Nonlinear dynamic analysis of GTF gearbox under friction excitation with vibration characteristics recognition and control in frequency domain

摘要

A non-linear dynamic model of a fixed-axis spur planetary gear-rotor-bearing system for the gearbox in Geared Turbofan (GTF) engine is established that considers the time-varying meshing stiffness, tooth face friction, transmission errors, gear backlash and bearing clearance. By using Runge-Kutta numerical integration, the dynamic responses are solved, analysed, and illustrated with the bifurcation parameter, frictional coefficient. The motions of the gear system and diverse non-linear characteristics are identified through the global bifurcation, FFT spectra, Poincare map, and phase portrait. The results reveal that the planetary gear-rotor-bearing system exhibits abundant non-linear behaviours. In addition, the dynamic response under varying frictional coefficients is demonstrated with a 3D frequency spectrum, furthermore, the vibration characteristic is investigated and controlled through changing support stiffness of star bearing based on the dynamic response under friction excitation. These results provide an understanding of the undesirable dynamic motion in the system, and provide a reference for the design and control of gear systems.