The Effect of Temperature and Electric Field on the Behavior of Electrorheological Fluids (original) (raw)
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A Review On Electrorheological (ER) Fluids And Its Applications
International journal of engineering research and technology, 2012
Electro-rheological fluid (ER) technology is an old ''newcomers'' coming to the market at high speed. Various industries including the automotive industry, production sector, and robotics are full of potential ER fluid applications. Electro-rheological fluid technology has been successfully employed already in various low and high volume applications. A structure based on ER fluids might be the next generation in design for products where power density, accuracy and dynamic performance are the key features. Additionally, for products where is a need to control fluid motion by varying the viscosity, a structure based on ER fluid might be an improvement in functionality and costs. Two aspects of this technology, direct shear mode (used in brakes and clutches) and valve mode (used in dampers) have been studied thoroughly and several applications are already present on the market. Excellent features like fast response, simple interface between electrical power input and mechanical power output, and precise controllability make ER fluid technology attractive for many applications. This paper presents the working principle, methodology to prepare low cost ER fluids, their properties and different applications of ER fluids. The study shows that excellent features like fast response, simple interface between electrical power input and the mechanical power output, and controllability make MRF the next technology of choice for many applications.
Electrorheological Fluids & Flows
In book: 1997 Mc-Graw Hill Yearbook of Science & Technology; Edition: First, Publisher: McGraw Hill, 1997
The electrorheological effect is recognized as the phenomenon of a rapid reversible change in mechanical (rheological) properties of dielectric suspensions of fine particles in a non-conducting oil in the presence of strong electric fields. It was discovered in 1947 by W. Winslow, who observed a change in the effective viscosity (fluidity) of dispersions. An electrorheological fluid consists of a carrier medium (any nonconducting oil) with excellent insulation capability and a filler (particles) with a different dielectric constant dispersed in this medium. Chlorinated paraffin, silicone oil, and mineral oils are the most common carrier fluids. The filler consists of suspended solid particles of 0.1- 100 μmin diameter. The dispersed phase may be either organic material such as microfine powders of soybean casein or starch cellulose or inorganic material such as micro powder mica, silica gel (barium titanate), various polymers such as phenolic resin, or metallic powders. These micro powders are used either untreated or after surface treatment-to improve their dispersability. Although a simple electrorheological fluid such as cornstarch in cooking oil can be easily mixed, it is quite difficult to manufacture an electrorheological fluid which meets commercial expectations.
Dielectric electrorheological fluids: Theory and experiment
Advances in Physics, 2003
Electrorheological (ER) fluids are a class of materials whose rheological properties are controllable by the application of an electric field. A dielectric electrorheological (DER) fluid is the simplest type of ER fluid, in which the material components follow a linear electrostatic response. We review and discuss the progress of the studies on physics of this type of material. A first-principles theory of DER fluids, along with relevant experimental verifications, are presented in some detail. In particular, the properties presented include static equilibrium structure, shear modulus, static yield stress and its variation with applied electric field frequency, and structure-induced dielectric nonlinearity. Contents page 1. Introduction 344 2. Formulation 345 3. Effective dielectric constant evaluation 347 4. Structure in the DER fluid 355 5. Static yield stress of the DER fluid 358 6. Upper bounds of the yield stress and shear modulus 361 7. Comparison with experiments 363 7.1. Mesostructure of the DER fluid 364 7.2. The yield stress of dry glass-oil DER fluids 364 7.3. Structure-induced dielectric nonlinearity 367 8. Summary and discussion 371 Acknowledgements 371 Appendix A. Basis functions 372 A.1. Spherical particles 372 A.2. Spherical shell inclusion 373 Appendix B. Matrix elements of theĜ G operator 374 Appendix C. Proof of an expansion formula 378 Appendix D. Ewald sums 379 References 382
IJERT-A Review On Electrorheological (ER) Fluids And Its Applications
International Journal of Engineering Research and Technology (IJERT), 2012
https://www.ijert.org/a-review-on-electrorheological-er-fluids-and-its-applications https://www.ijert.org/research/a-review-on-electrorheological-er-fluids-and-its-applications-IJERTV1IS10283.pdf Electro-rheological fluid (ER) technology is an old ''newcomers'' coming to the market at high speed. Various industries including the automotive industry, production sector, and robotics are full of potential ER fluid applications. Electro-rheological fluid technology has been successfully employed already in various low and high volume applications. A structure based on ER fluids might be the next generation in design for products where power density, accuracy and dynamic performance are the key features. Additionally, for products where is a need to control fluid motion by varying the viscosity, a structure based on ER fluid might be an improvement in functionality and costs. Two aspects of this technology, direct shear mode (used in brakes and clutches) and valve mode (used in dampers) have been studied thoroughly and several applications are already present on the market. Excellent features like fast response, simple interface between electrical power input and mechanical power output, and precise controllability make ER fluid technology attractive for many applications. This paper presents the working principle, methodology to prepare low cost ER fluids, their properties and different applications of ER fluids. The study shows that excellent features like fast response, simple interface between electrical power input and the mechanical power output, and controllability make MRF the next technology of choice for many applications.
