Zhai Pengcheng

A new theoretical model about shear stress in magnetorheological fluids with small shear deformation

Based on the single-chain structure model of magnetorheological fluids, a formula for the calculation of shear stresses was established. The interaction force of two magnetic particles in an infinite single-chain was deduced using a new theoretical model which is founded on Ampere’ molecular current hypothesis, dipole theory and Ampere’ law. Furthermore, the resultant force on a particle was then deduced by taking into account of the action caused by all the other particles in the single-chain. A predictive formula for shear stresses was made corresponding to the case that MR fluids were sheared by a small angle and the calculating results fit well on the order with the yield stresses of the commercial MR fluids.

A new modified conductivity model for prediction of shear yield stress of electrorheological fluids based on face-center square structure

A new modified conductivity model was established to predict the shear yield stress of electrorheological fluids (ERF). By using a cell equivalent method, the present model can deal with the face-center square structure of ERF. Combining the scheme of the classical conductivity model for the single-chain structure, a new formula for the prediction of the shear yield stress of ERF was set up. The influences of the separation distance of the particles, the volume fraction of the particles and the applied electric field on the shear yield stress were investigated.