A tunable quasi-zero-stiffness vibration isolator (QZS-VI) with magnetorheological elastomer (MRE)

This paper presents a field-tunable quasi-zero stiffness vibration isolator (QZS-VI), which is beneficial for broadening the frequency bandwidth for low-frequency mitigation. The proposed QZS-VI was constructed by embedding a magnetorheological elastomer (MRE) device into an X-shaped QZS-VI system, which fulfills the tuning capability of vibration isolation. The MRE-based X-shaped system provides tunable negative stiffness, and a vertical spring supports the isolated loadings. The restoring force and stiffness of MRE-based QZS-VI is theoretically investigated, by which the field-induced QZS range (especially a large QZS range in high current values) is analyzed. A dynamic model of MRE-based QZS-VI is established and its isolation performance is numerically studied. The results show that, by controlling the current in the MRE device coil, the system transmissibility can be greatly reduced when the isolation system is under multi-frequency excitation. Furthermore, a prototype of MRE-based QZS-VI is developed, and the verification experiment is conducted. The proposed MRE-based QZS-VI system may be considered as a controllable vibration isolation candidate for random low-frequency excitation.