Stress responses of electrorheological suspensions to stepwise electric fields were measured under different experimental conditions. The stress responses could be expressed by an exponential expression with three modes, modes 0, 1, and 2. The response time of mode 1 multiplied by the shear rate (γ̇${\mathrm{\tau }}_1$) could be roughly scaled by Mason’s number (${\mathit{M}}_{\mathit{n}}$) with the exponent of 0.23, while γ̇${\mathrm{\tau }}_2$ was almost independent of ${\mathit{M}}_{\mathit{n}}$. The aggregation behavior of the particles is discussed in terms of theoretical expectations and our experimental results.

• Received 26 June 1995

DOI:https://doi.org/10.1103/PhysRevE.52.R3325