Electrorheological (ER) Fluids: A Research Needs Assessment

In 1947, Willis Winslow was awarded a U.S. patent on Methods and Means for Translating Electrical Impulse Into Mechanical Forces. Winslows patent makes use of an electrorheological ER fluid, i.e., one which is transformed from a liquid into a viscoelastic solid upon application of a strong electric field. Based on this gelation effect, a whole new technology has been proposed, providing novel and efficient ways to control fluid flow and power transmission, and to reduce energy loss and damage due to vibration and oscillation. A large number and variety of ER devices have been invented they are described in publications and patents, and many exist as prototype and demonstration devices. ER devices such as shock absorbers, valves, transmissions and fluid couplings are more energy-efficient than hydraulic, mechanical or electromechanical devices which serve the same function. The power needed to operate and ER device is usually very low compared to the power controlled by the device, and its response can be almost instantaneous