Takayuki Maruyama

Anhydrous Electrorheological Fluid Using Carbonaceous Particulate as Dispersed Phase

An Electrorheological Fluid(ERF) is a suspension essentially composed of fine solid particulates and an electrically insulating oil. Without an electric field, ERF exhibits the rheological properties of a Newtonian fluid whose shear stress is proportional to the shear rate. When an electric field is applied to ERF, the rheological properties of the fluid are instantaneously changed to a Bingham plastic which has the yield stress given by the intercept of the shear stress and the same constant of the proportionality between shear stress and shear rate as the Newtonian viscosity without an electric field. The yield stress rises with increasing voltage and no shear occurs until the shear stress exceeds the yield stress. This phenomenon is called the ER effect which gives rise to the instantaneous change of the apparent viscosity of the fluid.