Dynamic characteristics of a dual-rotor system subject to foundation excitation

The maneuvering flight of a fighter often causes bearing housing movement of a dual-rotor system of aircraft engines. The displacement in the form of a half-sine pulse is modeled as foundation motion excitation. By numerical integration of the motion differential equations, the dynamic characteristics of the dual-rotor system subject to the foundation and unbalanced excitations are obtained. The vibration behavior during the foundation movement of the low-speed rotor and the high-speed rotor is analyzed, respectively, and the whirl orbits at different natural frequencies are described quantitatively. The restraining effect of bearing damping on dynamic response caused by the foundation movement is also discussed. This paper provides useful insight to clearly understand the action of the foundation movement and unbalanced excitation on the vibration behavior of the dual-rotor system.