A Quasi-Zero Stiffness Nonlinear Absorber Based on Centrifugal Force

A design approach for quasi-zero stiffness (QZS) nonlinear absorbers for rotor system vibration suppression is proposed in this paper. An example of the QZS nonlinear absorber is designed for a single-disc rotor system considering gyroscopic. The nonlinear absorber consists of a rigid mass ring and four circumferentially distributed nonlinear springs, which are coaxially mounted and rotated together with the disc. The equations of motion of the rotor system with the QZS nonlinear absorber are derived by the Lagrange’s equation. According to the motion equations, it shows that the rigid mass ring reveals a negative stiffness due to the centrifugal forces generated by its vibration. The quasi-zero stiffness is realized by combining the positive stiffness provided by the nonlinear springs and the negative stiffness generated by the centrifugal forces. The stability of the rotor system is compromised at high rotational speed due to the speed-dependent negative stiffness provided by the centrifugal force. Thus, the influence of the linear and nonlinear stiffness on vibration suppression and stability of the rotor system are discussed. The present results indicate that increasing the linear stiffness appropriately can enhance the decay rate of the peak vibration and improve the stability of the rotor system.