Experimentally Verified Hybrid Spatial Structure Micromechanical Model for MR Fluid Prepared by the Drying-Free Process

Abstract

The drying-free preparation of coated magnetic particles has been proven to significantly improve the comprehensive performance and preparation efficiency of magnetorheological (MR) fluid. Due to the magnetic separation technique in the drying-free process, the residual anhydrous ethanol and silicone oil form a Pickering emulsion, whose influence on the properties of MR fluid is ignored in existing mechanical models. In this study, in order to improve the application accuracy of MR fluid and provide methods for further improvement of MR fluid performance, with consideration of the influence of the Pickering emulsion caused by the drying-free process, the tight simple cubic (TSC) structure model and the body-centered cubic (BCC) structure model of MR fluid were proposed based on the mechanism of chain formation of MR fluid and the magnetic dipole theory. To reflect the coexistence and transformation mechanism of these two structures, a distribution probability function was introduced and a hybrid spatial structure model comprised of both TSC and BCC structures was established. The validity and accuracy of the models were verified by the comparison with the experimental data. The proposed hybrid spatial structure micromechanical model considers the influence of Pickering emulsion on the microstructure of MR fluid and can accurately describe the properties of MR fluid prepared by the drying-free process.