Research On Suppression Measures Of Rail Corrugation On Tight Curved Tracks

Nowadays rail transit has become a significantly important part of transportation tools in our country.Rail transit can not only ease the traffic pressure among cities,but also promote economic exchanges among regions.It has made important contributions to the steady and rapid development of China’s economy.However,rail transit faces many technical difficulties.Rail corrugation is one of the technical difficulties which we often encounter.The existence of rail corrugation will aggravate the vibration between the wheel and rail.On the one hand,the service lives of the components of vehicles and tracks are reduced,and on the other hand,the passenger ride comfort is greatly reduced.Rail transportation departments all over the world spend a lot of energy to reduce adverse effects from corrugation each year,but the results are not as good as expected.The understanding of rail corrugation is not enough.Therefore,it is of great significance to recognize the mechanism of rail corrugation and propose measures to remove or suppress rail corrugation.Under the condition of tightly curved tracks,for example,the track radius is less than or equal to 350 m,almost all low rails will be subjected to corrugation.A finite element model of a wheel-rail system was established by ABAQUS based on the theory that the saturated creep force between the wheel and rail induces frictional self-excited vibration to result in rail corrugation.The author’s research work and results are summarized as follows:(1)A vehicle system dynamics model was established by using the dynamics analysis software of SIMPACK.Firstly,the saturation states of creep forces are analyzed under the curved track of radius 300 m.Research results show that the creep forces between the wheels of the leading wheelset of each bogie and rails are saturated under the tightly curved track of radius 300 m.Then a finite element model of the wheel-rail system was established by using the dynamic parameters when a vehicle passed through the tight curved track to analyze the motion status of the wheel-rail system.Meanwhile,the stability of the wheel-rail system was analyzed by using the complex eigenvalue analysis method and the transient dynamic analysis method.Results show that the motion of the wheel-rail system is unstable under the tightly curved track.The unstable vibrations of the inner wheel and the low rail is generated,which probably causes rail corrugation.This result is consistent with the actual field measurement of rail corrugation.Finally,the transient dynamic method was used to analyze the oscillation dynamic of the wheel-rail system.Results show that the normal contact force between the inner wheel and low rail and the vertical vibration acceleration of the inner wheel and low rail are significantly higher than the normal contact force between the outer wheel and high rail and the vertical vibration acceleration of the outer wheel and rail,respectively.The results suggest that the rail corrugation is more likely to occur on the inner rail,and this results is basically consistent with the results obtained using the complex eigenvalue analysis method.(2)The finite element models of wheels with and without web holes were established by ABAQUS to study the effect of wheels with web holes on rail corrugation on the curved track of radius 350 m by using the complex eigenvalue analysis method.Results show that the wheel with web holes has a certain suppression of rail corrugation on tightly curved tracks.An appropriate hole distance can increase the stability of the wheel-rail system and reduce the occurrence probability of rail corrugation.In addition,the influence of the diameter of the wheel web holes has a certain effect on the occurrence of rail corrugation,but the effect is not obvious.In comparison with the model of the wheel without web holes,the wheel with four web holes can increase the stability of the wheel-rail system and reduce the occurrence tendency of rail corrugation,but the wheel cannot remove completely rail corrugation.(3)The finite element models of the wheel web with and without damping coating were established by ABAQUS to study the effect of the web damping coating on rail corrugation on the curved tracks of radius 300 m using the complex eigenvalue analysis method.Results show that in the presence of coating,the occurrence propensity of rail corrugation can be reduced by adding damping coatings on the inside surface or two side surfaces of the web.At the same time,the motion stability of the wheel-rail system can be effectively improved.The occurrence propensity of rail corrugation gradually decreases as the thickness of the coating increases when the coating on the inside surface or two side surfaces of the web.The occurrence propensity of rail corrugation will be increased by adding the damping coating on the outer sides of the wheel webs,and the stability of the wheel-rail system will be reduced.And as the thickness of the coating increases,the occurrence propensity of rail corrugation gradually increases.The damping coefficient of the coating make a great influence on rail corrugation.When the damping coefficient of the coating on the inner side surface of the wheel web is increased to 1.5e-3,rail corrugation can be suppressed effectively.