of the train are reduced and flexible,and the rigid flexible coupling dynamics model is established.The differences between the rigid body model and the flexible body model on the dynamic behavior of the train are compared and analyzed,The vibration response of the rigid flexible coupling model under external excitation is more obvious,so it is closer to the actual working condition.The influence of rigid flexible coupling train model on dynamic performance of train system under different wheel polygon orders and out of roundness amplitudes at running speeds of 100km/h,200km/h and 300km/h is simulated and analyzed,including vertical wheel rail force,lateral wheel rail force,critical speed of hunting instability,derailment coefficient and wheel load reduction rate.It is found that the increase of the order of wheel polygon has more obvious effect on the critical speed of serpentine instability than the increase of the amplitude of wheel out of roundness;The wheel polygon has little effect on derailment coefficient and ride comfort;When the speed level is 300km/h,the wheel rail vertical force and the wheel load reduction rate will exceed the limit standard.Through the simulation and analysis of the vibration response of the wheel,rail and frame caused by the wheel out of roundness,it is found that the low-frequency rigid vibration of the train caused by the track irregularity and the polygonal impact frequency f_p of the wheel are the main factors affecting the wheel rail vertical force.When the impact frequency is close to the natural frequency of the wheel set,the coupling vibration will occur,resulting in the abnormal increase of the wheel rail force;The influence of wheelset modal vibration on wheel rail force increases with the increase of wheel out of roundness amplitude,and the change is not obvious when the amplitude is higher than 0.06mm;When the train speed increases,the track irregularity will stimulate the torsional and first-order bending vibration modes of the wheelset.This paper analyzes the vibration frequency range of wheelset with abnormal wheel rail force and the corresponding train running speed range when the polygonal impact frequency is close to the natural frequency of wheelset,and puts forward the control measures to avoid vibration coupling between polygonal wheel impact frequency and wheelset modal deformation frequency when the train is running.In this paper,the dynamic response of wheel polygon to train and the vibration response of wheel rail are studied to provide reference for ensuring the safety of high-speed train operation.