Contact induced wear filtering and its influence on corrugation growth

Abstract

Recent research has suggested that the contact mechanics between the wheel and rail in railway systems may act as a geometric filter for promoting the growth of short pitch wear-type corrugations. It has been proposed that this effect may explain some field observations indicating a speed insensitivity of the dominant wavelength of short pitch corrugation. In this paper, further insight into contact induced wear filtering is obtained and the relative importance of contact filtering and structural dynamics mechanisms on corrugation growth is quantified. In particular, an analytical model of the wear due to the rolling contact of a wheel over a general rail profile is first presented. This model is able to be implemented in an efficient manner and facilitates an investigation into the non-linear behaviour of the dynamic wear not discussed in previous research. In addition, the relative importance of this mechanism when compared to that of dynamic normal force variations on corrugation growth, is determined and quantified. Comparative results indicate that the contact filtering effect only significantly amplifies short pitch corrugation growth when corrugation amplitudes are small (order of 1 μm). Over multiple vehicle passes, this contact amplifying effect is shown to decrease to a negligible level and the peak amplitude shifts to longer wavelengths. These contact filter effects are self-limiting on corrugation growth for wavelengths above the contact patch width. When quantitatively compared against corrugation growth due to structural dynamics, the contact filtering effect is shown to make a much smaller contribution to corrugation growth rates for this model of corrugation development, but it provides a lower bound on corrugation wavelength in accordance with Remington.