Viscoelasticity of an electrorheological fluid using a vertical oscillation rheometer

A vertical oscillation rheometer (VOR), which is designed for the purpose of electrorheological (ER) fluid measurements, is investigated. Linear viscoelastic material functions, such as complex viscosity, complex shear modulus, and loss tangent, are obtained in terms of the geometric parameters of the VOR, the measured force, and the applied strain. The VOR is then calibrated with a Physica rheometer using a corn starch-polybutene/kerosene ER fluid system. The geometry which oscillates vertically is found to be easily constructed and to measure the viscoelastic properties of the ER fluid with a high electric voltage generator. Data from the VOR are Pound to be reliable in a wide range of strain or frequency. (C) 1998 Elsevier Science B.V.