Experiments and Models of the Magneto Rheological Behavior of High Weight Percent Suspensions of Carbonyl Iron Particles in Silicone Oil

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Farzad Ahmadkhanlou ◽  
Monon Mahboob ◽  
Stephen Bechtel ◽  
Gregory Washington
Keyword(s):  
Kinetic Theory ◽  
First Principles ◽  
Mechanical Response ◽  
Silicone Oil ◽  
Three Dimensional ◽  
Magnetic Behavior ◽  
Weight Percent ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Fluid Behavior

Flow properties of magnetorheological (MR) fluids are greatly altered by the application of a magnetic field. The design, optimization, and control of novel devices that exploit MR fluid behavior in multidegree of freedom applications require three dimensional models characterizing the coupling of magnetic behavior to mechanical behavior in MR fluids. The authors have derived 3D MR fluid models based on multiscale kinetic theory. The underlying bases of the models are summarized, with phenomenological empiricism distinguished from multiscale first principles, and the models’ ability to capture the experimentally measured mechanical response of a MR fluid-based damper to specified magnetic fields is assessed. The results of this comparison are that the kinetic theory-based models both relate macroscale MR fluid behavior to a first-principles description of magnetomechanical coupling at the microscale and possess the flexibility to best match the measured behavior of a particular MR fluid device observed in our experiments.

Nanometer and Micron Sized Particles in a Bidisperse Magnetorheological Fluid

2003 ◽  
Author(s):  
N. M. Wereley ◽  
J. Trihan ◽  
S. Kotha ◽  
A. Suggs ◽  
R. Radhakrishnan ◽  
...  
Keyword(s):  
Yield Stress ◽  
Silicone Oil ◽  
Maximum Yield ◽  
Weight Percent ◽  
High Yield ◽  
Settling Rate ◽  
Mr Fluid ◽  
Carrier Fluid ◽  
Solids Loading ◽  
Mr Fluids

Conventional magnetorheological (MR) fluids are suspensions of micron sized particles in a hydraulic or silicone oil carrier fluid. Recently, research has been conducted into the advantages of using bidisperse MR fluids, which are mixtures of two different powder sizes in the MR suspension. The MR fluids investigated here use a mixture of conventional micron sized particles and nanometer sized particles. The settling rate of such bidisperse fluids using nanometer sized particles is reduced because thermal convection and Van der Waals forces experienced by the nanometer sized particles compete favorably with gravitational forces. This reduction in the settling rate comes at a cost of a reduction in the maximum yield stress that can be manifested by such an MR fluid at its saturation magnetization. There is a measurable and predictable variation in rheological properties as the weight percent of the nanometer sized particles is increased relative to the weight percent of micron size particles, while maintaining a constant solids loading in the MR fluid samples. All bidisperse fluids tested in this study have a solids loading of 60 weight% (wt%) of Fe particles. This study investigates the effect of increasing the weight percent of 30 nanometer (nominal) Fe particles relative to 30 micron (nominal) Fe particles on rheological characteristics such as yield stress and postyield viscosity. The goal of this study is to find an optimal composition of the bidisperse fluid that provides the best combination of high yield stress and low settling rate based on empirical measurements. The applicability of rheological models, such as the Bingham-plastic and the Hershel Buckley models, to the measured flow curves of these MR fluids is also presented.

A Semi-Active, High-Torque, Magnetorheological Fluid Limited Slip Differential Clutch

2006 ◽  
Vol 128 (5) ◽  
pp. 604-610 ◽  
Author(s):  
Barkan Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Cahit Evrensel ◽  
Alan Fuchs ◽  
George Korol
Keyword(s):  
Response Time ◽  
Three Dimensional ◽  
Fast Response ◽  
Design Development ◽  
Element Analysis ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Mr Fluids ◽  
Torque Transmission ◽  
And Performance

The design, development, and performance characterization of a magnetorheological (MR) fluid clutch for automotive limited slip differential (LSD) applications is presented in this study. The controllability of MR fluids provides an adjustable torque transmission and slippage for the LSD application. Three-dimensional electromagnetic finite element analysis (FEA) is performed to optimize the magnetic circuit and clutch design. Based on the results obtained from the FEA, the theoretical torque transfer capacity of the clutch is predicted utilizing Bingham-Plastic constitutive model. The clutch is characterized at different velocities and electromagnet electric input currents. Both the torque transfer capacity and the response time of the clutch were examined. It was demonstrated that the proposed MR fluid LSD clutch is capable of transferring controllable high torques with a fast response time.

