Failure dynamic modelling and analysis of planetary gearbox considering gear tooth spalling

Abstract The spalling mechanism and influence of fault evolution are studied for the gear system of wind turbine by analyzing the dynamic responses. The lateral-torsional dynamic model is proposed in this paper for multistage gear system with gear spalling fault, which considers the influences of nonlinear factors such as tooth friction, sun gear support, time-varying mesh stiffness, gear backlash and comprehensive mesh error. Based on the improved energy method, a calculation model of gear spalling fault is performed to analyze the effect of fault on the time-varying mesh stiffness. At the same time, the bifurcation diagram, time series, phase trajectory, Poincare map, spectrum diagram and related three-dimensional diagrams are used as tools to qualitatively analyze the dynamic response of gear system. The results show that the fault characteristic frequency of sun gear is sensitive at low excitation frequency, which indicates that it is suitable for fault detection. In addition, the dynamic behavior of the system becomes more complex as the spalling becomes deeper.