| Summary: | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. === Includes bibliographical references (p. 165-168). === In this thesis, I explored the design of a thin variable impedance material using electrorheological (ER) fluid that is intended to be worn by humans. To determine the critical design parameters of this material, the shear response of a sandwich of electrodes separated by ER fluid and several different spacer materials was investigated. After a preliminary test to verify that the shear response is controllable by an applied voltage, a single-axis tensile testing machine was designed and constructed to carry out more accurate testing. Two different ER fluids, homogeneous and heterogeneous were investigated. A model of the material for each fluid along with a general model were developed and the parameters of the models were determined through experiments. The model shows a good fit to the experimental data for the heterogeneous fluid based materials, with prediction errors on the order of 30% for two of the spacer materials. The homogeneous fluid based materials show a strong deviation from the model at OV, but fit well when voltage was applied. Polypropylene as a spacer dramatically reduced or eliminated the ER effect. Some critical design parameters identified include: variation in electrode spacing, spacer material selection, and breakdown levels. === by Douglas Elmer Eastman, IV. === S.M.
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