Dynamic Simulation of Tooth Root Crack Failure in Planetary Gearbox Based on Torsional Vibration Signal

Vibration-based methods has been widely used for diagnosing tooth root crack fault in planetary gearbox. Compared to the traditional transverse vibration signal, the torsional vibration signal is theoretically free from the modulation effect by time-varying transfer paths, so it has simple frequency contents to extract fault signature easily. In this paper, torsional vibration signal which is extracted in dynamic simulation models, is analyzed to diagnose tooth root crack fault. Firstly, a rigid-flexible coupling model of a healthy planetary gearbox is constructed and verified. The model can obtain a fairly accurate result with much low time cost. Then, based on model of healthy planetary gearbox, three typical crack fault models are constructed. This is aimed at extracting dynamic response of fault planetary gearboxes. Finally, transverse signals and torsional signals are analyzed to diagnose tooth root crack fault. The results obtained indicate that it is an effective method to diagnose planetary gearbox crack fault via torsional vibration signal analysis, and provide a theoretical reference for diagnosis of tooth root crack failure in planetary gearbox.