Study On The Correlation Of The Curve Radius Of Metro Tracks With Rail Corrugation

With the rapid development of urban rail transit,the urban transport efficiency and people’s quality of life have been greatly improved,but the wear problems of wheels and rails have become serious increasingly.Rail corrugation is a common type of rail wear,which refers to the periodic wave-shape abrasion phenomenon occurring on the surface of the rail head.Due to the existence of rail corrugation,the contact conditions of wheels and rails have been changed,the passenger ride comfort and strengths of vehicle and track systems will be affected.The railway administrators spend high maintenance costs every year to remedy it.Therefore,the mechanism of rail corrugation deserves to be studied.And it is of great significance to propose measures to suppress rail corrugation.Based on the theory of the frictional self-excited vibration of wheelset-track systems caused by the saturated creep force,this paper studied the rail corrugation on the subway curved tracks.The following work has been carried out.(1)Using the dynamic analysis software SIMPACK,a vehicle-track system dynamic model was established to study the interaction forces between wheels and rails,the contact positions between wheels and rails on tracks with different curved radii,and to determine whether the creep forces between the wheels and rails were saturated.The research results show that,on the tightly curved tracks,the creep forces between the rails and the wheels of the leading wheelset of the bogies is usually saturated,and the creep forces between the rails and the wheels of the trailer wheelset of the bogies is usually unsaturated.(2)Using the finite element analysis software ABAQUS,a finite element analysis model of the wheel-rail system was established.The complex eigenvalue method was used to analyze and calculate the frequency distribution of the friction self-excited vibration of the wheel-rail system on a curved track,and to study its motion stability and rail corrugation.The complex eigenvalue analysis shows that on tightly curved tracks,the wheel-rail system may generate frictional self-excited vibration under the condition that the creep forces between the wheels and rails are saturated,and this vibration mainly occurs on the inner wheel and the low rail.(3)For the rail corrugation on the inner rails on the large-radius curved track in Shenzhen Metro Line 1,the effect of the stiffness of the fasteners on rail corrugation was studied.The results show larger fastener stiffness and damping can reduce rail corrugation to a certain extent.(4)On large-radius curved tracks,the creep forces between wheels and rails are usually not saturated.But when the train brakes on a downhill track,relative sliding probably occurs between the wheels and rails,and the creep forces become to be saturated,which results in the friction-induced self-excited vibration,and finally rail corrugation.(5)By modifying the geometry of the wheel spokes,the influence of the thickness and tilt angle of the S-shaped spokes on the self-excited vibration of the wheel-rail system was studied.The results show that several measures such as increasing the thickness of the spokes and increasing the angle of the spokes can all reduce the unstable vibration of the wheel-rail system to a certain extent.Hollow axles have an effect on the frictional self-excited vibration when the creep forces between the wheels and rails are saturated,but the hollow diameter of hollow axles does not have no obvious effect on rail corrugation,which means that rail corrugation is less affected by the hollow diameter of hollow axles.