Experimentally-Verified Micromechanical Model of MR Gels Based on Planar Current Loop Model

Abstract

As one of the most promising smart materials, magnetorheological (MR) gels have been widely applied in the vibration mitigation of engineering structures. An accurate and effective model for MR gels is of great significance for its in-depth research and engineering application. Existing models for MR materials mainly follow the magnetic dipole theory used for MR fluid, but this theory takes no account of the particle size and, thus, cannot apply to MR gels with a relatively higher volume fraction of particles. In this paper, a micromechanical model for MR gels was proposed and experimentally verified based on the planar current loop model. Firstly, high-performance MR gels were prepared, and basic performance characterizations, including the magnetization property and the sedimentation stability, were carried out. Then the magnetic energy of particles calculated by the magnetic dipole model and the planar current loop model were compared, and the micromechanical model of MR gels was proposed based on the planar current loop model. In the parameter determination process, the data obtained by magnetization tests of the particles were fitted to form the magnetization curve with higher accuracy. Finally, the yield shear stresses of the prepared MR gels were obtained by property tests, and the effectiveness and accuracy of the proposed micromechanical model were verified by comparing the test data with the theoretical values calculated by the proposed model.