Establishment of a novel solid-liquid integrated model for highly concentrated magnetorheological fluids considering the content of magnetic particles

Abstract The research on magnetorheological fluid has predominantly centered around conventional concentrations (where the mass fraction of ferromagnetic particles typically ranges from 40% to 80%). However, studies exploring high concentrations (such as 90% to 100%) or extreme conditions remain comparatively limited. Existing models struggle to accurately describe the abrupt shear stress transitions observed under such conditions. This paper, through both experimental investigation and theoretical modeling, explores the influence of high-concentration magnetic particles on the microstructure and macroscopic shear properties of MRF. Based on the framework of the Bi-viscous model and the microscopic mechanics model, a corrective term for the particle size distribution is introduced. A solid–liquid integrated (S-LI) model that takes into account the ferromagnetic particle content is proposed. Experimental results demonstrate that the proposed model exhibits a maximum deviation of only 6.2% under varying magnetic fields, accurately capturing the shear yield stress variation in high-concentration MRF. This not only provides experimental evidence for the development and refinement of shear yield stress calculation models for MRF, but also offers a model basis for precise control in magnetorheological dampers from a material perspective.