Performance of silicon oil-based Magneto-Rheological fluids used for MR dampers: an experimental approach

2021 ◽  
Vol 13 ◽  
Author(s):  
Mohamed Bakr ◽  
Tamer Nabil ◽  
Ali Eldomuaty ◽  
Tamer Mansour ◽  
Hossam Hammad ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Silicone Oil ◽  
Spherical Shape ◽  
Magnetic Behavior ◽  
Power Requirement ◽  
Mr Fluid ◽  
Lithium Grease ◽  
Working Temperature ◽  
Magneto Rheological

Aim: The aim of this work was preparation of the model Magneto Rheological (MR) fluids to be used under the effect of an applied magnetic field operated under very low power requirement for the purpose of vibration reduction in automotive damper. Background: Magneto-Rheological fluids are non-Newtonian fluids, which consist of magnetic particles scattered in a base liquid – a matter that can change their characteristics when applying the magnetic field. From the previous researches, Magneto-Rheological fluids have different properties according to the preparation accuracy, ingredients, particle size and shape, type of carrier fluids and stabilizer. Also, the response of Magneto-Rheological fluids to the magnetic flux varied. Methods: : A specimen of MR fluid is prepared using four different dynamic viscosities base fluids: Silicone oil JETTA (50mpa.s, 100mpa.s, 150mpa.s and 200mpa.s) are mixed with high purity spherical shape particles of Carbonyl Iron (CI). ABRO liquid white lithium grease is added to the specimen, and its effect is determined. Results: The presence of additives has no effect on the magnetic behavior; but rather increases dynamic viscosity, especially in the presence of the external magnetic field, which is considered as a stabilizing factor. Conclusion: Adding the white lithium grease as a stabilizer delays the sedimentation of the prepared sample by 1023%. The lowest sample in sedimentation rate has the highest viscosity, which satisfies 2.7% in 24 hours, but it shows a negative effect on the magneto-rheological properties, which leads to unstable viscosity readings due to MR fluid agglutination. Working temperature is a critical parameter that can affect the behavior of MR fluid; the viscosity of MR fluid under the effect of magnetic field is inversely proportional to the working temperature. Sample DELTA is the most promising for the application in automotive dampers which are used to decrease vehicle vibration. :

Synthesis and field dependent shear stress evaluation of stable MR fluid for brake application

2017 ◽  
Vol 69 (5) ◽  
pp. 655-665 ◽  
Author(s):  
Lijesh K.P. ◽  
Deepak Kumar ◽  
Harish Hirani
Keyword(s):  
Shear Stress ◽  
Oleic Acid ◽  
Silicone Oil ◽  
Ammonium Hydroxide ◽  
Iron Particles ◽  
Mr Fluid ◽  
Content Type ◽  
Weight Percentage ◽  
Mr Fluids ◽  
Brake Application

Purpose The purpose of this paper is to report on the development of magnetorheological (MR) fluids, having high on-state shear stress/viscosity, low off-state shear stress/viscosity, good redispersibility and stable suspension of carbonyl iron particles, using tetramethyl ammonium hydroxide (TAH) and oleic acid. Design/methodology/approach MR fluids for use in brakes are synthesized using different weight percentages of silicone oil, TAH, oleic acid and iron particles. The effects of TAH and oleic acid are studied. Shear stress is measured as a function of magnetic field on a magneto-rheometer. The images of MR particles settling with time are presented. The test set-up used to evaluate the performance of the MR fluids synthesized for brake application is detailed. Finally, a significant improvement in the MR performance of brakes is reported. Findings The MR fluid having 0.25 Wt.% oleic acid showed low off-state viscosity/shear stress and high on-state viscosity/shear stress. A higher weight percentage of TAH in the MR fluid further reduced the low off-shear stress and increased the high on-state shear stress with better stability. Originality/value Improvement of MR brake performance by adding surfactants like TAH and oleic acid has been the subject matter of several studies in the past, but these studies used a fixed percentage of surfactants in MR fluids. In the present work, the optimum percentage of TAH and oleic acid for an improved braking performance is determined by varying their content in the MR fluid, which has not been reported in any other work thus far.

