An analytical model for magnetorheological fluids

Two- and three-dimensional analytical models for the yield stress of magnet orheological (MR) fluids as a function of magnetic field and total volume f raction of particles are developed, which are in accord with experimental d ata. important factors are the packing density of the particles in the aggr egates, their magnetization saturation and the enhanced field between the p articles. Our calculations indicate that the torsional force components due to the anisotropic magnetizability of the entire MR suspension may contrib ute up to 20% of the resultant shear force. Further, when the particles are completely saturated the yield stress is proportional to the square of the saturation magnetization.