Modeling and Analysis of the Electrorheological Fluids (Suspension Flow) with Aligned-Structure Reformation

2012 ◽  
Vol 77 ◽  
pp. 103-107
Author(s):  
Young Wook Seo ◽  
Hyoung Jin Choi ◽  
Yong Sok Seo
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Shear Rate ◽  
Field Strength ◽  
Electrorheological Fluids ◽  
Suspension Flow ◽  
Polarization Model ◽  
Modeling And Analysis ◽  
Proposed Model ◽  
Er Fluids

A new rheological model is applied to the analysis of the behavior of electrorheological (ER) fluids. A comparison of the model’s predictions with experimental data shows that the proposed model correctly predicts the shear stress behavior both quantitatively and qualitatively. The shear stress data for the aligned particles’ structure reformation can be fitted as a function of shear rate with the new model. The yield stress was found to be almost linearly dependent on the field strength, different from the predictions of the polarization model.

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.

COMPARATIVE INVESTIGATIONS ON ER FLUIDS WITH DIFFERENT POLARIZATION MECHANISMS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2751-2757 ◽  
Author(s):  
H. BÖSE ◽  
A. TRENDLER
Keyword(s):  
Shear Stress ◽  
Field Strength ◽  
Electric Fields ◽  
Strong Dependence ◽  
Electric Properties ◽  
Polarization Model ◽  
Polarization Mechanism ◽  
External Conditions ◽  
Ion Conducting ◽  
Er Fluids

The rheological and electric properties of various ER fluids in strong electric fields have been investigated simultaneously. From the measured data the dependences of shear stress and real and imaginary part of the high field permittivity on field strength, temperature and frequency have been derived. One group of ER fluids containing perovskite type particles obeys a polarization mechanism which is attributed to the local displacement of ions in the crystal structure of the particles. The contribution of conduction to ER activity is low and the electric properties of these ER fluids are nearly constant. The increase of shear stress with frequency is in accordance with the polarization model. In contrast, another group of ER fluids containing zeolite or ion conducting polymer particles shows a strong dependence of the complex permittivity on field strength and temperature demonstrating the pronounced nonlinearity of the electric properties. It is assumed that both conduction and polarization contribute to the ER activity in these systems. The relative extent of the contributions changes with external conditions like field strength and temperature.

Computer Simulation of Electrorheological Fluids in the Binary System of Particle Size

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1822-1827
Author(s):  
Yasushige Mori ◽  
Tetsu Tsunamoto ◽  
Hitoshi Nakayama
Keyword(s):  
Computer Simulation ◽  
Particle Size ◽  
Shear Stress ◽  
Fine Particles ◽  
Volume Fraction ◽  
Dielectric Polarization ◽  
Uniform Size ◽  
Polarization Model ◽  
Effect Of Particle Size ◽  
Er Fluids

One of the typical electrorheological (ER) fluids consists of suspension of fine particles in the liquid of low dielectric constant. Particles for ER fluids generally have a size distribution, and some experimental results were reported which showed the effect of particle size on the shear stress of ER fluids. On the other hand, the simulation by dielectric polarization model concluded that the shear stress calculated did not depend on the particle size under the same volume fraction of particles. In order to understand the effect of particle size, the two dimensional computer simulation was carried out for a system containing particles of different size, by using a model similar to that reported by Klingenberg et al. It was found that the shear stress of uniform size system did not depend on the particle size. When small and large particles, with the diameter ratio of 1:2, were mixed in equal numbers of particles, the chain-like clusters consisiting of both sizes of particles were formed. The shear stress and the response time of the binary size system were close to those of uniform size system, if the total volume fraction of particles was kept constant.

Review of the Electrorheological (Er) Effect of Polyurethane-based Er Fluids

2008 ◽  
Vol 18 (2) ◽  
pp. 23956-1-23956-8 ◽  
Author(s):  
S. Schneider ◽  
S. Eibl
Keyword(s):  
Silicone Oil ◽  
Molecular Size ◽  
Electrorheological Fluids ◽  
Chemical Analyses ◽  
Temperature Dependent ◽  
Polarization Model ◽  
Basic Principles ◽  
Dependent Behavior ◽  
Er Fluids ◽  
Temperature Dependent Behavior

Abstract Electrorheological fluids (ERF) change viscosity when an electric field is applied. A special type of ERF consists of polyurethane particles which are doped with Li+ and /or Zn2+ cations and suspended in silicone oil. This article gives an overview of the temperature dependent behavior of the ER effect for these fluids and describes the basic principles how this is explained. Chemical analyses provide information as a basis for a polarization model in several dimensions down to molecular size.

