Lever-type quasi-zero stiffness vibration isolator with magnetic spring

• A lever-type quasi-zero stiffness (QZS) vibration isolator is modeled and analyzed • Vibration isolation performance improves with the lever ratio and tip mass • Asymmetric permanent magnets produce beneficial negative and hardening stiffness • Eddy current damping benefits the vibration isolation of QZS vibration isolators Unlike the tuning of the vibration isolation band through stiffness and geometric parameters in traditional quasi-zero stiffness (QZS) vibration isolators (VIs), this study presents a lever-type QZS vibration isolator (L-QZS-VI) to improve the vibration isolation performance. The QZS characteristic is realized with a magnetic spring. Eddy current damping (ECD) is used to eliminate the jump phenomenon and improve the vibration isolation performance. A theoretical model of L-QZS-VI with ECD is developed and the corresponding governing equation is obtained using the Lagrange equation. The displacement transmissibility is derived using the harmonic balance method. The effects of the tip mass of the lever, lever ratio, nonlinear stiffness of the magnetic spring and excitation amplitude on the vibration isolation performance of the L-QZS-VI are analyzed numerically and experimentally. The vibration isolation performance can be largely improved by tuning the lever ratio, tip mass of the lever, and nonlinear stiffness of the magnetic spring. The ECD can produce tunable damping to further improve the vibration suppression performance in the resonance region. This study provides a guideline to design, model, and optimize L-QZS-VI.