Properties of wheel/rail longitudinal creep force due to sinusoidal short pitch corrugation on railway rails

The periodic wear on rails with wavelengths between 20 mm and 100 mm is called short pitch corrugation and the state of the wheel/rail rolling contact with short pitch corrugation is highly non-steady. This paper focuses on characteristics of wheel/rail longitudinal creep forces due to sinusoidal short pitch corrugation on the rail based on Kalker's variational method. It is found that longitudinal creep forces from a nonsteady-state model have decreased amplitudes and phase lags compared with the results from the steady state theory. A system identification method is used to analyze the properties of longitudinal creep force. For sinusoidal short-pitch corrugations of a similar depth, the fluctuating component of the longitudinal creep force can be described using a transfer function of a dimensionless frequency defined as the ratio of the semi-axis length of the contact patch to the wavelength of the short-pitch corrugation. Finally transfer functions are used to calculate the non-steady longitudinal creep forces under multi-wavelength short pitch corrugations and results are in good agreement with those obtained from the variational method.