An electrorheological (ER) fluid is a colloidal dispersion consisting of semiconducting particles and insulating oil. When an electric field is imposed, its rheological properties vary by showing a characteristic fibrillation, with the strings of the particles oriented along the electric field direction. This particle structuring is caused by the dielectric constant mismatch of the particles and the suspend-ing oil [1]. Due to this mechanism, many typical properties of ER fluids, such as yield phenomenon, viscoelasticity, and drastic increase of viscosity, have been observed. In an electric field, ER fluids solidify in the order of milliseconds, and fluidize under applied deformation, which can destroy the chain structure. Therefore, ER fluids are often regarded as Bingham fluids.
展开▼
