A new high-static-low-dynamic stiffness vibration isolator based on magnetic negative stiffness mechanism employing variable reluctance stress

To improve the passive control effect on low frequency micro-vibration of structures with high static support stiffness, this paper proposed a high-static-low-dynamics stiffness vibration isolator (HSLDs-VI). This device is equipped with a magnetic negative stiffness mechanism that can provide high magnetic negative stiffness to counteract high static stiffness. The magnetic mechanism is composed of a magnetic spring with negative stiffness (MS-NS) based on variable reluctance stress. It is formed from permanent magnets, a mover, and two stators to create a negative stiffness along the axial direction of the isolation system, which can be connected in parallel with the positive stiffness provided by a mechanical spring. The magnetic force properties of the MS-NS are analyzed with finite element software, and its magnetic stiffness was linearly approximated as a constant near the equilibrium position of the isolator. The transmissibility comparisons of the HSLDs-VI and its corresponding linear vibration isolation systems without MS-NS were analyzed for different masses. The experimental results showed that the HSLDs-VI can be used as a linear isolator to effectively isolate micro-amplitude vibration, reduce the system's natural frequency, and widen the vibration isolation band. At the same time, the damping characteristics of the vibration isolation system near the resonance region were further improved, and the resonance peak was effectively reduced. •A new type of passive isolator with high-static-low-dynamic stiffness is presented.•The mechanism uses variable reluctance stress to provide higher magnetic negative stiffness.•This device can suppress micro-vibration in structures with high static support stiffness.•The theoretical analysis is verified by the finite element analysis and experiments.