Modeling and Theoretical Investigation of Nonlinear Torsional Characteristics for Double-Helical Star Gearing System in GTF Gearbox

A improved torsional nonlinear dynamic model of double-helical star gearing system of Geared Turbofan (GTF) aero-engine is established, considering multiple nonlinear parameters and the effect of tool withdrawal groove that connect helical gears on both sides of double-helical gear. The dynamic responses of the system are solved by Runge–Kutta numerical integration method. The results reveal that the double-helical star gearing system exhibits abundant torsional nonlinear behaviors, which were illustrated by the evolution curve of dynamic meshing force and load sharing coefficient under varying rotational speed, gear backflash and width of groove, with either side of helical gear pairs in double-helical gear system are considered and illustrated, respectively, which can be hardly seen in previous research and worth being analyzed for better understanding of undesirable torsional dynamic motion for the double-helical gear system and therefore provide a reference for the design and control of gear system.