Dynamic characteristics analysis of a coaxial rotor system with shared bearing bore structure

Abstract

The nonlinear dynamic model of a shared bearing bore-coaxial rotor system was established with nonlinear forces of the rolling bearings and squeeze film dampers considered, Cross coupling frequency was found in cross coupling vibration simulation. Numerical studies were conducted to reveal the mechanism of the coupling vibration for the shared bearing bore-coaxial rotor system. The coupling vibration characteristics and influencing factors of the shared bearing bore-coaxial rotor system were studied. The results show that the coupling vibration is featured by cross-excitation phenomenon and orbit which shows a “circle in circle” pattern. Besides, the angular stiffness of the shared bearing bore has great influences on the coupling vibration. However, the radial stiffness has almost no effect on the coupling vibration.