A multiband magnetic quasi-zero-stiffness vibration isolator-energy harvester

Most reported vibration-isolation energy-harvesting devices remain constrained by narrow harvesting bandwidths and poor alignment between the energy-harvesting and vibration-isolation regions. To address this issue, this paper proposes a multiband magnetic quasi-zero-stiffness vibration isolator-energy harvester (MB-MQZSI-EH), which enables multiband energy harvesting and dual-functional performance in the middle-frequency band. Quasi-zero stiffness is realized through repulsive magnetic interaction, while multiband harvesting is achieved through the coordinated responses of isolation and absorber PZT cantilevers. An electromechanically coupled model is established using Lagrange’s method and solved by the harmonic balance method. The influences of structural, damping, and electrical parameters are analyzed, and a prototype is fabricated for experimental validation. The results show that the MB-MQZSI-EH achieved three distinct energy-harvesting bands while maintaining effective vibration isolation in the middle-frequency band. The maximum output power reached 1.12 mW, and the low-frequency output power was improved by 26.7% compared with the MQZSI-EH. The isolation onset frequency was reduced to 7.27 Hz, which was 48.2% lower than that of the linear isolator. The harvested energy was also sufficient to power a low-power temperature-humidity sensor. The proposed design offers a compact route for integrating low-frequency vibration suppression with multiband energy conversion.