EXPERIMENTAL MEASUREMENTS OF THE DYNAMIC TORQUE RESPONSE OF AN ELECTRORHEOLOGICAL FLUID IN THE SHEAR MODE

Abstract

Experimental measurements of the time response of an electrorheological fluid in a high natural frequency Couette type of rheometer system are reported for both step and variable frequency, DC biased small amplitude sine wave voltage excitation. The effects of both the speed of the rotating element of the rheometer and the magnitude of its voltage relative to the stationary element as well as the fluid temperature level are presented for time, frequency and steady domains. For a given DC voltage level and over the range of tests carried out, the fluid response time improves considerably with both increase in the temperature and speed, whereas the effect on the magnitude of the steady state ER torque value is marginal. Very encouraging results are obtained when the performance of the fluid with regard to the step tests are compared with results of transformed data taken from a larger and more practical clutch system and those acquired from the same fluid but in the flow mode valve arrangement.