Applications of multi-magnet coupling: switching between vibration isolation and energy harvesting

Purpose Sky-hook stiffness can significantly influence the vibration characteristics of a system across its entire frequency range. This study aims to develop an Adjustable Stiffness Multi-Magnetic Coupling Cantilever (ASMCC) that can be adjusted between vibration reduction and energy-harvesting functions using the sky-hook stiffness. Design/methodology/approach This study investigates the effects of magnet spacing on magnetic force and nonlinear magnetic stiffness within the system. Both simulation and experimental methods are used to explore the vibration characteristics of the system under various magnet configurations. Performance evaluations of isolators and energy harvesters are conducted for specific magnet spacings. Findings The results indicate that introducing multiple magnets redistributes magnetic field, thereby enhancing the isolation and energy-harvesting capabilities of ASMCC. Experimental results show that the ASMCC can reduce the resonance peak by up to 7.7 dB and shift the resonance frequency by 26.4 Hz in vibration reduction mode. In energy-harvesting mode, it achieves a peak output voltage of 89 V, demonstrating the excellent performance of this structure. Originality/value This study presents a versatile device capable of both vibration reduction and energy harvesting, demonstrating strong performance and adaptability across various environments. It provides valuable insights for the design, modeling and optimization of magnetically coupled vibration isolators and energy harvesters.