Joseph W. Pialet

The Dependence of Shear Stress and Current Density on Temperature and Field for Model Electrorheological Fluids

Electrorheological (ER) fluids have the potential of greatly improving the electronic control of mechanical devices. A lack of theoretical understanding of the ER effect has hindered commercialization of these materials. There has been considerable discussion in the literature on the nature of the ER response1,2,3,4. Performance data have been fit to simple equations by many researchers to gain insight into mechanisms and possible relationships between the variables. This can be particularly difficult since several mechanisms are probably contributing to the observed performance and the dominant mechanism probably varies with field strength, field frequency, temperature and shear rate. Most published work tends to deal with a single relationship for a single fluid. Because each author uses a unique combination of fluid, test device and operating conditions, it is difficult to combine data to get a complete picture. Examining several relationships for the same system under the same conditions may allow identification of additional underlying relationships.