scholarly journals Synthesis and Characterization of Magnetorheological Fluids

2020 ◽  
Vol 9 (6) ◽  
pp. 272-277
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Temperature Stability ◽  
High Strength ◽  
Industrial Applications ◽  
Magnetorheological Fluids ◽  
Carrier Fluid ◽  
Performance Requirements ◽  
Mr Fluids ◽  
Mr Effect

Magnetorheological fluids (MRF) are mixture of ferromagnetic micron sized particles in silicon or hydraulic oil carrier fluid. By application of external varying strength magnetic field various physical properties of these fluids can be controlled and they becomes semi-solids depending on magnetic field strength application.MR fluids fulfill the desired performance requirements i.e. on application of magnetic field exhibits high shear and low initial viscosity, quick response , low hysteresis, low power consumption and temperature stability These special properties of MR fluids made them suitable for many type of industrial applications including machining. Hence fluids can be very effectively used in magnetorheological finishing process (MRF) which has unique feature of finishing truncated and complicated geometrical shapes and surfaces and capable of producing surface in nanometers. As surface finish is an important parameter in precision fits, product quality, and high-strength applications. The three dimensional surfaces finishing works such as different angled deep pockets or projections. Many industries have this type of i.e. mould & dies manufacturing, automobiles manufacturing, aerospace industry, semiconductor machining and optics machining etc. Such application leads to enhanced demand of nano-finishing of 3D surfaces without damaging surfaces/sub-surfaces. As due to change in properties because of change in composition the MR effect is also influenced. Therefore the composition of MR fluids is very important to achieve desired MR effect. The composition of magnetorheological fluids can be evaluated with the help of characterizations and desire MR fluid can be synthesized according to requirements of the process. This paper will explain in detail how we can synthesize and characterize the Magnetorheological fluids using state of the art equipments and can optimize their performance.

scholarly journals A review of challenges and solutions in the preparation and use of magnetorheological fluids

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
James Sathya Kumar ◽  
P. Sam Paul ◽  
Girish Raghunathan ◽  
Divin George Alex
Keyword(s):  
Magnetic Field ◽  
Magnetorheological Fluid ◽  
Magnetorheological Fluids ◽  
Future Application ◽  
Engineering Systems ◽  
Carrier Fluid ◽  
Aircraft Landing ◽  
Mr Fluids ◽  
Strength Based ◽  
External Stimuli

AbstractThis review of MRF (magnetorheological fluids or MR fluids) brings out the challenges in methods of preparation, difficulties encountered in storage and use, and possible solutions to overcome the challenges.Magnetorheological fluid in the rheological fluid domain has found use due to its ability to change its shear strength based on the applied magnetic field. Magnetorheological fluids are composed of magnetizable micron-sized iron particles and a non-magnetizable base or carrier fluid along with additives to counter sedimentation and agglomeration.Magnetorheological fluids can respond to external stimuli by undergoing changes in physical properties thus enabling several improved modifications in the existing technology enhancing their application versatility and utility. Thus, magnetorheological fluid, a rheological material whose viscosity undergoes apparent changes on application of magnetic field, is considered as a smart material. Such materials can be used for active and semi-active control of engineering systems.Many studies on the designs of systems incorporating MR fluids, mainly for vibration control and also for other applications including brakes, clutches, dynamometers, aircraft landing gears, and helicopter lag dampers, have emerged over last couple of decades. However, the preparation as well as the maintenance of magnetorheological fluids involves several challenges. Sedimentation is a major challenge, even when stored for moderate periods of time. A comprehensive review is made on the problems confronted in the preparation of magnetorheological fluids as well as sustenance of the properties, for use, over a long period of time. Other problems encountered include agglomeration and in-use thickening (IUT) as well as rusting and crusting. Of interest is the mitigation of these problems so as to prepare fluids with satisfactory properties, and such solutions are reviewed here. The control of magnetorheological fluids and the applications of interest are also reviewed.The review covers additives for overcoming challenges in the preparation and use of magnetorheological fluids that include incrustation, sedimentation, agglomeration, and also oxidation of the particles. The methodology to prepare the fluid along with the process for adding selected additives was reviewed. The results showed an improvement in the reduction of sedimentation and other problems decreasing comparatively. A set of additives for addressing the specific challenges has been summarized. Experiments were carried out to establish the sedimentation rates for compositions with varying fractions of additives.The review also analyzes briefly the gaps in studies on MR fluids and covers present developments and future application areas such as haptic devices.

scholarly journals On the apparent yield stress in non-Brownian magnetorheological fluids

Soft Matter ◽  
2017 ◽  
Vol 13 (39) ◽  
pp. 7207-7221 ◽  
Author(s):  
Daniel Vågberg ◽  
Brian P. Tighe
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Computer Simulations ◽  
Magnetorheological Fluids ◽  
Universal Behavior ◽  
Carrier Fluid ◽  
Mr Fluids

The viscosity of magnetorheological (MR) fluids can be increased dramatically by applying a magnetic field. Some MR fluids display a clear yield stress, while others do not. Using computer simulations, we rationalize this non-universal behavior in terms of the viscous interactions between particles and the carrier fluid.

