RHEOLOGICAL BEHAVIOR OF ELECTRORHEOLOGICAL FLUIDS

Electrorheological fluids are suspensions of solid particles whose rheological behavior can be strongly modified by the application of an electric field. We analyze the rheograms (stress versus shear rate) of a silica-based fluid with the help of a two spheres model. This model reproduces the hysteresis which is experimentally observed. We emphasize that the previous flow history of the suspension must be known in order to predict its future behavior. A tentative explanation of these observations is proposed on the basis of changes of structure induced by the flow.