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.

HYDRODYNAMIC CHARACTERISTICS OF ELECTRORHEOLOGICAL FLUID IN A PARALLEL DUCT FLOW

2001 ◽  
Vol 15 (06n07) ◽  
pp. 980-987
Author(s):  
K. SHIMADA ◽  
S. KAMIYAMA
Keyword(s):  
Shear Rate ◽  
Friction Coefficient ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Apparent Viscosity ◽  
Wall Friction ◽  
Hydrodynamic Characteristics ◽  
Duct Flow ◽  
Newtonian Viscosity

An experimental investigation is conducted to clarify the hydrodynamic characteristics of ERF with elastic particles of smectite in a two-dimensional parallel duct of various widths. Experimental data on pressure difference to a volumetric flow rate in a supplying D.C. electric field are measured. These data are arranged to obtain the apparent viscosit by using the integral method of rheology. From the data of apparent viscosity, the wall friction coefficient is obtained. The increment of the apparent viscosity caused by the applying electric field is a function of shear rate as well as the electric field strength and the width of the duct. However, the wall friction coefficient is not a function of elecric field strength and the width of the parallel duct, but only of shear rate. The yield stress is a function of the width of the parallel duct as well as of electric field strength. The ratio of Non-Newtonian viscosity in the apparent viscosity is varied by the intensity of the shear rate.

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.

DIFFERENCES IN STEADY CHARACTERISTICS AND RESPONSE TIME OF ERF ON ROTATIONAL FLOW BETWEEN ROTATING DISK AND CONCENTRIC CYLINDER

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1050-1056 ◽  
Author(s):  
K. SHIMADA ◽  
H. NISHIDA ◽  
T. FUJITA
Keyword(s):  
Shear Rate ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Current Density ◽  
Rotating Disk ◽  
Settling Time ◽  
Rotational Flow ◽  
Concentric Cylinder ◽  
Constant Shear Rate

We made an experimental investigation of the steady characteristics of torque, current density, and response time of ERF on rotational flow of the disk and the concentric cylinder. We used smectite particles suspension ERF and D.C. electric field. We compared the steady shearstress, current density, and the rise and settling time of the concentric cylinder and with those of the rotating disk. Then we clarified the differences. At a larger electric field strength, the shear stress, yield stress, and apparent viscosity to a constant shear rate in the case of the rotating disk are larger than they are in the case of the rotating concentric cylinder. However, at a larger electric field strength, the current density to a constant shear rate in the case of the rotating disk is smaller than it is in the case of the rotating concentric cylinder. Rise time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder. However, rise time of current density in the case of the rotating disk is slower than it is in the case of the rotating concentric cylinder at a small electric field strength. On the other hand, the difference of settling time of torque and current density between the rotating disk and the rotating concentric cylinder is changed by the electric field strength and shear rate. The settling time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder at a large electric field strength and large shear rate. The settling time of current density in the case of the rotating disk is slower than it is in the case of rotating concentric cylinder at a small electric field strength. Based on these results, the rotating disk has an efficiency of obtained torque to given electric power greater than that of the rotating concentric cylinder.

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.

Properties and Structure of Ni/TiO2/Polar Molecule Core-Shell Particles Electrorheological Fluid

2012 ◽  
Vol 512-515 ◽  
pp. 2166-2170
Author(s):  
Suo Kui Tan ◽  
Xiao Ping Song ◽  
Hong Zhao ◽  
Song Ji ◽  
Li Qiao ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electrorheological Fluid ◽  
Polar Molecule ◽  
Fluid Properties ◽  
Structure Observation ◽  
Shell Particles ◽  
The Relationship ◽  
Er Fluid

By means of mechanical properties test and structure observation， the relationship among electric field strength, polar molecule type, content on the Ni/TiO2group electrorheological fluid properties have been analyzed. It is found that with increasing electric field strength，the properties of electrorheological fluid increased for same composition ER fluid. Different type polar molecules have distinct effect. For same particle，with increasing polar molecule content，the property is increased, but there is a critical value . Polar molecule make particles chain of electrorheological fluid become strong，coarse and interweaved each other.

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.

Electrorheological Response of Polyaniline Particles Embedded in Cross-Linked Poly(Dimethyl Siloxane) Networks

Materials ◽  
2005 ◽  
Author(s):  
Piyanooth Hiamtup ◽  
Anuvat Sirivat
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Crosslink Density ◽  
Particle Concentration ◽  
Shear Mode ◽  
Zero Field ◽  
Dimethyl Siloxane ◽  
The Matrix ◽  
Electromechanical Responses

Electrorheological characteristics of poly (dimethyl siloxane) (PDMS) networks containing camphorsulfonic acid (CSA) doped-polyaniline (PANI) particles were investigated. Samples were prepared by dispersing fine polyaniline particles into cross-linked PDMS. Rheological properties of the PANI/PDMS blends were studied in the oscillatory shear mode in order to study the effects of electric field strength, crosslink density of the matrix, particle concentration, and operating temperature on their electromechanical responses. The electrostriction of the blends were observed as a result of an attractive force among polarized particles embedded in the network. The sensitivity values of blends are defined as the storage moduli at any applied electric field subtracted by those values at zero electric field, and divided by the moduli at zero field. They were found to increase about 10-50% when electric field strength was increased to 2 kV/mm. These moduli values increased with particle concentration and temperature but they decreased with crosslink density of the matrices.

STUDY ON PROPERTIES OF ELECTRORHEOLOGICAL FLUID AND ITS APPLICATION IN MACHINING VIBRATION CONTROL

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1710-1716 ◽  
Author(s):  
YONGLIANG ZHANG ◽  
JUNYI YU ◽  
DONGXIA HOU ◽  
SHOUQIN ZHANG ◽  
HUA WU
Keyword(s):  
Mechanical Properties ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Engineering Application ◽  
Electrorheological Fluid ◽  
Suppressive Effect ◽  
Dynamic Mechanical Properties ◽  
Shear Mode ◽  
Lathe Tool

The better mechanical properties of Electrorheological fluid (ERF) are critical for its engineering application. In this paper, the effects of electric field strength and circumstance temperature on steady flow characteristic of ERF are analyzed; the effects of electric field strength, vibration amplitude, vibration frequency and circumstance temperature on ERF's dynamic mechanical properties are investigated using orthogonal tests. In addition, the ERF damper of lathe tool slide worked on shear-mode is developed; the turning experiments with the damper are performed in order to validate the suppressive effect of vibration. The experimental results demonstrate that ERF dampers can decrease the machining vibration response effectively.

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.

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.

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