Modelling of Spur Gear Dynamic Behaviours with Tooth Surface Wear

In gear transmission systems, the gear tooth surface will get inevitable worn due to various abnormal working conditions. The wear on gear tooth surface will cause deformation of the gear tooth profile. Furthermore, the wear will cause changes in gear tooth mesh stiffness, then deteriorate the gear dynamics. In the past decades, a number of studies had been carried out to investigate the process of gear tooth wear and its monitoring techniques. However, the interactions between the gear dynamics and gear tooth wear are still not got fully investigated. Therefore, this study proposed an eight-degree of freedom dynamic model to study the dynamic behaviours of the gear system with gear wear. When modelling the dynamic behaviours, a modified time-varying mesh stiffness (TVMS) model was derived by employing the potential energy method. The numerical results show that with the increase of the wear depth, the amplitudes at 1 × f_m1 and 2 × f_m2 increase gradually which can reflect the progressive wear process. Furthermore, an experimental study was conducted based on a run-to-fatigue test and the gear vibration responses were studied using the well-known de-noising method Time synchronous averaging (TSA). The experimental validation has a good consistency with the numerical analysis.