A quasi-zero stiffness dual-functional device based on magnet-piezoelectric cantilever beams for vibration isolation and energy harvesting

To address the challenges of low-frequency vibration isolation and energy harvesting in engineering environments, this study proposes a magnet-piezoelectric cantilever beam-based dual-functional quasi-zero stiffness vibration isolation and energy harvesting device (MQZSI-EH). The magnetic repulsive force between the cantilever-tip magnet and the platform-mounted magnet induces quasi-zero stiffness (QZS) characteristics, thereby reducing the isolation onset frequency while simultaneously enhancing the cantilever bending response under low-frequency excitation to improve energy harvesting performance. An electromechanical coupling model is established to investigate the effects of magnet spacing and cantilever length on the stiffness characteristics. The harmonic balance method is employed to analyze the influence of key parameters on vibration isolation and energy harvesting performance. Experimental results validate the theoretical predictions. Compared with a conventional linear isolator, the proposed device achieves an isolation onset frequency of approximately 7.45 Hz, representing a reduction of about 50%, along with a significant decrease in peak force transmissibility. Moreover, a maximum output power of approximately 0.6 mW is achieved under low-frequency excitation, which is about 350% higher than that of a cantilever-beam harvester. This study provides a new approach for low-frequency vibration isolation and energy harvesting.