Investigation of Thermal Conductivity of Alumina/Silicone Oil Electrorheological Fluids

2010 ◽  
Vol 129-131 ◽  
pp. 421-425 ◽  
Author(s):  
Yi Chun Wang ◽  
Xiao Xia Sun ◽  
Xiao Rong Tang ◽  
Fa Cheng Wang
Keyword(s):  
Thermal Conductivity ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Silicone Oil ◽  
Conductivity Measurement ◽  
Electrorheological Fluids ◽  
High Voltage Power Supply ◽  
Heating Device ◽  
Er Fluids

Electrorheological (ER) fluids are new materials with good properties such as dielectric constant, dielectric loss or conductivity, which display remarkable rheological behavior, being able to convert rapidly and repeatedly from a liquid to solid when an electric field is applied or removed. In this study, suspensions of alumina (A) were prepared in silicone oil (SO). The effects of electric field strength and temperature of the suspensions on thermal conductivity were determined. Thermal conductivity measurement in different conditions was carried out via experimental instrument with high-voltage power supply and water heating device to investigate the effects of electric field strength and temperature on ER performance and thermal conductivity. The results show that the thermal conductivity is in accordance with ER properties enhanced by increasing the field strength and decreasing the temperature.

Investigation of vibration damping properties of electroactive polyanthracene/silicone oil dispersions

2021 ◽  
pp. 1045389X2110235
Author(s):  
Gokce Calis Ismetoglu ◽  
Halil Ibrahim Unal
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Silicone Oil ◽  
Vibration Damping ◽  
Elastic Behavior ◽  
Creep Recovery ◽  
Damping Properties ◽  
Sem Image ◽  
Er Fluids

Electrorheological (ER) fluids generate mechanical responses to applied electric field strength via changing their rheological properties from liquid to solid and vice-versa reversibly. As a result of this, ER fluids can be used in the industrial vibration damping systems. In order to increase applicability of ER fluids, it is necessary to understand electric field induced polarization and ER mechanism of different materials. Therefore, the aim of this study is to illuminate ER and vibration damping properties of polyanthracene (PAT), which is a new material for ER studies. PAT was synthesized from anthracene and characterized by several techniques namely: ATR-FTIR spectroscopy, particle size, SEM image, four-point probe conductivity, and magnetic susceptibility measurements. A series of PAT/silicone oil (SO) dispersions having various concentrations were prepared and subjected to dielectric and ER tests. Then, the colloidal stabilities of 20% PAT/SO and 20% PAT/SO/TritonX systems were determined. Dynamic viscoelastic data obtained by the oscillation tests showed that viscous behavior was dominant under zero electric field, whereas elastic behavior was prevailing under external electric field strength and highlighting the vibration damping characteristics of PAT/SO dispersion. In the creep-recovery measurements, the highest %recovery was recorded to be 62% indicating potential industrial use of PAT/SO dispersion.

Water-Activated Bacterial Cellulose-Based Electrorheological Fluids and Electromechanical Response of Artificial Muscle Based on Electrorheological Fluids and Siloxane Gel

2009 ◽  
Vol 87-88 ◽  
pp. 143-148
Author(s):  
Nai Xu ◽  
De Min Jia
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Bacterial Cellulose ◽  
Yield Stress ◽  
Particle Concentration ◽  
Electrorheological Fluids ◽  
Water Yield ◽  
Composite Gel

Electrorheological (ER) characteristics of ER fluids (ERF) containing bacterial cellulose (BC) particles in silicone oil was investigated as a function of particle water content, DC electric field strength and particle concentration. It was found that the existence of water in BC particles strongly influenced the performance of water-activated ERF based on BC particles. Around 8.8 wt% water, yield stress reached its maximum valve of 1118 Pa after which it decreased with increasing water content. At the same water content, yield stress increased linearly with increasing in either electric field strength or particle concentration. The ERF based on BC particles was introduced into the poly (dimethylsiloxane) (PDMS) gels to prepare electric field sensitive composite gel. Electric fields were applied to these composite gels using flexible electrodes. Compressions of these gels with varying PDMS/ERF ratios were confirmed by the electrode displacement. It was found that 50/50 PDMS/ERF gel exhibited the maximum displacement of 102um at 2 kV/mm electric field.

