PRACTICE-RELEVANT ASPECTS OF CONSTRUCTING ER FLUID ACTUATORS

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3243-3255 ◽  
Author(s):  
H. Janocha ◽  
B. Rech ◽  
R. Bölter
Keyword(s):  
Electric Fields ◽  
Electrorheological Fluids ◽  
Flow Mode ◽  
Process Automation ◽  
Rotational Viscometer ◽  
Energy Transducer ◽  
The Individual ◽  
Er Fluids ◽  
The University ◽  
Er Fluid

The flow resistance of electrorheological fluids (ER fluids) can be controlled by applying electric fields. Thus, ER fluids are suitable for the application in actuators, using high-voltage sources for the generation of the field. The behaviour of an ER fluid actuator not only depends on the properties of the individual actuator components (ER fluid, energy transducer and energy source) but especially on their combined efforts as a system. Based on a possible scheme for the design of ER fluid actuators, this paper presents important practice-relevant aspects of a systematic actuator construction. Here the behaviour of a commercial ER suspension is examined and compared to a homogeneous ER fluid without yield point using a rotational viscometer and a flow-mode damper realized at the Laboratory of Process Automation (LPA) of the University of Saarland.

Coating of Polyaniline with an Insulating Polymer to Improve the Power Efficiency of Electrorheological Fluids

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1931-1939 ◽  
Author(s):  
J. Akhavan ◽  
K. Slack ◽  
V. Wise ◽  
H. Block
Keyword(s):  
Power Efficiency ◽  
Electrorheological Fluids ◽  
Emeraldine Base ◽  
Heavy Duty ◽  
Base Form ◽  
Static Yield ◽  
High Fields ◽  
Er Fluids ◽  
Er Fluid ◽  
A Current

Currents drawn under high fields often present practical limitations to electrorheological (ER) fluids usefulness. For heavy-duty applications where large torques have to be transmitted, the power consumption of a ER fluid can be considerable, and for such uses a current density of ~100μ A cm -2 is often taken as a practical upper limit. This investigation was conducted into designing a fluid which has little extraneous conductance and therefore would demand less current. Selected semi-conducting polymers provide effective substrates for ER fluids. Such polymers are soft insoluble powdery materials with densities similar to dispersing agents used in ER formulations. Polyaniline is a semi-conducting polymer and can be used as an effective ER substrate in its emeraldine base form. In order to provide an effective ER fluid which requires less current polyaniline was coated with an insulating polymer. The conditions for coating was established for lauryl and methyl methacrylate. Results from static yield measurements indicate that ER fluids containing coated polyaniline required less current than uncoated polyaniline i.e. 0.5μ A cm -2. The generic type of coating was also found to be important.

The Place of Dielectric Spectroscopy in Probing Electrorheology

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1829-1836 ◽  
Author(s):  
S. Kyvelidis ◽  
G. M. Maistros ◽  
P. Rattray ◽  
H. Block ◽  
J. Akhavan ◽  
...  
Keyword(s):  
Electric Fields ◽  
Working Conditions ◽  
High Shear ◽  
Empirical Correlations ◽  
Electrical Parameters ◽  
Shear Rates ◽  
Uniform Shear ◽  
High Shear Rates ◽  
Er Fluids ◽  
Er Fluid

The measurement of the dielectric spectra of PAnQR based ER fluids under shear and electric fields is discussed and results presented. Data in which either but not both shear or electric fields are present are submitted to analysis in terms of known theories. For flow alone, that analysis provides information on the attenuation of polarization by the uniform shear fields whilst the polarization of quiescent fluids by electric fields may lead to estimates of particles packing within the columns. Permittivity data when both fields are acting is presented, but in the absence of suitable theory, not modelled quantitatively. Empirical correlations are discussed and the conclusion drawn that fibrillation is readily suppressed by even moderate shear rates, although long range dipolar forces still persist to high shear rates. The dc conductance of these fluids have also been measured. This together with permittivity data under ER fluid working conditions has importance in establishing the electrical parameters for any ER fluid.

