Yield shear-stress model of magnetorheological fluids

Under an external magnetic field, the particles in a magnetorheological fluids (MRFs) aggregated into chains of dipoles aligned in the direction of the magnetic field so that the MRFs exhibited solidlike mechanical behavior with a yield shear stress. Based on a microscopic analysis and making use of the statistical approach, a micro-to-macroscopic model is proposed for the constitutive behavior of MRFs and the main influencing factors, such as the intensity of magnetic induction, the size of particles, volume fraction of particles, shear strain rate and saturation magnetization. The effects of the influencing factors on the macroscopic behavior of MRFs are investigated and compared with the experimental data. It is found that the proposed model can efficiently describe the mechanical properties of MRFs and can be easily applied to solve practical engineering problems.