Analysis of dynamic wheel/rail interaction caused by measured out-of-round railway wheels

To investigate wheel/rail interaction resulting from actual out-of-round wheels, wheel radial irregularities are
measured from Chinese 25G passenger trains. The measured irregularities are utilized to evaluate vehicle-track
interaction effects by use of a vehicle-track coupled dynamics model. The characteristics of the wheel/rail
interaction are analysed in both time and frequency domains. Simulation results reveal that out-of-round wheel can
result in considerable fluctuation of wheel/rail contact loads. Derivative of wheel radial deviation is an effective
indicator of dynamic wheel/rail force due to the damping effect of vehicle-track system. The vehicle-track coupled
vibration plays a critical role in wheel/rail interaction. Dominant harmonics of the measured wheels are probable to
induce P2 resonances at normal running speeds. Dynamic wheel/rail loads become more sensitive to both higher
and lower order harmonics with increased speeds. Influence of the out-of-round wheel on vehicle vibration is
mainly related to the unsprung mass and primary suspension. Short-wavelength components of the irregularities
stimulate high-frequency vibration of the rail. The rail oscillations are transmitted to the sleepers and ballast bed