INTERACTION BETWEEN PARTICLES AND PARTICLE CHAINS IN ELECTRORHEOLOGICAL FLUIDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1033-1041 ◽  
Author(s):  
GUO-QING GU ◽  
P. M. HUI
Keyword(s):  
Electric Field ◽  
Standard Form ◽  
Approximate Expression ◽  
Electrostatic Energy ◽  
Granular System ◽  
Analytic Expressions ◽  
Rigorous Framework ◽  
A Chain ◽  
Er Fluids ◽  
Particle Chains

The electric potential in a granular system consisting of spherical inclusions in the presence of an external applied electric field is studied in detail within the framework of the Rayleigh identity. The effects of induced charges on the inclusions are taken into account explicitly. The method, in principle, includes the effects of all multipoles. The method is applied to study the interaction between two inclusions. The standard form of interaction between inclusions widely used in studying ER fluids is recovered as an approximation of our general approach. We then apply the method to a chain of inclusions. Analytic expressions for the electrostatic energy per inclusion and the electric field are obtained for the case in which the chain is parallel to the applied field. Our result reduces to the form used in the literature when appropriate approximation is taken. The method is further extended to study the interaction between chains of inclusions. An approximate expression is obtained for the force between two chains of inclusions. Our approach provides a rigorous framework for determining the interaction between inclusions and chains of inclusions to arbitrary accuracy.

Simulation Studies on Structure-Force Dynamic Coupling of Electrorheological Fluids in a Poiseuille Flow Field

2012 ◽  
Vol 443-444 ◽  
pp. 796-801 ◽  
Author(s):  
Shi Sha Zhu ◽  
Bin Tang ◽  
Li Juan Qu ◽  
Wei Yuan ◽  
Quan Fu Zhang
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Pressure Gradient ◽  
Poiseuille Flow ◽  
Structural Changes ◽  
Three Dimensional ◽  
Dynamic Coupling ◽  
A Chain ◽  
Electric Field Force ◽  
Er Fluids

Based on the modified Maxwell-Wagner model, the molecular dynamics method is applied to simulate the three-dimensional structural changes of the electrorheological (ER) fluids in an electric field and a poiseuille flow field. And it is analyzed that the structure-force dynamic coupling is characterized significantly by capture effect. The simulation results show that: when the electric field is applied, a chain network will capture the upstream particles in the flow field causing the local electric field force changed. Eventually a body-centered tetrahedron (BCT) is formed, and the structure-force dynamic coupling characterizes significantly. For an ER fluids in a electric field, there exist a threshold of pressure gradient. Its significance of structure-force dynamic coupling is related to electric field intensity, pressure gradient or flow velocity.

PRELIMINARY OPTICAL STUDY ON ER FLUIDS

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2921-2933 ◽  
Author(s):  
L. W. ZHOU ◽  
J. F. YE ◽  
R. B. TAO ◽  
Y. TANG ◽  
J. F. PENG ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Electric Fields ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Optical Response ◽  
Optical Study ◽  
Solid States ◽  
Linear And Nonlinear ◽  
Er Fluids

Linear and nonlinear optical study on electrorheological (ER) fluids is reported. The ER fluids under the investigation were glass beads, zeolite and ferroelectrics. The linear optical response of some ER fluids showed sharp changes near critical electric fields. An enhancement of electric field induced second harmonic generations (EFISH) was observed as the function of E2, where E is the external electric field. The said enhancement is considered to be corresponding to a modulation of the material's refractive index associated with the electric field induced polarization of the delocalized electrons. The enhanced nonlinear optical response on the transition between liquid and solid states can be related to the phase transition in ER fluids.

scholarly journals THE EFFECT OF ELECTRIC FIELD DIRECTION ON THE-SHEAR STRESS OF ER FLUIDS

1996 ◽  
Vol 45 (4) ◽  
pp. 640
Author(s):  
WANG ZUO-WEI ◽  
LIN ZHI-FANG ◽  
TAO RUI-BAO
Keyword(s):  
Shear Stress ◽  
Electric Field ◽  
Field Direction ◽  
Electric Field Direction ◽  
Er Fluids

