Study Of The Prediction Model And Suppression Measures Of Rail Corrugation On Tight Curves

With the improvement of the economic level,domestic rail transit systems have been vigorously developed,but a long-standing problem,rail corrugation,has not been fully solved.The rail corrugation makes the vehicle generate strong vibration when the train passes through the rail section with rail corrugation,and sharp noise will appear in the section with severe corrugation,which seriously affects the comfort of passengers.In addition,the irregularity of the rail surface due to rail corrugation will change the contact state of the wheel and rail and cause a great impact between them,which will damage the vehicle and track system and seriously endanger the train running safety.The railway departments will spend huge amounts of money every year for the elimination of rail corrugation and the replacement of old rails.Although there are many research results on rail corrugation,the researchers have different understandings on the formation mechanism of rail corrugation.So far,there is no way to eliminate rail corrugation completely.Therefore,it is very important for rail transit systems to correctly understand the formation mechanism and development process of rail corrugation and to eliminate rail corrugation from the source.The dynamics and finite element models of a wheelste-track system on a sharp curved track are established by using Simpack and Abaqus softwares based on the theory proposed by Professor Chen that the frictional self-excited vibration leads to rail corrugation.The phenomenon of rail corrugation is studied by complex eigenvalue and instantaneous dynamics analysis methods provided by finite element software.The main works and results of this paper are summarized as follows:(1)The dynamic model on a sharp curved track is established by using Simpack software to study the creep force saturation state between the wheel and rail.The results show that the creep force between the leading wheelset and rail is usually saturated.Based on the result,the finite element model of the wheestet-track system including the leading wheelset is established.(2)The frequency range of rail corrugation on a sharp curved track is about 305.56~451.38 Hz by analyzing the data measured in field tests.Through the analysis of complex eigenvalues,it can be known that the main unstable vibration frequency of the wheelset-track system is 322.99 Hz when the wheelset is simulated by interference fit between the wheel and axle,which is consistent with the frequency of rail corrugation measured in the field investigation,and the simulation result in accuracy is better than that when the integral wheelset without separation between the wheel and axle is simulated.Meanwhile,the influence of the element size of the wheelset-track contact area is studied.It is concluded that the simulation results using the model established in the present paper are higher than those using the models with integral wheelset in accuracy by comparison.(3)Transient dynamics analysis is conducted with the high-precision rail corrugation prediction model which is simulated by interference fit between the wheel and axle.The dynamics response results show that the wheel-rail contact force and the vertical vibration acceleration of the low rail will fluctuate drastically,and the amplitude of the fluctuation is much higher than that on the high rail.The calculation results show that the rail corrugation is more likely to appear on the low rail,which is consistent with the rail corrugation phenomenon of the actual line.The PSD analysis of the time-domain response results of the low rail is conducted.The analysis results show that the fluctuation frequency of the dynamics response signal is very similar to the main unstable vibration frequency obtained in the complex eigenvalue analysis,which verifies the accuracy of the complex eigenvalue analysis results.(4)High-precision rail corrugation prediction model is used to study the effect of unilateral wheel-track friction coefficient and magnitude of interference within a reasonable range on the self-excited vibration of the wheelset-track system.The calculation results show that the value of interference has little effect on the trend of friction self-excited vibration of the system.The friction coefficient between the outer wheel and high rail has little effect on rail corrugation,while the friction coefficient between the inner wheel and low rail has a significant influence on the trend of rail corrugation.Appropriately reducing the friction coefficient between the inner wheel and low rail is beneficial to restrain the generation of rail corrugation.At the same time,the phenomenon of rail corrugation on a track with GJ-III fasteners is studied.The results show that DTVI-II fasteners which has high vertical stiffness than the GJ-III fasteners can completely eliminate the rail corrugation on a straight track.Although it can reduce the tendency of unstable vibration and has a certain inhibitory effect on the rail corrugation,it can not eliminate rail corrugation on a sharp curved track.