Visualizing Rheological Mechanism of Magnetorheological Fluids

2021 ◽  
Author(s):  
Yurui Shen ◽  
Dezheng Hua ◽  
Xinhua Liu ◽  
Weihua Li ◽  
Grzegorz Krolczyk ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Magnetic Dipole ◽  
Laser Scanning ◽  
Magnetic Particles ◽  
Three Dimensional ◽  
Confocal Laser Scanning Microscope ◽  
Magnetorheological Fluids ◽  
Confocal Laser ◽  
Observation Method

Abstract In order to study the rheological properties of aqueous magnetorheological fluids (MRFs) from microscopic point of view, an experimental observation method based on the fluorescence confocal laser scanning microscope is proposed to clearly produce the chain shape of the magnetic particles. Firstly, the mathematical model of the magnetic particles is established in a magnetic field using the magnetic dipole theory, and the MRFs with different fraction volumes and different magnetic fields are investigated. Furthermore, an aqueous MRFs experiment is prepared, in which the magnetic particles are combined with Alexa 488 fluorescent probe. On this basis, an observation method is innovatively developed using two-dimensional (2D) and three-dimensional (3D) image analysis by the fluorescence confocal microscope. The rheological mechanism of the aqueous MRFs is investigated using four different types of MRFs in an external magnetic field. The analysis results demonstrate that the simulation and experimental rheological properties of the MRFs are consistent with the magnetic dipole theory. Moreover, the proposed method is able to real-time observe the rheological process of the MRFs with a very high resolution, which ensures the correctness of the analysis results of the rheological mechanism.

Patterned Magnetorheological Elastomer Developed by 3D Printing

2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Magnetic Particles ◽  
Layer By Layer ◽  
Carrier Fluid ◽  
Vibration Technique ◽  
Mode Of Operation ◽  
3D Printed ◽  
Mr Effect

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.

Experimental Investigation into the Effect of a Magnetic Field on Magnetorheological Fluids under an Impact Load

2012 ◽  
Vol 721 ◽  
pp. 179-184
Author(s):  
Ahmad Isnikurniawan ◽  
Yoshitaka Moroka ◽  
Hiromichi Ohba ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Qualitative Analysis ◽  
Apparent Viscosity ◽  
Impact Load ◽  
Magnetorheological Fluids ◽  
Mr Fluids ◽  
Experimental Apparatus ◽  
The Impact ◽  
The Magnetic Field

The apparent viscosity of magnetorheological (MR) fluids changes in the presence of a magnetic field. The stronger the magnetic field applied, the more the apparent viscosity increases. An increase in the apparent viscosity increases the restriction on the flow of MR fluids. In this study, we perform a qualitative analysis to investigate the effect of a magnetic field on MR fluids under an impact load. An experimental apparatus that consists of a drop-test tower was developed to simulate the impact load, and an MR fluid in a U-pipe was subjected to the impact load via a piston rod. In the experiment, we measured the displacement and velocity of the piston rod. On the basis of the results, the influence of a given magnetic field on the behavior of MR fluids under an impact load is discussed.

MAGNETORHEOLOGICAL FLUIDS AND THEIR PROPERTIES

2005 ◽  
Vol 19 (01n03) ◽  
pp. 593-596 ◽  
Author(s):  
J. M. HE ◽  
J. HUANG
Keyword(s):  
Magnetic Field ◽  
Yield Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Applied Magnetic Field ◽  
Magnetorheological Fluids ◽  
Mr Fluid ◽  
Variable Yield ◽  
Mr Fluids

Magnetorheological (MR) fluids are materials that respond to an applied magnetic field with a change in their rheological properties. Upon application of a magnetic field, MR fluids have a variable yield strength. Altering the strength of the applied magnetic field will control the yield stress of these fluids. In this paper, the method for measuring the yield stress of MR fluids is proposed. The curves between the yield stress of the MR fluid and the applied magnetic field are obtained from the experiment. The result indicates that with the increase of the applied magnetic field the yield stress of the MR fluids goes up rapidly.

Experimental Investigation of the Transient Behavior of MR Fluids

2011 ◽  
Author(s):  
Ju¨rgen Maas ◽  
Dirk Gu¨th
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Response Time ◽  
Dynamic Properties ◽  
Transient Behavior ◽  
Current Control ◽  
Large Signal ◽  
Carrier Fluid ◽  
Mr Fluids ◽  
The Magnetic Field

The transient behavior of MRF actuators is an important property for certain applications that is mainly affected by three delays, occurring from the dynamic properties of the coil current, the magnetic field and the torque generation by the MRF. In order to investigate the transient behavior of the generated torque with respect to the magnetic field, which is mainly affected by the motion of the MR particles in the carrier fluid, the mentioned response time of the electrical and magnetic domains must be in an appropriated ratio in comparison to the MRF response time to obtain reliable results by experiments. Therefore a special disc-type test actuator with outstanding dynamics is designed that minimizes the delays by the use of an ultrafast current control and a magnetic core made of soft ferrite material for preventing the effects of eddy currents. For the experimental investigation of the transient behavior of MR fluids, the small signal as well as the large signal behavior is analyzed for different test signals and load conditions of the actuator. Various results of the investigated transient behavior are shown finally for two different MR fluids featuring response times of about 1 ms for the fluid itself and switching times of about 4 ms for the MRF actuator.

