Dynamic response feature of electromechanical coupled drive subsystem in a locomotive excited by wheel flat

As a form of wheel tread failure, a wheel flat becomes increasingly severe in a large axle-load heavy-haul locomotive due to emergency braking or skidding idling. The presence of a wheel flat will cause additional impact forces at the wheel-rail interface which is likely to cause a more rapid fatigue failure of locomotive and infrastructure components. Therefore, it is necessary to determine the dynamics effect of the wheel flat on the railway vehicle system so as to allow efficient monitoring and maintenance. In this paper, a co-simulation model which combines the electrical drive subsystem with a locomotive-track coupled dynamics model considering the complete mechanical transmission subsystem has been presented to analyze the dynamic responses of the locomotive under the effect of wheel flats of different sizes. The results show that the existence of a wheel flat will exacerbate the wheel-rail impact and the vibrations of the components in the locomotive. In addition, the frequency associated with the wheel flat and the gear transmission can be extracted from the frequency spectrum of the current signals in a traction motor, which makes it possible to identify the existence of wheel flats or other rotary component defects in time through analysis of the electrical signals without installing extra sensors. © 2021 Elsevier Ltd