Theodore G. Duclos

CONTROLLABLE FLUIDS: THE TEMPERATURE DEPENDENCE OF POST-YIELD PROPERTIES

This paper represents the first detailed description of the affect of temperature on the properties exhibited by state-of-the-art electrorheological (ER) and magnetorheological (MR) fluids. In particular, shear stress versus shear strain rate curves, dynamic and static yield stress values, zero-field viscosity data, and current density measurements are discussed. Specific comments concerning the stability of both mechanical and electrical properties over broad temperature ranges are provided. Finally, insight into the advantages associated with using electrorheological and magnetorheological fluids in a controllable device is provided.

Electrorheological Fluids — Materials and Applications

Ask an engineer if a material can be changed from a liquid to a solid and the reply will likely be: “Of course, water can be frozen to make ice.” Ask if the solidification might be accomplished at constant temperature or pressure and there will probably be no response. If you probe further and see if the engineer can suggest a way to control the shear stress vs. shear rate behavior, a continued look of bewilderment will be the response.