Design and Performance Analysis on MR-Shock Absorber

2014 ◽  
Vol 984-985 ◽  
pp. 648-655
Author(s):  
M.L. Brabin Nivas ◽  
T. Prabaharan ◽  
J. Libin ◽  
T. Bibin Jose
Keyword(s):  
Magnetic Field ◽  
Mr Damper ◽  
Fast Response ◽  
Damping Force ◽  
Clear Fluid ◽  
Carrier Fluid ◽  
Fluid Turbulence ◽  
Mr Fluids ◽  
And Performance ◽  
Magneto Rheological

Abst r a c t -Magneto rheological aqueous is an old advancing to the bazaar at top speed. Excellent appearance like fast response, simple interface amid electrical ability ascribe and automated ability output, and absolute controllability accomplish MRF technology adorable for abounding applications.The aim of this project is preparation of MR-fluids by using the different types of carrier fluid mixed with iron powder and stability and magnetic properties are analysed. Thesedimentation of iron particles can be reduced by using additives. The sedimentation can be analysed by boundary variation of the clear fluid to the fluid turbulence. The viscosity of smart fluid can be increased by varying the applied magnetic field.The performance of the MR-damper depends on the applied maximum magnetic field and the hydraulic circuit design. The MR-damper force by increasing the magnetic field can be analysed by sing the FEMM V4 Software.Damping force depends on the excitation of current and magnetic field.Key words: Rheological, magnetic field, damping force, FEMM, flux density

scholarly journals Role of Magnetorheological Fluids and Elastomers in Today’s World

2017 ◽  
Vol 11 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Paweł Skalski ◽  
Klaudia Kalita
Keyword(s):  
Magnetic Field ◽  
Automotive Industry ◽  
Smart Materials ◽  
Magnetorheological Fluids ◽  
Magnetorheological Elastomer ◽  
Shock Absorbers ◽  
Damping Control ◽  
Mr Fluids ◽  
High Tension

AbstractThis paper explains the role of magnetorheological fluids and elastomers in today’s world. A review of applications of magnetorheological fluids and elastomers in devices and machines is presented. Magnetorheological fluids and elastomers belong to the smart materials family. Properties of magnetorheological fluids and elastomers can be controlled by a magnetic field. Compared with magnetorheological fluids, magnetorheological elastomers overcome the problems accompanying applications of MR fluids, such as sedimentation, sealing issues and environmental contamination. Magnetorheological fluids and elastomers, due to their ability of dampening vibrations in the presence of a controlled magnetic field, have great potential present and future applications in transport. Magnetorheological fluids are used e.g. dampers, shock absorbers, clutches and brakes. Magnetorheological dampers and magnetorheological shock absorbers are applied e.g. in damping control, in the operation of buildings and bridges, as well as in damping of high-tension wires. In the automotive industry, new solutions involving magnetorheological elastomer are increasingly patented e.g. adaptive system of energy absorption, system of magnetically dissociable [hooks/detents/grips], an vibration reduction system of the car’s drive shaft. The application of magnetorheological elastomer in the aviation structure is presented as well.

THE ANALYSIS OF THE WORKING CONDITIONS OF A THRUST SQUEEZE BEARING WITH A MAGNETORHEOLOGICAL FLUID OPERATING IN THE OSCILLATORY COMPRESSION MODE

Tribologia ◽  
2019 ◽  
Vol 285 (3) ◽  
pp. 45-50
Author(s):  
Wojciech HORAK ◽  
Marcin SZCZĘCH
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Rheological Properties ◽  
Working Conditions ◽  
Axial Force ◽  
Magnetorheological Fluid ◽  
Magnetorheological Fluids ◽  
Operating Characteristics ◽  
Carrier Fluid ◽  
Load Conditions

The operating state of thrust plain bearings is a function of many parameters, both geometric and related to load conditions. Besides the methods of controlling bearings of this type used so far, new possibilities of modelling their operating characteristics by using substances with controlled rheological properties as a lubricant can be pointed out. Magnetorheological fluids create such a possibility. These are suspensions of particles with magnetic properties in a carrier fluid (usually in mineral or synthetic oil). The influence of magnetic field on this type of fluids changes their rheological properties. This process is almost instantaneous and fully reversible. The paper presents the results of investigations of a thrust squeeze bearing lubricated with magnetorheological fluid. The aim of the study was to determine the influence of selected factors on the axial force as a result of the oscillatory squeeze load.

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