A parallel magnetic low stiffness vibration isolator

In order to suppress the low frequency micro-vibration, a parallel magnetic low stiffness isolator consisting of the carrier beam with ends clamped and a magnetic spring was proposed.The magnetic spring was constructed by four permanent magnet pairs,furthermore, those magnets of each magnet pair were assigned in attractive interaction and symmetrically distributed on the surface of the beam. The equivalent current method was employed to establish the model of permanent magnet, and then the magnetic force calculation between two permanent magnets was developed according to Ampere's force law. Finally, the approximate expression of the magnetic force was obtained by curve fitting. The calculation method of equivalent stiffness of the proposed isolation system was acquired based on the analysis of the equivalent stiffness of beam. By ignoring the nonlinear effects of the isolator, the isolation characteristic of the isolator was analyzed by numerical simulation. Results demonstrate that,compared with the traditional vibration isolator, the isolator discussed can effectively isolate the low frequency vibration of the structure. The natural frequency of the system can be reduced. It not only broadens the bandwidth of the isolator, but also improves the damping characteristics of the system; moreover, the peak of resonance is attenuated greatly.