THE ELECTRORHEOLOGICAL FLUIDS WITH HIGH SHEAR STRESS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1065-1070 ◽  
Author(s):  
KUNQUAN LU ◽  
RONG SHEN ◽  
XUEZHAO WANG ◽  
GANG SUN ◽  
WEIJIA WEN
Keyword(s):  
Shear Stress ◽  
Electric Field ◽  
Yield Stress ◽  
High Performance ◽  
Electrorheological Fluids ◽  
Stress Effect ◽  
High Shear ◽  
High Shear Stress ◽  
Effective Factors ◽  
Er Fluids

A series of high performance ER fluids newly manufactured in our laboratory are presented. The yield stress of those ER fluids can reach several tens of kPa, 100 kPa and even 200 kPa, respectively. For understanding the high shear stress effect a model is proposed base on the electric field induced molecular bounding effect. The main effective factors in fabricating the high performance ER are discussed.

DESIGN AND DEVELOPMENT OF FLOW BASED ELECTRO-RHEOLOGICAL DEVICES

1992 ◽  
Vol 06 (15n16) ◽  
pp. 2705-2730 ◽  
Author(s):  
D. A. BROOKS
Keyword(s):  
High Pressure ◽  
Shear Stress ◽  
Shear Rate ◽  
Basic Flow ◽  
Control Surface ◽  
Flow Data ◽  
Operational Systems ◽  
Flow Apparatus ◽  
Er Fluids ◽  
Excess Shear Stress

The foundations for the design of electro-rheological (ER) actuating devices that use Poiseuille flow are laid. Systems of measurement to assess ER fluids are described including a high pressure flow apparatus. This was used to examine alternative valve geometries and fluids. A method is shown for the reduction of basic flow data to excess shear stress and shear rate. Standard actuator arrangements are reviewed before the design of a flying control surface servomechanism is discussed. The evaluation of this validates the methods and indicates that the forces developed are within striking distance of those required for operational systems.

scholarly journals Quasi-Static Rheological Properties of Lithium-Based Magnetorheological Grease under Large Deformation

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2431
Author(s):  
Huixing Wang ◽  
Guang Zhang ◽  
Jiong Wang
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Shear Rate ◽  
Field Strength ◽  
Shear Strain ◽  
Rheological Properties ◽  
Large Deformation ◽  
Magnetic Field Strength ◽  
Maximum Yield ◽  
Cyclic Shear

This paper investigates the quasi-static rheological properties of lithium-based magnetorheological (MR) grease under large deformation. Three types of lithium-based MR grease comprising different mass ratios of carbonyl iron (CI) particles and lithium-based grease were prepared. The dependence of the magneto-induced stress–strain curves for MR grease on CI particles content, shear rate, and shear deformation under quasi-static monotonic shear conditions were tested and discussed. The results demonstrate that the shear rate dependence of the maximum yield stress is significantly weakened by the magnetic field, and this weakening is further enhanced as the CI particles content of MR grease increases. In addition, to evaluate and characterize the behavior of the cyclic shear–stress curves of MR grease under quasi-static condition, cyclic shear tests under different controlled conditions, i.e., CI particles content, shear rate, shear strain amplitude, and magnetic field strength, were conduct and analyzed. The magneto-induced shear stress of MR grease with higher CI particles content shows a sharp decrease during the transition from loading to unloading. Moreover, the experiment results also show that the damping characteristics of MR grease are highly correlated with CI particles content, shear strain, and magnetic field strength.

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.

Low Cost Device for Experimental Tests of Electrorheological Fluids

2014 ◽  
Vol 658 ◽  
pp. 575-580
Author(s):  
Beniamin Vasile Chetran ◽  
Dan Mândru
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Low Cost ◽  
Experimental Tests ◽  
Newtonian Fluids ◽  
Electrorheological Fluids ◽  
The Moment

Electrorheological fluids (ERFs) can change their shear stress and shear rate as a function of the electric field intensity thus, such fluids acts as Newtonian fluids, if no electric field is applied and, become non Newtonian fluids if the presence of an electric field. In the last years, a growth interest is manifested for incorporating smart fluids into structures, as clutches or dumpers. The ERFs shear rate and shear stress must be determined at the moment of designing such mechanical structures. The fluids viscosity is studied by aid of commercially available viscosimeters or rheometers, these do not have the possibility to apply an electric field to the studied fluids. The ER fluids must be studied into specific electric field intensity. This paper presents: a low cost experimental rheometer and experimental results obtained form a study of several commercially available ERFs.

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