scholarly journals A review on magnetically assisted abrasive finishing and their critical process parameters

2018 ◽  
Vol 5 ◽  
pp. 13 ◽  
Author(s):  
Chinu Kumari ◽  
Sanjay Kumar Chak
Keyword(s):  
Process Parameters ◽  
Silicone Oil ◽  
Mr Fluid ◽  
Carrier Medium ◽  
Mr Fluids ◽  
Abrasive Finishing ◽  
Critical Process Parameters ◽  
Removal Processes ◽  
Critical Process ◽  
Magnetically Assisted

Magnetically assisted abrasive finishing (MAAF) processes are the precision material removal processes that have been applied to a large variety of materials from brittle to ductile and from magnetic to non magnetic. The MAAF process relies on a unique “smart fluid”, known as Magnetorheological (MR) fluid. MR fluids are suspensions of micron sized magnetizable particles such as carbonyl iron, dispersed in a non-magnetic carrier medium like silicone oil, mineral oil or water. The MAAF processes overcome the limitation of abrasive flow machining by deterministically control the abrading forces by applying magnetic field around the workpiece. MAAF process is divided into two parts; one is magnetorheological finishing (MRF) and another is magnetorheological abrasive flow finishing (MRAFF). The MRAFF process gives better results as compared to results of MRF because it has additional reciprocating motion of MR fluid. In this article the attempt has been made to review various technical papers related to MRF and MRAFF. The experimental setups, process parameters, MR fluid, modeling & optimization and applications are discussed in this paper. This review article will be useful to academicians, researchers and practitioners as it comprises significant knowledge pertaining to MAAF.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

Magnetorheological Damping of Fragment Barrier Suspension Systems

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Kwon Joong Son ◽  
Eric P. Fahrenthold
Keyword(s):  
Ballistic Performance ◽  
Mr Fluid ◽  
Suspension Systems ◽  
Mr Fluids ◽  
Ballistic Protection ◽  
Protection Systems ◽  
Fluid Damping ◽  
Magnetorheological Damping ◽  
Impact Experiments ◽  
Very High

Magnetorheological (MR) fluids, well established as components of a variety of suspension systems, may offer opportunities to improve the performance of fabric ballistic protection systems, which typically do not incorporate significant energy dissipation mechanisms. A series of ballistic impact experiments has been conducted to investigate the potential of MR fluid damped fabric suspension systems to improve upon current fabric barrier designs. The results indicate that for the simple fabric suspension systems tested, MR fluid damping does not improve upon the very high weight specific ballistic performance of state of the art aramid fibers.

Hydrothermal synthesis, structure and magnetic properties of a three-dimensional cobalt(ii) – aminophenyltetrazolate coordination polymer

2014 ◽  
Vol 43 (19) ◽  
pp. 7263-7268 ◽  
Author(s):  
Tiffany M. Smith ◽  
Michael Tichenor ◽  
Yuan-Zhu Zhang ◽  
Kim R. Dunbar ◽  
Jon Zubieta
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Hydrothermal Synthesis ◽  
Coordination Polymer ◽  
Three Dimensional ◽  
Magnetic Behavior ◽  
Ac Magnetic Susceptibility

The three-dimensional [Co3(OH)2(H2O)2(aptet)4] exhibits magnetic properties consistent with a ferrimagnetic chain with the non-compensating resultant moment of one Co(ii) per trinuclear Co(ii) subunit and ac magnetic susceptibility indicative of glassy-like magnetic behavior.

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