Influence of rail side lubrication and slip rate dependent effects upon the corrugation on the metro small curve track

For investigating the rail corrugation characteristics of metro small curve track under the combined effect of rail side lubrication and slip rate dependence, by developing a three-dimensional vehicle-track coupling numerical model, the wheel-rail (WR) contact stick-slip (SS) characteristics under different transition areas of rail side lubrication in the presence of corrugation were analyzed. Meantime, on the basis of considering the friction slip rate dependence, the SS vibration characteristics under different rail side lubrication conditions were further analyzed to understand the effect mechanism of rail surface friction characteristics on corrugation. The results show that, when there is rail side lubrication, both inner and outer WR systems have the possibility for SS vibration, and the longitudinal SS vibration intensity is greater than the transverse SS vibration intensity; the SS vibration intensity of the inner WR system is greater than that of the outer WR system, indicating that the inner rail is more susceptible to corrugation and the corrugation is more acute. With the expansion of the rail side lubrication range, the standard deviations of longitudinal and transverse adhesion coefficients decrease, illustrating that the expansion of the lubrication range can reduce the SS vibration intensity of WR system. When the co-effects of rail side lubrication and slip rate dependence are considered, the increase of the rail side lubrication range leads to the increase of standard deviations of adhesion coefficients, which may be related to the enhancement of slip effect induced by the increase of the lubrication range. The introduction of slip rate dependent effect can reduce the standard deviation of the WR adhesion coefficient, which demonstrates that the slip rate dependent effect can ease the degree of SS vibration of WR system, thus reducing the probability of corrugation occurrence caused by the SS vibration.