scholarly journals Enhanced Magnetorheological Performance of Carbonyl Iron Suspension Added With Barium Ferrite Nanoparticle

2021 ◽  
Vol 8 ◽  
Author(s):  
Hyo Seon Jang ◽  
Qi Lu ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Barium Ferrite ◽  
Flow Behavior ◽  
Vibrating Sample Magnetometry ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Ferrite Nanoparticle ◽  
The Magnetic Field ◽  
Mr Characteristics

Hard-magnetic barium ferrite (BF) nanoparticles with a hexagonal plate-like structure were used as an additive to a carbonyl iron (CI) microparticle-based magnetorheological (MR) fluid. The morphology of the pristine CI and CI/BF mixture particles was examined by scanning electron microscopy. The saturation magnetization and coercivity values of each particle were measured in the powder state by vibrating sample magnetometry. The MR characteristics of the CI/BF MR fluid measured using a rotation rheometer under a range of magnetic field strengths were compared with those of the CI-based MR fluid. The flow behavior of both MR fluids was fitted using a Herschel–Bulkley model, and their stress relaxation phenomenon was examined using the Schwarzl equation. The MR fluid with the BF additive showed higher dynamic and elastic yield stresses than the MR fluid without the BF additive as the magnetic field strength increased. Furthermore, the BF nanoparticles embedded in the space between the CI microparticles improved the dispersion stability and the MR performance of the MR fluid.

Development and Verification of Viscoelasticity Measurement System of MR Fluids in Magnetic Field

2012 ◽  
Vol 721 ◽  
pp. 114-119 ◽  
Author(s):  
Yuta Enokizono ◽  
Takashi Todaka ◽  
Masato Enokizono
Keyword(s):  
Magnetic Field ◽  
Measurement System ◽  
High Speed ◽  
Uniform Magnetic Field ◽  
Precise Measurement ◽  
Mr Fluid ◽  
Knowledge Based ◽  
Mr Fluids ◽  
The Magnetic Field ◽  
Speed Response

MR (Magnetic Rheological) fluid is a kind of functional fluid, which can be hardened by impressing magnetic flux. MR fluid has the high speed response to the external magnetic field and a big yield stress in comparison with the ferrofluid. In recent years, various devices utilizing MR fluid have been developed. Such developments are enabled with knowledge based on measured viscoelastic properties of MR fluid. However, precise measurement to obtain effect of the magnetic field on viscoelasticity is very difficult. The difficulty exists in generating a uniform magnetic field and evaluating the effective magnetic field. Accurate measurements become possible by solving these problems. In this paper, we propose a new magneto-viscoelasticity measurement system of MR fluid, which can generate a uniform magnetic field.

Magnetic Circuit Simulation for Magnetorheological (MR) Fluids Testing Rig in Squeeze Mode

2010 ◽  
Vol 123-125 ◽  
pp. 991-994 ◽  
Author(s):  
Izwan Ismail ◽  
Saiful Amri Mazlan ◽  
Abdul Ghani Olabi
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Field Distribution ◽  
Circuit Simulation ◽  
Magnetic Field Distribution ◽  
Mr Fluid ◽  
Flux Lines ◽  
Mr Fluids ◽  
Magnetic Flux Lines ◽  
The Magnetic Field

In this study, a testing rig in squeeze was designed and developed with the ability to conduct various tests especially for quasi-static squeezing at different values of magnetic field strength. Finite Element Method Magnetics (FEMM) was utilized to simulate the magnetic field distribution and magnetic flux lines generation from electromagnetic coil to the testing rig. Tests were conducted with two types of MR fluid. MRF-132DG was used to obtain the behaviour of MR fluid, while synthesized epoxy-based MR fluid was used for investigating the magnetic field distribution with regards to particle chains arrangement. Simulation results of the rig design showed that the magnetic flux density was well distributed across the tested materials. Magnetic flux lines were aligned with force direction to perform squeeze tests. Preliminary experimental results showed that stress-strain pattern of MR fluids were in agreement with previous results. The epoxy-based MR samples produced excellent metallographic samples for carbonyl iron particles distributions and particle chain structures investigation.

