Frequency dependence of metal-particle/insulating oil electrorheological fluids

Abstract

The frequency dependence of the shear stress of metal-particle/insulating oil electrorheological (ER) fluids under an ac electric field has been studied. The results show that the shear stress of the metal-particle ER fluid under a fixed electric field increases with increasing frequency and then tends to a saturated value at higher frequency. The shear stress at 103 Hz is much larger than that under a dc field. The transition of the shear stress shifts to higher frequency when the conductivity of the fluid is larger. The measurements are consistent with the theoretical model proposed by Davis [J. Appl. Phys. 73, 680 (1993)].© 1995 American Institute of Physics.