The flow curves of an electrorheological fluid, made from a suspension of corn starch particles, were examined under repeated applications of shear flow and dc electric field of magnitude of 2kV/mm. It was observed that a sample subjected to this repeated testing would show a considerable increase in field-induced shear stress after several repetitions. For example, at a shear rate of 25s
-1, the shear stress increased after 10 repetitions to 690Pa from an initial value of 370Pa. In addition, after many repetitions there was an increased tendency towards “flow curves” where the shear stress decreased with shear rate. This behaviour was thought to arise from microstructural changes in the material induced by the repeated shearing and activation by electric field.
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