Static shear modulus of electrorheological fluids.
نویسندگان
چکیده
We report measurements of the static shear modulus of electrorheological (ER) fluids consisting of water-wetted silica microspheres in silicone oil. A shear-annealing method, using creep-recovery (CR) cycles under an external electric field, is used to enhance ER properties of the fluid. The shear-annealing method enables the silica spheres in the ER fluid to form better aligned and denser column microstructures. A stable state with elastic shear deformation is obtained after a sufficient number of CR cycles, with an optimal combination of stress duration and shear strength. Static shear modulus is obtained by measuring the elastic deformations at different shear stresses for an electric field frequency from 10 to 1000 Hz. A water-bridge model is proposed to explain the enhanced shear modulus.
منابع مشابه
Simulation Studies of Electrorheological Fluids under Shear, Compression, and Elongation Loading Simulation Studies of Electrorheological Fluids under Shear, Compression, and Elongation Loading
Mechanical properties of electrorheological uids under various dynamical loading conditions have been studied using a computer simulation model. The model assumes electrostatic point-dipole interaction between particles with or without multipolar corrections and the interaction with the base uid due to viscous laminar ow is described with Stokes drag. The mechanical loading is introduced as con...
متن کاملElectro-capillary effects in capillary filling dynamics of electrorheological fluids.
The flow of electrorheological fluids is characterized by an apparent increase in viscosity manifested by the yield stress property of the fluid, which is a function of the applied electric field and the concentration of the suspended solute phase within the dielectric medium. This property of electrorheological fluids generally hinders flow through a capillary if the imposed shear stress is lo...
متن کاملQuasi-static electrorheological properties of hematite/silicone oil suspensions under DC electric fields.
In this work, a modified rheometer has been used to gain information on the "start-up" of the shear flow of an electrorheological (ER) fluid consisting of hematite particles dispersed in silicone oil. The results show that unelectrified suspensions behave essentially as fluids, continuously deforming upon application of shear. However, this behavior changes in the presence of an electric field....
متن کاملSaturated orientational polarization of polar molecules in giant electrorheological fluids.
Many researches on polar-molecular electrorheological (PMER) fluids with giant electrorheological effects were reported in recent years. The particles of PMER fluids (PMER particles) are known to have a dielectric core with high dielectric constant and a shell of polar molecules. Our calculation of local electric fields using the finite element approach shows that the local electric field can c...
متن کاملStructure of electrorheological fluids under an electric field and a shear flow: experiment and computer simulation.
It is known that macroscopic properties of colloidal suspensions are often determined by the microstructure of the particles in the suspensions, depending on the interparticle, Brownian, and hydrodynamic (if any) forces. We take electrorheological (ER) fluids as an example. By using a computer simulation and an experimental approach, we investigate the structure of ER fluids subjected to both a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review. E, Statistical, nonlinear, and soft matter physics
دوره 73 5 Pt 1 شماره
صفحات -
تاریخ انتشار 2006