Rail corrugation is one of the most serious rail damage problems. The rail surface appears to have wave-shaped uneven wear. The train through the rail corrugation line causes the vehicle violent vibration, which not only affects the running condition of the train, but also leads to derailment accidents in serious cases. In recent years, researchers have proposed various suppression and mitigation measures for rail corrugation. Related research shows that the impact of track structure on rail corrugation is particularly obvious. The paper aims to study the influence of fastener parameters on rail corrugation of the sharp radius curve track, and put forward effective measures to suppress the rail corrugation. Based on the theory of frictional self-excited vibration, a finite element model of the wheel-rail system on the sharp radius curve track supported by DTVI2 fasteners was established. In the finite element model, the rail pad was represented with solid element, the frictional contact between the rail and the pad was fully considered, while the spring preload was applied to simulate the preload effect of the clips on the rail. The friction self-excited vibration characteristics of the wheel-rail system of the metro vehicle were studied through complex eigenvalue analysis and transient dynamic analysis. The complex eigenvalue analysis results showed that the wheel-rail system occurred with an unstable vibration frequency of 499.46 Hz. The modal analysis showed that the deformation occurred mainly on the inner wheel and low rail, which indicated that the rail corrugation was most likely to occur on the low rail under the same line conditions. The transient dynamic analysis results showed that a self-excited vibration with a principal frequency of 504.64 Hz occurred in the low rail, which was close to the frequency of self-excited vibration obtained from the complex eigenvalue analysis. Therefore, it could be inferred that the frictional self-excited vibration with a frequency of about 500 Hz occurred in this section of the wheel-rail system was the main cause of rail corrugation. A long-term investigation of rail corrugation characteristics of Chengdu Metro Line 6 was carried out. The finite element prediction results were compared with the field test results, and the root cause of rail corrugation in this section was revealed. Finally, a parametric analysis of the material properties of the under-rail pads and the structural parameters of the fasteners was carried out with the finite element model, and the variation law of their effects on rail corrugation was obtained. On the sharp radius curve track supported by DTVI2 fasteners, the self-excited vibration at 500 Hz was excited by saturation creep force between the wheels and rails in the wheel-rail system. This unstable vibration would cause the wheelset-track system to produce rail corrugation with wavelength of 30 mm. When the Young's modulus of the under-rail pad is in the range of 10 MPa to 50 MPa, the equivalent damping ratio first decreased from -0.015 2 to -0.016 9 and then increased to -0.014 2. The damping factor varied from 0 to 0.000 1, and the equivalent damping ratio of the unstable vibration of the wheel-rail system increased from -0.016 9 to -0.010 2. The change in Poisson's ratio did not cause a significant change in the equivalent damping ratio of the system. The fastener spacing varied between 575 mm and 675 mm, and the equivalent damping ratio also decreased from -0.016 3 to -0.019 0 with increasing fastener spacing. At the same time, the equivalent damping ratio increased with the increase of the clips preload. Results show that selecting a appropriate Young's modulus of the under-rail pad can reduce the occurrence probability of rail corrugation caused by wheel-rail friction self-excited vibration. The higher damping coefficient of the under-rail pad has a certain suppression effect on the self-excited vibration of the wheel-rail system. Poisson's ratio has less effect on the occurrence of rail corrugation on the small radius curve track. Reducing the fastener spacing can slightly reduce the tendency of rail corrugation. Increasing the clips preload can suppress the rail corrugation caused by the frictional self-excited vibration of the wheel-rail system. In this study, based on the mechanism study of rail corrugation, several main factors in rail fasteners are considered to influence the law of rail corrugation. This study provides reference for proposing the optimal design of rail support structure to suppress rail corrugation. © 2024 Chongqing Wujiu Periodicals Press. All rights reserved.