An experimental investigation of the dielectric properties of electrorheological fluids
Smart Materials and Structures, 2009
A home-made electrorheological (ER) fluid, known as ETSERF, has been created with suspension-based powders dispersed in silicone oil. Because of the special structure of their particles, ETSERF suspensions present a complex behavior. In the absence of an electric field, the ETSERF fluid manifests a near-Newtonian behavior, but when an electric field is applied, it exhibits a pseudoplastic behavior with yield stress. The ER effect under DC electric fields has been experimentally investigated using both hydrous and anhydrous ER fluids. The ER properties are strongly dependent on the dielectric properties of ETSERF suspensions, and hydrous ER fluids have a high dielectric constant and a high relaxation frequency which show a strong electrorheological effect. The relationship between the electrorheological effect and the permittivity of ER fluids has also been extensively studied. Experimental results show that the interfacial polarization plays an important role in the electrorheological phenomenon. The ageing of ETSERF fluids was also studied and it was found that the dielectric properties (mainly the dielectric loss tangent) and ER properties are strongly related to the duration of ageing. A fresh ETSERF suspension exhibits high relaxation frequency and high dielectric constant. These results are mainly explained by the effect of interfacial polarizations.
Electrorheological Fluids: Properties, Technology and Modern Applications
IRJET, 2022
Since last three decades, ER fluid has major importance in science, medical and engineering problems, which include vibration reduction and suspension. Electrorheological fluids are smart materials whose rheological properties are controllable through the applications of an external electric field. These rheological properties of ER fluid can be exploited in ERF devices for advanced technological applications. The optimal design of ERF devices requires proper mathematical modeling and basic governing equations. This paper presents the working principles, governing equations and mathematical framework for ER fluids. Also in this paper recent progress of ER devices and their applications have been discussed.
Langmuir, 1998
Simultaneous measurements of viscoelasticity and electrical conductivity are performed to study the dynamic characteristics of structures formed in a highly concentrated electrorheological suspension under a dc electric field of 1.8 kV/mm. Small amplitude oscillatory shear measurements reveal that there is no direct correlation between the elastic modulus and the electrical conductivity of the suspension. A significant increase in conductivity is observed following large amplitude oscillatory shear and, in this case, the linear elastic modulus is also substantially enhanced. These observations are interpreted according to the concept of contact disorder arising from the anisotropic shape of the particulate phase.
A quasi-Bingham model for predicting electrorheological fluid behaviour
Multidiscipline Modeling in Materials and Structures, 2010
This paper presents experimental research on the behaviour of a new electrorheological fluid (ETSERF). The ETSERF is a suspension based on diatomite powders dispersed in silicon oil with a surfactant. A design of experiments is conducted to investigate the effects of electric field strength, particle concentration, surfactant percentage, particle size and shear rate on the efficiency of electro-rheological fluids. The influence of the interactions on shear stresses are analysed by varying all the combinations of the independent variables. The dielectric properties of the ETSERF are investigated in order to explain the interactions between these independent variables. Furthermore, a quantitative relationship between the dynamic shear stresses and the independent variables is developed. The relationship provides a very useful explanation for the contributions of each independent variable to the viscosity and yield stress. A new empirical model is proposed to explain the rheological behaviour of the ER fluids with a shear-thinning behaviour.