BINGHAM AND RESPONSE CHARACTERISTICS OF ER FLUIDS IN SHEAR AND FLOW MODES

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1017-1024 ◽  
Author(s):  
H. G. LEE ◽  
S. B. CHOI ◽  
S. S. HAN ◽  
J. H. KIM ◽  
M. S. SUH
Keyword(s):  
Electric Fields ◽  
Flow Mode ◽  
Shear Mode ◽  
Damping Force ◽  
Response Characteristics ◽  
Operating Modes ◽  
Field Dependent ◽  
Different Temperatures ◽  
Er Damper ◽  
Er Fluid

This paper presents field-dependent Bingham and response characteristics of ER fluid under shear and flow modes. Two different types of electroviscometers are designed and manufactured for the shear mode and flow mode, respectively. An ER fluid consisting of soluble chemical starches (particles) and silicon oil is made and its field-dependent yield stress is experimentally distilled at two different temperatures using the electroviscometers. Time responses of the ER fluid to step electric fields are also evaluated under two operating modes. In addition, a cylindrical ER damper, which is operated under the flow mode, is adopted and its measured damping force is compared with predicted one obtained from Bingham model of the shear and flow mode, respectively.

Surface Feedback for Virtual Environment Systems Using Electrorheological Fluids

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3011-3018 ◽  
Author(s):  
P.M. Taylor ◽  
A. Hosseini-Sianaki ◽  
C.J. Varley
Keyword(s):  
Experimental Study ◽  
Information System ◽  
Virtual Environment ◽  
Electric Fields ◽  
Electrorheological Fluids ◽  
Different Types ◽  
Flexible Designs ◽  
Er Fluids ◽  
The Given

A tactile array system, when incorporated in an information system, provides a means of conveying tactile data to the user. Such arrays have many applications including simulators for training purposes and Braille systems for the blind. The use of ER fluids in these systems would provide an inexpensive alternative to the existing technologies because of the simple and flexible designs. An experimental study has been conducted which involves a simple 5×5 array of tactels, each tactel being independently energised in order to configure a variety of shapes. A series of tests are carried out on two different types of ER fluids under a range of electric fields and sensor speeds. The results show that for the given tactel spacing, the programmed shapes are easily detected for all conditions and are directly comparable to similar tests undertaken on a solid shape.

Investigations on Zeolite-Based ER Fluids Supported by Experimental Design

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1878-1885 ◽  
Author(s):  
H. Böse
Keyword(s):  
Experimental Design ◽  
Cation Exchange ◽  
Electric Fields ◽  
Silicone Oil ◽  
Fluid Temperature ◽  
Zeolite A ◽  
Oil Viscosity ◽  
Cation Composition ◽  
Er Fluids ◽  
Er Fluid

The application of experimental design for determining the influence of various parameters on rheological properties of electrorheological (ER) fluids is demonstrated. Such statistical methods allow the quantitative determination of parameter effects even in the presence of considerable property fluctuations of the ER fluid as well as the calculation of interactions between the parameter effects. They thus provide a powerful optimization tool. Investigations have been performed on ER fluids containing particles of zeolite A in silicone oil. The influence of zeolite content, oil viscosity, particle size, cation composition and ER fluid temperature on the viscosity of ER fluids with and without electric field has been studied. In addition to the main effects of the parameters interactions between them also play a considerable role. The ratio of ER fluid viscosities with and without field, respectively, decreases with rising oil viscosity and increases with temperature. The larger value of the ratio for ER fluids with smaller particles is referred to different particle structures. Results of parameter effects on viscosity of the ER fluid in electric fields depend on the shear rate. Cation exchange of sodium to potassium has only a minor influence on ER activity. This result is compared with cation exchange with calcium, by which ER activity is drastically diminished. The loss of activity can be related to the occupation of different cation sites in zeolite A.

Sound Transmission Loss in Electrorheological Fluids Under DC Voltage

2000 ◽  
Author(s):  
Marek L. Szary ◽  
Maciej Noras
Keyword(s):  
Shear Stress ◽  
Sound Pressure ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Electrorheological Fluids ◽  
Sound Transmission Loss ◽  
Dc Voltage ◽  
College Of Engineering ◽  
Er Fluids ◽  
Er Fluid

Abstract Extensive investigations of sound transmission loss (STL) in electrorheological (ER) fluids were conducted in the Acoustics Laboratory in the College of Engineering, Southern Illinois University Carbondale. The STL was investigated for different kinds of ER suspensions in frequency ranges from 100 Hz to 2kHz. Applied DC voltage to the different electrodes allowed normal and shear stress to develop in the ER fluid respectively. The electric field density was variable. Sound transmission loss was obtained by measurement of the sound pressure level in front of and behind the sample. Under both normal and shear stress in ER fluid, STL decreases with increasing stress. Those properties of ER fluids can be useful in noise and vibration control applications.

