On the prediction of the shear stress of electrorheological suspensions

Several common methods used for calculating the shear stress and shear modulus of electrorheological (ER) suspensions are reviewed. It is found that when the mismatch ratio of the particle dielectric constant to that of the host liquid in an ac electric field or the ratio of the particle conductivity to that of the host fluid in a de electric field is >300, no significant difference exists between the predictions of the various methods employed to-date. However, when Gamma < 300 the several methods give different estimates for the shear yield stress and shear modulus. Empirical equations are given for a simple estimate of the shear yield stress and the shear modulus when Gamma < 300.