Dynamic properties of an ER fluid under shear and flow modes

This paper presents the field-dependent Bingham and response characteristics of an electro-rheological(ER) fluid under shear and flow modes. Two different types of electroviscometers are designed and manufactured for the shear mode and the flow mode, respectively. An ER fluid consisting of soluble chemical starches (particles) and silicone oil is made and its field-dependent yield stress is experimentally distilled at two different temperatures using the electroviscometers. Time responses of the ER fluid to step electric fields are also evaluated under two operating modes. A single-disc type ER clutch, which is operated under the shear mode, is adopted and its measured transmitted torque is compared with the predicted ones from Bingham models obtained at two different operating modes. In addition. the field-dependent damping force of a cylindrical ER damper, which is operated under the flow mode is measured and compared with the predicted ones from Bingham models obtained under both the shear and the flow modes. (C) 2002 Elsevier Science Ltd. All rights reserved.