A Numerical Simulation Of Influence Of Primary Suspension And Rail Fastener Parameters On Rail Corrugation

With the vigorous development of urban rail transit systems,the operating environment of metro vehicles becomes more complex,and the interaction environment of wheel and rail becomes more serious.Rail corrugation is one of common track damage problems induced by wheel/rail rolling contact.When a vehicle runs on the rail section with rail corrugation problem,this violent dynamics interaction will lead to forced vibration of vehicles and sharp noise which impact on the comfort of passengers and damage of the parts of the vehicle and track.Moreover,serious rail corrugation can even cause traffic accidents.Although the study on rail corrugation has lasted for one hundred years,there is not a clear and unified viewpoint of the formation mechanism of rail corrugation could be accepted by researchers all over the world.At present,the only effective measures to reduce the rail corrugation problem are rail grinding and rail replacement in operating maintenance work,but new rail corrugation will be produced after taking these remedies.Therefore,understanding the formation mechanism of rail corrugation and taking measures to eliminate the production conditions of rail corrugation from the source is the best way to solve this problem.Professor Chen from Southwest Jiaotong University proposed a viewpoint that the friction-induced vibration of the wheelset-track system may lead to rail corrugation.Chen considers that when a metro vehicle runs on a sharp curved track,the creep force between the leading wheelset and track will be saturated,and the saturated creep force approximately equals to the friction force.The friction-induced vibration of the wheelset-track system easily occurs under the action of the saturated creep force,which induces the fluctuation of the friction work and brings about the rail corrugation treads.In this article,we use the finite element software ABAQUS to establish a finite element model of a wheelset-track system and perform transient dynamic analysis and complex eigenvalue analysis.Through the complex eigenvalue analysis and transient dynamic analysis of the model,the stability characteristics of the model in frequency domain and time domain are studied,and the generation propensity of frictional self-excited vibration of the wheelset-track system is predicted.The main research works of this paper are presented as follows:(1)The author made an review of rail corrugation studies.The author has reviewed railcorrugation study progresses made by domestic and foreign scholars,and their field investigations and tests on rail corrugation in earlier period.Then the theoretical models of rail corrugation in time domain and frequency domain in the literature are discussed accordingly.Finally,a brief introduction of the search works from the perspective of influencing factors.(2)The author studied the dynamic behaviors of friction-induced vibration of the wheelset-track system when the metro vehicle passes through on a sharp curved track using the transient dynamic analysis provided by ABAQUS.Based on the study of vertical vibration acceleration signals of the nodes on the rail surface and normal contact force signals between the wheel and rail,author has found that the wheelset-track system self-excited friction vibration induced by the saturated creep force will cause fluctuations of the normal contact force and the vertical acceleration,and the amplitudes of the fluctuations on the low rail is much larger than those on the high rail,which suggests that self-excited friction vibration is more easily to occur on the low rail.The dominant frequencies of the vertical vibration acceleration and the normal contact force are all about 490 Hz.This frequency is in agreement with the frequency range of rail corrugation obtained from the field test measurement.(3)The author studied the stability of the wheelset-track system using the complex eigenvalue analysis method provided by ABAQUS,which can predict the main frequency of self-excited friction vibration and the associated vibration modes.The vibration dominant frequency obtained by using complex eigenvalue analysis method is 498.12 Hz,and this frequency is very close to the frequency obtained by using the transient dynamic analysis method,this mean that complex eigenvalue analysis method is accurate.The influence of the damping and stiffness of the integral and unilateral fastener,the damping and stiffness of primary suspension on the occurrence propensity of the self-excited friction vibration are also discussed.And from the angle of influence factors,this paper puts forward a method to suppress the rail corrugation.