A semi-active quasi-zero stiffness vibration isolator based on magnetorheological elastomer with a fast convergence switch control

Quasi-zero stiffness (QZS) isolators have attracted extensive attention due to their high-static–low-dynamic stiffness. The effectiveness of the traditional QZS (T-QZS) isolators to attenuate low-frequency vibration has been extensively studied. The T-QZS isolator, however, cannot usually provide satisfactory vibration mitigation performance under ultra-low frequency excitation. To tackle this challenge, we propose a semi-active QZS isolator featuring magnetorheological elastomer (SAQZS-MRE isolator). The prominent merit of the proposed design is that the applied MRE material can provide varying stiffness and damping to the proposed SAQZS-MRE isolator, making the isolator suitable for vibration isolation under wide-band low-frequency range. The dynamic viscoelasticity properties of the MRE are experimentally characterized, to formulate the dynamic modeling of the SAQZS-MRE isolator. The open-loop vibration isolation characteristics of the SAQZS-MRE isolator are assessed using the harmonic balance method (HBM). Subsequently, two semi-active control strategies including skyhook and fast convergence switch (FCS) are effectively utilized in the proposed SAQZS-MRE isolator to evaluate their closed-loop performance. The results demonstrate that the SAQZS-MRE isolator with FCS control can eliminate the resonance peak and reduce the initial isolation frequency. In the higher frequency range, it can also improve the vibration isolation performance compared with the SAQZS-MRE isolator with passive control.