**Papers Published**

- Gavin, H.P. and Hanson, R.D. and Filisko, F.E.,
*Electrorheological dampers, Part I: Analysis and design*, American Society of Mechanical Engineers (Paper) (1996), pp. 7 - .

(last updated on 2007/04/09)**Abstract:**

Electrorheological (ER) materials are suspensions of specialized, micron-sized particles in nonconducting oils. When electric fields are applied to ER materials, they exhibit dramatic changes (within milli-seconds) in material properties. Pre-yield, yielding, and post-yield mechanisms are all influenced by the electric field. Namely, an applied electric field dramatically increases the stiffness and energy dissipation properties of these materials. A previously known cubic equation which describes the flow of fluids with a yield stress through a rectangular duct can be applied to annular flow, provided that certain conditions on the material properties are satisfied. An analytic solution and a uniform approximation to the solution, for the rectangular duct Poiseuille flow case is presented. A numerical method is required to solve the flow in annular geometries. The approximation for rectangular ducts is extended to deal with the annular duct case.**Keywords:**

Particles (particulate matter);Insulating oil;Rheology;Stiffness;Yield stress;Energy dissipation;Electric field effects;Approximation theory;Numerical methods;