Simulations of a Dual-Rotor System with Local Rub-Impacts Based on Rigid-Flexible Multi-Body Model

Abstract

The nonlinear dynamical analyses of a dual-rotor system of an aero-engine are investigated with considering local rub-impacts based on rigid-flexible multi-body simulations. The dual-rotor system is set up from a practical aero-engine prototype, which includes an inner shaft (lower-pressure shaft) and an outer shaft (higher-pressure shaft). The two shafts are in internal-external arrangement and connected by six different rolling bearings. Firstly, a rigid-flexible multi-body model of the dual-rotor system with local rub-impacts is established with MSC.Adams. Then, for the rub-impacts happening between the higher-pressure disk and the fixed elastic rod, the rub-impact forces are described as a nonlinear one with piecewise stiffness and a constant friction. At last, the transverse vibrations of the dual-rotor system are simulated. From the obtained frequency spectra and shaft center orbits of given shaft nodes, many of them are composed of multi-frequencies and demonstrate nonlinear motion patterns.