Torsional Vibration as a Method of Diagnostic Tool for Wheel Flatness

Wheel flat frequently occur during the operation of high-speed train, which will deteriorate the vibration condition of the components of vehicle and track system. Besides, it is likely to threaten the running safety of high-speed train. Hence, deep insight into the fault features of the wheel flat is urgently necessary for prevention of the induced disastrous consequences. This paper aims to investigate the effectiveness of using the torsional vibration signal as a diagnostic tool for wheel flatness of high-speed train. The vehicle-track spatial coupled dynamics model considering the dynamic effects of traction transmission system is employed. The nonlinear factors, such as time-varying mesh stiffness, fraction forces, gear backlash, track geometry irregularities and wheel-rail interactions, are considered in detail. Besides, the wheel flat model is incorporated into the dynamics model to obtain the vibration responses. Some signal processing techniques were utilized to analysis the fault diagnostic results from the torsional vibration. It was found that the torsional vibration of traction transmission system successfully detected the wheel flat. As a result, the torsional vibration can be considered an effective approach for wheel flat condition monitoring.