DYNAMIC PERFORMANCE OF CANTILEVER COMPOSITE MORTAR BEAMS WITH ELECTRO-RHEOLOGICAL FLUID

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1703-1709 ◽  
Author(s):  
JINGZHOU LU ◽  
QINGBIN LI
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Physical Mechanism ◽  
Dynamic Performance ◽  
Structural Vibration ◽  
Structural Vibration Control ◽  
Smart Beam ◽  
Er Fluids ◽  
The Impact

The work presented in this paper bears on the feasibility and the operative technology of embedding electro-rheological (ER) fluids into cement mortar. We have made a cantilever mortar beam with controllable ER fluids filled in a central crack for the purpose of investigation on the evolutional rule of frequencies under different electric field strength by hammering test. The experimental results indicated that the influence of electric field strength upon the first frequency is more evident than that upon the second one, whereas that upon the third frequency is very little. In addition, the physical mechanism of the impact of the change of voltage on the frequency of smart beam structures embedded with ER fluids was discussed. This research sets up an experimental basis for the application of ER fluids in the domain of structural vibration control.

ELECTROSTATIC INTERACTIONS FOR PARTICLE ARRAYS IN ELECTRORHEOLOGICAL FLUIDS II: MEASUREMENTS

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2895-2902 ◽  
Author(s):  
YING CHEN ◽  
H. CONRAD
Keyword(s):  
Shear Modulus ◽  
Electric Field ◽  
Shear Strain ◽  
Enhancement Factor ◽  
Shear Force ◽  
Electrostatic Interactions ◽  
Silicone Oil ◽  
Electrorheological Fluids ◽  
Proportionality Constant ◽  
Er Fluids

The force required to shear one-, two- and three-chain clusters of 230 µm dia. glass beads in silicone oil was measured. In each case the shear force was proportional to the shear strain, the proportionality constant increasing with electric field and number n of chains in the cluster. The derived shear modulus G also increased with n. An extrapolation of the present results suggests that a cluster of 4–5 chains would give the stress enhancement factor of 10–20 observed for real 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.

Ultralow lattice thermal conductivity and dramatically enhanced thermoelectric properties of monolayer InSe induced by external electric field

2021 ◽  
Author(s):  
Zheng Chang ◽  
Kunpeng Yuan ◽  
Zhehao Sun ◽  
Xiaoliang Zhang ◽  
Yufei Gao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
External Electric Field ◽  
Thermoelectric Properties ◽  
Electrostatic Interaction ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance

With the ability of altering the inherent interatomic electrostatic interaction, modulating external electric field strength is a promising approach to tune the phonon transport behavior and enhance thermoelectric performance of...

Electrorheological Fluid Hysteresis

Materials ◽  
2005 ◽  
Author(s):  
Young Dae Kim ◽  
Daniel De Kee
Keyword(s):  
Shear Rate ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Particle Concentration ◽  
Electrorheological Fluid ◽  
Particle Structure ◽  
Hysteresis Behavior ◽  
Precise Control ◽  
Er Fluids

Electrorheological (ER) fluids are suspensions of polarizable particles dispersed in insulating liquids. They exhibit a rapid and reversible transition from a liquid-like to a solid-like state upon the application of an electric field. The observed shear stress - shear rate hysteresis makes the precise control of the ER mechanical devices very difficult. Hysteresis behavior of TiO2 ER fluids were observed by varying particle concentration, electric field strength, maximum shear rate, and the time of hysteresis loop. In the absence of an electric field, the stress level of the up curve exceeds that of the down curve. The presence of an electric field, reverses this trend. The extent of hysteresis becomes more significant with increasing electric field strength, particle concentration, and maximum shear rate. Hysteresis behavior of TiO2 ER fluids seems to arise mainly due to the change of the particle structure during shearing. To describe the complex rheological behavior of ER fluids, a kinetic theory is presented. Model predictions show qualitative agreement with the experimental hysteresis data.

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