Shear and Squeeze Rheometry of Magnetorheological Fluids

2011 ◽  
Vol 305 ◽  
pp. 344-347 ◽  
Author(s):  
Hong Yun Wang ◽  
Hui Qiang Zheng
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Electrical Current ◽  
Test System ◽  
Compression Stress ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Shear Yield ◽  
The Magnetic Field

The mechanical properties of a magnetorheological (MR) fluid in shearing, compression and shearing after compression have been studied in the magnetic field which is generated by a coil carrying different magnitudes of DC electrical current on a self-constructed test system. The relations of compression stress versus compression strain, yield stress versus compression stress were studied under different magnetic fields. The compressing tests showed that the MR fluid is very stiff at small compressive strains lower than 0.13. The shear yield stress of MR fluids after compression was much stronger than that of uncompressed MR fluids under the same magnetic field. The enhanced shear yield stress of MR fluids can be utilized to design the MR clutch and brake for new structure and will make MR fluids technology attractive for many applications.

Combined Squeeze-Shear Properties of Magnetorheological Fluids: Effect of Pressure

2012 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Magnetic Field ◽  
Positive Interaction ◽  
Technical Literature ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Pressure Dependency ◽  
Experimental Apparatus ◽  
Strengthen Effect ◽  
System Requirements ◽  
The Magnetic Field

Several applications of magnetorheological (MR) fluids are nowadays present in the industrial world, however sometimes system requirements require better material properties. In technical literature an interesting previous work shows that MR fluids exhibit a pressure dependency called squeeze strengthen effect. Since a lot of MR fluid based devices are rotary devices, this paper investigates the behaviour of MR fluids under pressure when a rotation is applied to shear the fluid. The system is designed in order to apply both the magnetic field and the pressure following a Design of Experiment method. The experimental apparatus comprises a cylinder in which a piston is used both to apply the pressure and to apply a prescribed rotation. The magnetic circuit is designed to provide a nearly constant induction field in the MR fluid. The experimental apparatus measures torque as a function of the variables considered and the yield shear stress is computed. A statistical analysis of the results shows that there is a positive interaction between magnetic field and pressure, which enhance the MR fluid performances more than two times.

scholarly journals Squeezing Force of the Magnetorheological Fluid Isolating Damper for Centrifugal Fan in Nuclear Power Plant

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jin Huang ◽  
Ping Wang ◽  
Guochao Wang
Keyword(s):  
Nuclear Power ◽  
Theoretical Foundation ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Magnetorheological Fluid ◽  
Centrifugal Fan ◽  
Parallel Channel ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Control Devices

Magnetorheological (MR) disk-type isolating dampers are the semi-active control devices that use MR fluids to produce controllable squeezing force. In this paper, the analytical endeavor into the fluid dynamic modeling of an MR isolating damper is reported. The velocity and pressure distribution of an MR fluid operating in an axisymmetric squeeze model are analytically solved using a biviscosity constitutive model. Analytical solutions for the flow behavior of MR fluid flowing through the parallel channel are obtained. The equation for the squeezing force is derived to provide the theoretical foundation for the design of the isolating damper. The result shows that with the increase of the applied magnetic field strength, the squeezing force is increased.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

Internal Organizational Measurement for Control of Magnetorheological Fluid Properties

2006 ◽  
Vol 129 (4) ◽  
pp. 423-428 ◽  
Author(s):  
John R. Lloyd ◽  
Miquel O. Hayesmichel ◽  
Clark J. Radcliffe
Keyword(s):  
Magnetic Field ◽  
Physical Properties ◽  
High Sensitivity ◽  
Time Varying ◽  
Measurable Effect ◽  
Mr Fluid ◽  
Fluid State ◽  
Mr Fluids ◽  
Fluid Properties ◽  
Field Excitation

Magnetorheological (MR) fluids change their physical properties when subjected to a magnetic field. As this change occurs, the specific values of the physical properties are a function of the fluid’s time-varying organization state. This results in a nonlinear, hysteretic, time-varying fluid property response to direct magnetic field excitation. Permeability, resistivity and permittivity changes of MR fluid were investigated and their suitability to indicate the organizational state of the fluid, and thus other transport properties, was determined. High sensitivity of permittivity and resistivity to particle organization and applied field was studied experimentally. The measurable effect of these material properties can be used to implement an MR fluid state sensor.

