Magnetic Conductivity of MRF and MRE in Inhomogeneous Magnetic Field

This study focuses on the magnetic conductivity of magnetorheological fluids (MRFs) and magnetorheological elastomer (MRE) in variable inhomogeneous magnetic field. It aims to provide a simple method for measuring the permeability of magnetic material and explore the magnetic properties and application advantages of the MRF and MRE. By analyzing the experimental data measured by a magnetic force test device and simulation results, the relative magnetic permeability of MRF and MRE is obtained. The results indicate that the magnetic permeability of MRE can be assuredly enhanced by arranging the magnetic particles in the nonmagnetic medium along the direction of the external driving magnetic field. Additionally, increasing the particle concentration of MRF or MRE is a conventional but quite effective method to improve the permeability of MRF or MRE. Within the scope of this study, the magnetic conductivity of MRF with the same concentration is significantly stronger than that of MRE, and its relative permeability can be higher than 80%. The high flowability of MRF enables the dispersed particles to form chainlike structures along the magnetic lines of flux, which enhances the magnetic induction intensity of the magnetic particles. Considering, a shaping magnetic field with the same distribution of the driving field applied on MRE in the solidification process can unexpectedly improve the magnetic conductivity of MRE. Moreover, compared with the change amplitude of the permeability of MRF, the relative permeability of MRE changes less in different driving magnetic fields due to the constraint of the suspended particles position.