MOLECULAR ORIENTATION AND ELECTROHYDRODYNAMIC FLOW IN HOMOGENEOUS ER FLUIDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 973-979 ◽  
Author(s):  
HIROKI IWATSUKI ◽  
NAOTO GOHKO ◽  
HIROSHI KIMURA ◽  
YUICHI MASUBUCHI ◽  
JUN-ICHI TAKIMOTO ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Molecular Orientation ◽  
Liquid Crystalline ◽  
Polypropylene Glycol ◽  
Homogeneous Fluid ◽  
Immiscible Liquids ◽  
Electrohydrodynamic Flow ◽  
Er Fluids ◽  
Er Fluid

Homogeneous ER fluid is an ER fluid which consists of a homogeneous fluid only; it is neither a suspension nor a blend of immiscible liquids. Various liquid crystals are typical examples of homogeneous ER fluids. Recently, we have found that urethane-modified polypropylene glycol (UPPG) is one of the very few examples of homogeneous ER fluids which show no liquid crystalline order. In order to clarify the mechanism of the ER effect in this fluid, we have studied, in this paper, electrohydrodynamic flow under shear and electric field.

THE FREQUENCY DEPENDENCE AND NON-LINEAR DIELECTRIC PROPERTY OF ER FLUID

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3073-3080 ◽  
Author(s):  
KUNQUAN LU ◽  
WEIJIA WEN ◽  
CHENXI LI
Keyword(s):  
Dielectric Property ◽  
Field Strength ◽  
Electric Field ◽  
Frequency Dependence ◽  
Threshold Value ◽  
Shear Stresses ◽  
Linear Behavior ◽  
Non Linear ◽  
Er Fluids ◽  
Er Fluid

The frequency dependence of the shear stress in ac field and the non-linear dielectric property of ER fluid have been studied. We find that the shear stresses of some water-free ER fluids increase monotonously with the frequency and tend to reach saturated values at high frequency. The measurements on KNbO 3/silicone ER fluid show that the shear stresses under 103 Hz frequency a.c. field are several times or even an order larger than that under d.c. field for the same field strength. The studies of non-linear dielectric properties of ER fluids show that the permittivity of ER fluid increases linearly with increasing field strength when the electric field exceeds a threshold value E 1 and tends to a saturated constant beyond a high field strength E 2. Correspondingly the current density follows linear behavior no longer in the region between E 1 and E 2. A model based on the rearrangement of the particles under the electric field. which causes the variation of the dielectric property of the ER fluid, is proposed and the analysis is consistent with the measured results.

Deformation of metallic liquid drop by electric field for contacts in molecular–organic electronics

2009 ◽  
Vol 465 (2106) ◽  
pp. 1799-1808 ◽  
Author(s):  
M. Bag ◽  
D. Gupta ◽  
N. Arun ◽  
K.S. Narayan
Keyword(s):  
Solid State ◽  
Surface Energy ◽  
Electric Field ◽  
Linear Response ◽  
Liquid Drop ◽  
Electrostatic Energy ◽  
Critical Voltage ◽  
Metallic Liquid ◽  
Linear Response Regime ◽  
Polymer Electronics

We study and use the behaviour of a metallic liquid drop in the presence of an external electric field (EF). The droplet profile is governed by the stabilizing surface energy and the destabilizing electrostatic energy, with a critical voltage beyond which the droplet becomes unstable. We explore the EF-induced behaviour of low melting temperature alloy in the liquid state and observe that the droplet modifications in the linear response regime can be retained upon cooling the drop to the solid state. We demonstrate that this procedure can be used as an electrode with precise dimensions for applications in molecular and polymer electronics.

ELECTRIC-FIELD-INDUCED PHASE SEPARATION IN ELECTRORHEOLOGICAL FLUIDS

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2811-2822 ◽  
Author(s):  
XIN-LU TANG ◽  
KE-QIN ZHU ◽  
E. GUAN ◽  
XIAO-PING WU
Keyword(s):  
Phase Separation ◽  
Electric Field ◽  
Strong Electric Field ◽  
Processing System ◽  
Video Camera ◽  
Two Dimensional ◽  
Critical Fields ◽  
Computer Image Processing ◽  
Er Fluids ◽  
Er Fluid

The phase separation into a high-density and a low-density phase, which occurs after a strong electric field is applied to an ER fluids, is demonstrated in terms of the Coulomb interaction energy of the system. The phase separation is manifested by two-dimensional pattern observed in the field direction by means of a pair of transparent glass (TG) electrodes. The development of phase separation with an increasing field is recorded by a computer image processing system consisting of a CCD video camera. The patterns are irregular and their characteristic sizes are determined by two-dimensional auto-correlation approach. The dependency of those patterns on external electric field is analyzed based on statistical methods. Two critical fields are presented to characterize the electric-field-induced phase separation process in the ER fluid.

