Study On The Influence Of The Spring Stiffness And Damping Between The Rails And Sleepers On Rail Corrugation

Rail corrugation is a worldwide problem for centuries. Although researchers all over the world have proposed some remedy measures for different types of corrugation, there is not yet a commonly accepted and effective rail corrugation remedy method. With the rapid development of the urban rail transit, subway lines in our country all are subjected to undulant wear phenomenon to different degrees. Rail corrugation not only affect the service life of the vehicle and track structure, but also produce vibration and noise, which affect the comfort of passengers. What’s more, a sharp increase of wheel-rail forces may cause fracture of rails and axles, and large vibration can cause derailment or other serious accidents. Therefore, the study on rail corrugation is of great significance to the development of the rail transit industry.Based on the viewpoint of friction-induced self-excited vibration of a wheelset-track system causing rail corrugation and the fact of serious rail corrugation occurring on the Beijing subway lines with cologne eggs, an elastic vibration model of a wheelset-track system when a vehicle negotiates a straight track or a tight curve at a steady state is established, which includes four wheelsets and two rails. In the model, the creep forces between the wheels and rails are assumed to be saturated and equal to the normal contact forces multiplied by the friction coefficient. The motion stability of the model is analyzed and the possible frequency of the rail corrugation is predicted using the finite element complex eigenvalue analysis and dynamic transient analysis, which is provided by ABAQUS package. Exploring the influence of the spring stiffness and damping on rail corrugation. The following conclusions can be drawn:(1) Saturated creep force between the wheels and rails can cause self-excited vibration of a wheelset-track system, which results in rail corrugation.(2) Complex eigenvalue analysis results show that the possible frequency of the rail corrugation on a straight track is 241.56、252.65 and 253.14Hz, which appears on the left and right rails, and the possible frequency of the rail corrugation on a tight curve is 494.36、 501.47Hz, which mainly occurs on the inner rail and wheel.(3) Dynamic transient analysis results show that amplitude of the vibration acceleration of the left and right rails on a tangential track is approximately the same, which suggests that the left and right rails have similar corrugation, and amplitude of the the vibration acceleration of the inner rail is obviously bigger than that of outer rail on a tight curved track, which suggests that self-excited vibration of the inner rail caused by saturated creep force between the wheels and rails mainly takes place.(4) Under the same conditions, the frequency of friction-induced self-excited vibration is very close to the measured corrugation frequency in the Beijing metro, which indicates that friction-induced self-excited vibration of the wheelset-track system may be a main cause of rail corrugation occurrence.(5) Stiffness and damping of the cologne eggs have a significant effect on the unstable vibration of the wheels and rails. Theoretically, there is an appropriate stiffness and damping value or range, under which the unstable vibration can be suppressed or eliminated greatly. Higher spring stiffness and damping between the rails and sleepers can effectively suppress the rail corrugation on a straight track, and it’s little effective on the rail corrugation on a tight curve.