Development of a magnetorheological isolator with variable damping and variable stiffness for broadband vibration suppression

Abstract This paper presents the damping and stiffness characteristics of a magnetorheological (MR) isolator with variable damping and variable stiffness (VDVS) for broadband vibration suppression. The MR VDVS isolator is composed of a squeeze-mode MR fluid unit and a shear-mode MR elastomer unit to obtain controllable damping force and stiffness simultaneously. Comparing with the MR fluid device in shear mode and valve mode, the device in squeeze mode can provide large controllable damping force and good energy dissipation ability at both low and high frequency. Based on the conceptual design and finite element simulation of magnetic field, the MR isolator was designed, fabricated and tested. The characteristics of single variable stiffness, single variable damping and combination of both functions were performed by a series of experimental tests. The effects of current, frequency and displacement on the damping and stiffness are analyzed. A new algebraic parametric model was established to predict the hysteretic characteristics of MR isolator. The arctangent function-based model and hysteresis division method-based model were used to capture the hysteresis loops of MR fluid unit and MR elastomer unit, respectively. The results show that the feasibility of the proposed MR VDVS isolator to broadband vibration suppression. Besides, the model can capture the damping and stiffness characteristics of the proposed MR VDVS isolator.