Halbach high negative stiffness isolator: Modeling and experiments

Quasi-zero stiffness vibration isolator has received great attention due to the superior low frequency performance. In high static support occasions, a high negative stiffness is desired to counteract the positive stiffness for achieving low-frequency isolation. However, in such aerospace and submarine environments, the mounting space and added weight should be controlled strictly. Therefore, a compact magnetic Halbach high negative stiffness isolator is proposed to improve the low-frequency isolation performance in high static support occasions under the constraint of space and weight in this paper. The magnetic stiffness model is derived to compare the magnetic force of various structures and demonstrate that the proposed isolator has higher negative stiffness without adding extra size and weight. Then, the dynamic equation of the proposed isolator is established and its harmonic balance solution is obtained to investigate the transmissibility for different magnetic arrays. The numerical results have demonstrated the low-frequency isolation performance of the proposed isolator under harmonic and seismic excitations. Moreover, the experimental results of the design prototype show that the onset isolation frequency of the proposed isolator is significantly lower than other magnetic arrays. The adaptability of the proposed isolator for low-frequency isolation under harmonic and random excitations has been explored experimentally. Therefore, it can be demonstrated that the proposed compact Halbach high negative stiffness isolator can contribute to the lightweight design and facilitate the low-frequency vibration isolation for high static support occasions under the constraint of space and weight.