ER-FLUID RHEOLOGICAL PROPERTIES IN TERMS OF THE MULTIPARTICLE MODEL OF A COMPOSITE

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2676-2682
Author(s):  
YU. G. YANOVSKY ◽  
V. E. ZGAEVSKII ◽  
Z. P. SHULMAN ◽  
E. V. KOROBKO
Keyword(s):  
Electric Field ◽  
Rheological Properties ◽  
Three Dimensional ◽  
Microscopic Theory ◽  
Electrorheological Fluids ◽  
Mathematical Apparatus ◽  
Couple Interaction ◽  
Er Fluids ◽  
Er Fluid ◽  
Electrorheological Properties

The three-dimensional multi-particle well-ordered model could be considered as an analogy to a crystal body. We use this model for describing rheological properties of concentrated electrorheological fluids (ER fluids). According to this model, the particles of the suspension take their places at sites of a grid with specified type of symmetry and then an electric field is applied to the fluid. Taking into account hydrodynamic couple interaction of particles and forces of electrostatic interaction of particles polarized under the action of an external electric field and employing the mathematical apparatus of the microscopic theory of crystals, we construct the basic relationships for describing viscoelastic electrorheological properties of ER fluids.

TRANSIENT BEHAVIOR OF THE MICROSTRUCTURE OF ELECTRORHEOLOGICAL FLUIDS IN SHEAR FLOW MODE

2001 ◽  
Vol 15 (06n07) ◽  
pp. 695-703 ◽  
Author(s):  
S. L. VIEIRA ◽  
M. NAKANO ◽  
S. HENLEY ◽  
F. E. FILISKO ◽  
L. B. POMPEO NETO ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Flow ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Transient Behavior ◽  
Electrorheological Fluids ◽  
Flow Mode ◽  
Er Fluid

It was reported that under the simultaneous stimulus of an electric field and shear, the particles in an ER fluid form lamellar formations in the direction of shear (adhered to one of the electrodes) which may be responsible for the ER activity more than the strength of the chains. In this way, it would be expected that the shear stress should change consistently with the morphology of the formations. In this work we studied the effect of shearing time, electric field strength and shear rate on the shear stress. We suggest that changes on shear stress with time are due to changes of the morphology of the lamellar formations.

Dynamic Fatigue Characteristics of Electrorheological Fluids: Experimental Results

2006 ◽  
Vol 324-325 ◽  
pp. 177-180 ◽  
Author(s):  
Seung Bok Choi ◽  
Kum Gil Sung
Keyword(s):  
Yield Stress ◽  
Electrorheological Fluids ◽  
Flow Mode ◽  
Electric Voltage ◽  
Operating Cycle ◽  
Field Dependent ◽  
Flow Motion ◽  
Fatigue Characteristics ◽  
Er Fluid ◽  
Dynamic Fatigue

In this study, the dynamic fatigue characteristics of chemical starch-based ER fluid are experimentally investigated. A flow mode type apparatus is manufactured to activate the flow motion of the ER fluid. After evaluating the field-dependent Bingham property, three important dynamic fatigue characteristics; yield stress, current density and response time of the ER fluid are investigated as a function of the operating cycle. The dynamic operation for the flow motions is undertaken up to one million cycles and electric voltage is applied to the electrodes. In addition, the change of the particles of the ER fluid is microscopically observed to advocate the variation of the yield stress.

scholarly journals Electrorheological Fluids of GO/Graphene-Based Nanoplates

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 311
Author(s):  
Yudong Wang ◽  
Jinhua Yuan ◽  
Xiaopeng Zhao ◽  
Jianbo Yin
Keyword(s):  
Electric Fields ◽  
Smart Materials ◽  
High Performance ◽  
Short Circuit ◽  
Dielectric Spectrum ◽  
Electrorheological Fluids ◽  
Dispersed Phase ◽  
External Electric Fields ◽  
Anisotropic Morphology ◽  
Er Fluids

Due to their unique anisotropic morphology and properties, graphene-based materials have received extensive attention in the field of smart materials. Recent studies show that graphene-based materials have potential application as a dispersed phase to develop high-performance electrorheological (ER) fluids, a kind of smart suspension whose viscosity and viscoelastic properties can be adjusted by external electric fields. However, pure graphene is not suitable for use as the dispersed phase of ER fluids due to the electric short circuit caused by its high electrical conductivity under electric fields. However, graphene oxide (GO) and graphene-based composites are suitable for use as the dispersed phase of ER fluids and show significantly enhanced property. In this review, we look critically at the latest developments of ER fluids based on GO and graphene-based composites, including their preparation, electrically tunable ER property, and dispersed stability. The mechanism behind enhanced ER property is discussed according to dielectric spectrum analysis. Finally, we also propose the remaining challenges and possible developments for the future outlook in this field.

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