Design of a high stiffness and hyper-damping vibration isolator based on negative stiffness mechanism

Abstract: In order to isolate direct disturbances exerted on payload and to improve damping properties of an isolation system for purpose of avoiding resonances, a hyper-damping vibration isolator was developed based on a magnetic negative stiffness mechanism. The mechanism consisted of a magnetic negative stiffness spring (MNSS) and two pairs of pre-pressured mechanical springs. MNSS included five magnetic rings axially magnetized, inclined magnetic rings were symmetrically mounted on the base, while a moving ring was constrained by two pre-pressured mechanical springs and was allowed to oscillate along the axial direction. The analytical expressions for magnetic restoring force and magnetic negative stiffness were further deduced according to the current model. By repositioning the stiffness and damping elements of the vibration isolation system, the vibration isolation system was deigned to be a hyper-damping device with the same static stiffness, the same damping and the same mass as those of a typical linear reference system. The impacts of stiffness elements, damping ones of the device and added mass of magnet on the damping, natural frequencies of the designed system and vibration responses of the main system were deeply analyzed. The results showed that the proposed vibration isolation system has high stiffness and hyper damping characteristics and it can effectively suppress vibrations of the main system; the response of the main system converges to that of the linear reference system in a higher frequency range.