Experimental investigation on dynamic characteristics of rotor system subject to foundation vibration

In order to meet the requirements of dynamic design for rotor system of aero-engine, the effects of the foundation vibration, especially in exciting amplitudes and frequencies, on the transverse vibration characteristics of a rotor system were investigated experimentally. The results show that the impact of the foundation vibration on the dynamics characteristics possesses an orthogonality in direction, suggesting that the vibration of the foundation in horizontal can merely affect the horizontal response of the rotor. Otherwise, coupled vibration happened between the rotor and foundation. Both of amplitudes and frequencies of the foundation excitation have significant influence on the behavior of the rotor including shape and magnitude of orbits. The amplitude of the rotor increases linearly with the amplitude increment of foundation while it increases quadratically as the frequency of the foundation vibration grows. As a result, the amplitude ratio can most reach 4. Considering the intricate changes in shape and sharp augment in rotor amplitude resulting from large foundation vibration, the influence of foundation must be taken into account in the dynamic design for aero-engine rotor system, so as to make sure that the vibration of the rotor stays at a low level.