ER EFFECT OF LOW MOLECULAR LIQUID CRYSTAL ON ONE-SIDED PATTERNED ELECTRODES

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4988-4995 ◽  
Author(s):  
TAKEHITO KIKUCHI ◽  
AKIO INOUE ◽  
JUNJI FURUSHO ◽  
RYOHEI KAWAMUKI
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Short Circuit ◽  
Flow Characteristics ◽  
Electrode System ◽  
Processing Technologies ◽  
Pattern Type ◽  
Molecular Liquid ◽  
Er Fluids ◽  
Different Characteristics

Several kinds of ER fluids (ERF) have been developed and have been applied to some mechatronics devices and processing technologies. In many conventional applications of ERFs, these devices consist of bilateral electrodes to apply electric field in ERF. However, the electric field of several kV/mm may be necessary to generate an ER effect sufficiently for practical purposes. The gap between a pair of electrodes should be, therefore, maintained narrowly and exactly for fears of short-circuit. At the same time, this electrode system also requires an interconnection on driving parts. To improve these disadvantages, we proposed "one-sided patterned electrode" (OSPE) systems in previous works. In this report, we confirmed the flow characteristics of low molecular liquid crystal (LMLC) on OSPE. Next, we also confirmed the different characteristics depending on the pattern type. Depending on results of electro-static analysis, we conclude that such a difference may results from the directors of LC molecules derived by electric field.

Velocities of Starch Particles in ER Fluids Measured with Laser Speckle

2011 ◽  
Vol 287-290 ◽  
pp. 2781-2784
Author(s):  
Ji Jun Fan ◽  
Nan Hui Yu
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Ccd Camera ◽  
Laser Speckle ◽  
Time Intervals ◽  
Sample Concentration ◽  
Speckle Patterns ◽  
The Mean ◽  
Er Fluids ◽  
Short Time

In this paper, the principle of measuring infinitesimal displacement by laser speckle is proposed to measure the velocities of particles in ER fluids. It is verified that speckles can be formed by illuminating laser beam on the starch ER fluids. The speckle patterns was recorded with high speed CCD camera, and the speckle patterns sequences with short time intervals was obtained by intercepting laser speckle video. Displacements parallel to the direction of electric field and that perpendicular to the direction of electric field were obtained by processing the two consecutive speckle patterns. The experimental results showed that the velocities of particles decreased oscillatorily with time. There is a critical electric field and a critical sample concentration, when lower than this critical electric field (concentration), the mean particle velocity increased; otherwise, it decreased.

CONDUCTIVITY AND FORCE BETWEEN PARTICLES IN A MODEL ELECTRORHEOLOGICAL FLUID I: CONDUCTIVITY

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3315-3325 ◽  
Author(s):  
C.W. WU ◽  
Y. CHEN ◽  
X. TANG ◽  
H. CONRAD
Keyword(s):  
Electric Field ◽  
Glass Bead ◽  
Silicone Oil ◽  
Field Enhancement ◽  
Water Film ◽  
Electrorheological Fluid ◽  
Large Strains ◽  
Electric Field Enhancement ◽  
A Chain ◽  
Water Contents

The conductivity of silicone oil with various water contents and that of a single-row chain of glass beads in silicone oil were determined as a function of electric field and spacing between the particles produced by tensile and shear strain. The conductivity of the silicone oil depended sensitively on its water content; that of the chain was three orders of magnitude greater than the silicone oil alone, but decreased rapidly with separation of the particles. The conductivity of the water film on the glass bead surface and the electric field enhancement in the oil gap between the beads were derived from the data. The measured current density along a chain of particles was in accord with that predicted by a conductivity model for electrorheological response. At large strains the separation of the beads in a chain became localized between one set of adjacent beads and they oscillated back-and-forth in the gap, leading ultimately to rupture of the chain with increased strain.

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