High-frequency disturbance force suppression mechanism of a flywheel equipped with a flexible dynamic vibration absorber

Abstract

Flywheels generate speed-related disturbances and induce micro-vibrations that influence the performance of high-sensitivity instruments on board. This study addresses dynamic modeling and disturbance force suppression of the flywheels due to its inherent characteristic structural modes. The disturbance force transmission of a rotating flywheel due to a unit radial force applied at the rim of the wheel body is reported using the three-dimensional finite element method and frequency response function–based substructuring method. The characteristic structural modes for the radial and axial disturbance forces are identified. The axial deformation–dominated flapping mode and the radial deformation–dominated transverse mode will contribute most to the axial and radial disturbance forces, respectively. A flexible ring structure, which is rested on the arms of the wheel body through independent viscoelastic pads and simultaneously in contact with the inner rim of the wheel body by independent resilient cushion members, is proposed to function as a damped dynamic vibration absorber. The modes of the dynamic vibration absorber and the modes of the flywheel equipped with the dynamic vibration absorber are analyzed. It is shown that the dynamic vibration absorber is effective to suppress both the radial and axial disturbance forces at the characteristic structural modes under different rotational speeds, provided that the loss factor of the complex elastic modulus for the viscoelastic pads is larger than 0.2 and the proportional damping constant for the stiffness matrix is larger than 6 Ns/m. Experimental analyses are conducted on a flywheel with a well-designed dynamic vibration absorber to validate the theoretical findings. Modal tests and disturbance force measurements are carried out for the flywheel with/without the dynamic vibration absorber. It is shown that the identified characteristic structural modes will contribute remarkable peaks for the radial and axial disturbance forces. The proposed dynamic vibration absorber is capable to suppress the high-frequency disturbance forces efficiently under different rotational speeds.