Encapsulation of Carbonyl Iron Particles with Poly(Vinyl Butyral) and their Magnetorheology

2007 ◽  
Vol 334-335 ◽  
pp. 193-196
Author(s):  
Jae Lim You ◽  
B.J. Park ◽  
I.B. Jang ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Mineral Oil ◽  
Iron Particles ◽  
Carrier Liquid ◽  
Mr Fluids ◽  
Fluid Systems ◽  
Ft Ir ◽  
Vinyl Butyral

To enhance dispersion stability of magnetorheological (MR) fluids, hybrid magnetic particles of carbonyl iron (CI)/ poly(vinyl butyral) (PVB) with core/shell microstrcutre (CI-PVB) were prepared, since pure magnetic CI based MR fluid systems show severe sedimentation of the CI particles due to the large density mismatch with the carrier liquid and difficulties in redispersion after caking. The composite particles of CI-PVB have a lower density than that of the pure CI particles, while exhibiting almost original magnetic property of the CI. Both CI and CI-PVB particles were dispersed in mineral oil (20 vol%) and their MR characteristics were examined via a rotational rheometer with a magnetic field supplier. Various characterizations of the CI-PVB particles were performed via SEM, TEM and FT-IR. Both yield stress and flow curve of shear stress as a function of shear rate of the MR fluids were investigated under applied magnetic field strengths.

Platform Design for Characterizing Shear Force Produced by Magnetized Magnetorheological Fluid

2019 ◽  
Author(s):  
Ping-Hsun Lee ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Yield Stress ◽  
Flux Density ◽  
Shear Force ◽  
Permanent Magnets ◽  
Magnetic Flux Density ◽  
Finite Element Method Result ◽  
Mr Fluid ◽  
The Magnetic Field

Abstract In this paper we proposed a platform for measuring shear force of magnetorheological (MR) fluid by which the relationship of yield stress and magnetic flux density of specific material can be determined. The device consisted of a rotatable center tube in a frame body and the magnetic field was provided by two blocks of permanent magnets placed oppositely outside the frame body. The magnitude and direction of the magnetic field were manipulated by changing the distance of the two permanent magnets from the frame body and rotating the center tube, respectively. For determining the magnetic field of the device, we adopted an effective method by fitting the FEM (finite element method) result to the measured one and then rebuilt the absent components to approximate the magnetic field, which was hardly to be measured simultaneously as different device setup were required. With the proposed platform and analytical methods, the drawing shear force and the corresponding yield stress contributed by MR fluid could be evaluated in respect to the magnitude and direction of given magnetic flux density with acceptable accuracy for specific designing purposes without a large, complex, and expensive instrument.

PREPARATION AND ABRASION PROPERTIES OF MAGNETO-RHEOLOGICAL FLUID OF DISPERSED SILICA-COATED IRON

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1121-1127 ◽  
Author(s):  
A. SHIBAYAMA ◽  
T. OTOMO ◽  
Y. AKAGAMI ◽  
K. SHIMADA ◽  
T. FUJITA
Keyword(s):  
Carbonyl Iron ◽  
Spherical Particles ◽  
Fluid Viscosity ◽  
Iron Particles ◽  
Mr Fluid ◽  
Abrasion Test ◽  
Silicon Oil ◽  
Mr Fluids ◽  
Transmission Oil ◽  
Magneto Rheological

In this study, a magneto-rheological fluid dispersed by silica-coated iron was developed and its properties such as fluid viscosity (shear stress or shear rate) and abrasion were investigated. The metallic iron coated by silica dispersed in magneto-rheological fluid was prepared by H 2 reducing of precipitated magnetite ( Fe 3 O 4). Then, the magneto-rheological fluid (MR fluid) for the seal was prepared with silica-coated iron or carbonyl iron (HQ type; diameter of 1.6-1.9 10-6m) and two solvent oils i.e. silicon oil (SH200cv, 10000cSt) and CVT oil (T-CVTF, automobile transmission oil). It was observed that the MR fluid viscosity of CVT oil with HQ particles is lower in every fluid condition. Furthermore, the surface roughness of polyvinyl plate after abrasion test for MR fluid with silica coated iron and CVT oil as solvent was higher compared to the other types of MR fluids. The results indicated that carbonyl iron (spherical particles) and silica-coated iron particles dispersed in silicon oil are feasible to be used where the low abrasion in mechanics is required.

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