Research On The Prediction For Shear Yield Stress Of Electrorheological Fluids

Electrorheological fluids (ERF) consists of a suspension of high dielectric particles in a liquid of low dielectric constant. With the action of the applied electric field, particles interact with each other. The viscosity of ERF increases dramatically and the ERF turns into solid. The solidified ERF can resist the shear stress. When the applied electric field is retreated, the solidified ERF can completely reverse to the original state rapidly. The characteristic of ERF makes it have bright perspective in engineer and mechanism. Based on the principle of electric field and the mechanism of the ERF, according to the experiment phenomenal, dipole model and conductivity model are explained in the paper respectively.In the case of dipole model, it gets the precision distribution of the electric field of the inside and outside of the particle by solving the Laplace equation. The influences of the separation distance of the particles on the shear yield stress are investigated. And the result of the Laplace is also contrasted with the result of the finite element by ansys software.A new modified conductivity model is 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 is 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 are investigated.