1) Magneto-rheological fluids are smart fluids whose viscosity increases greatly when subjected to a magnetic field, becoming nearly solid. Their viscosity and ability to transmit force can be precisely controlled by the magnetic field intensity.
2) MR fluids are made of magnetizable particles suspended in a carrier fluid. When a magnetic field is applied, the particles align and interact to increase viscosity.
3) Applications of MR fluids include vehicle suspensions, dampers, brakes, and prosthetic limbs, where their viscosity can be rapidly adjusted to control damping or resistance based on sensor inputs.
classify and explain various types of smart materials.
Smart materials” are materials that change significantly one or more of their properties, such as shape, color, or size in response to externally applied stimuli, such as stress, light, temperature, moisture or pH, and electric or magnetic fields.
classify and explain various types of smart materials.
Smart materials” are materials that change significantly one or more of their properties, such as shape, color, or size in response to externally applied stimuli, such as stress, light, temperature, moisture or pH, and electric or magnetic fields.
Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields.
The concept, application of Giant Magneto Resistance is being discussed in the slides
The discovery of this phenomenon has caused vast developments in the field of spintronics
Smart materials are now a days being used in all spheres of human life and technology. It have the functions of actuator, sensor, self-healing and so forth, are expected to be used not only as advanced functional materials but also as key materials to provide structures with smart functions. These are also called intelligent materials that has ability to respond to stimuli and environmental changes and to activate their function according these changes.
Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields.
The concept, application of Giant Magneto Resistance is being discussed in the slides
The discovery of this phenomenon has caused vast developments in the field of spintronics
Smart materials are now a days being used in all spheres of human life and technology. It have the functions of actuator, sensor, self-healing and so forth, are expected to be used not only as advanced functional materials but also as key materials to provide structures with smart functions. These are also called intelligent materials that has ability to respond to stimuli and environmental changes and to activate their function according these changes.
Magneto rheological fluids commonly known as MR fluids sometimes referred to as Ferro fluids are suspensions of solid in liquid whose properties changes drastically when exposed to magnetic field. Magneto rheological (MR) fluids are materials that respond to an applied field with a dramatic change in their rheological behavior. The essential characteristic of these fluids is their ability to reversibly change from a free-flowing, linear, viscous liquid to a semi-solid with controllable yield strength in milliseconds when exposed to a magnetic field. MR fluids find a variety of applications in almost all the vibration control systems. It is now widely used in automobile suspensions, seat suspensions, clutches, robotics, design of buildings and bridges, home appliances like washing machines etc. The key to success in all of these implementations is the ability of MR fluid to rapidly change its rheological properties upon exposure to an applied magnetic field. Magneto rheological (MR) fluids offer solutions to many engineering challenges. The success of MR fluid is apparent in many disciplines, ranging from the automotive and civil engineering communities to the biomedical engineering community. This well documented success of MR fluids continues to motivate current and future applications of MR fluid.
The design and simulation of magneto-rheological damper for automobile suspen...IJRES Journal
As the application of magneto-rheological (MR) damper in automobile suspension semi-active
control, according to the character of the MR fluid and the relations between the damping force of MR damper
and the structure parameters, the new-type automobile suspension MR damper was designed. At present, the
design method of MR damper is still depended on the experience of the designer, which can't be calculated
accurately. In this paper, after a review of the features and models of MR materials and devices, geometrical
design and magnetic circuit design of MR damper were presented and discussed in detail, then the performance
of MR damper was analyzed by MATLAB. Simulation results showed that the design method of this automobile
suspension MR damper was feasible and the test performance was satisfactory, which could meet the
requirements of damping system for automobile suspension and achieve the required adjustable range of
anticipative damping force.
Introduction to Magneto-Rheological Fluid Technology & Its Applicationijiert bestjournal
Magnetorheological (MR) fluid damper are semi active control device that have been applied
a wide range of practical vibration control application. In this study, the methodology adopted
to get a control structure is based on the experimental results. An Experiment has been
conducted to establish the behaviour of the MR damper. In this paper, the behaviour of MR
damper is studied and used in implementing vibration control. The force displacement and
force‐velocity response with varying current has been established for the MR damper. In this
paper we investigated theoretically at fabricated Magnetorheological damper by using
Magnetorheological fluid. Here MR fluid developed first by mixing of prepared nano size
(fe3o4) iron particle by co precipitation method. And a comparative study had done between
these iron particles prepared MR fluid. Here an experimental performed on fabricated MR
damper and discussed the behaviour of MR damper.
Smart fluid self adaptive damper system (sfsads)ijmech
This paper is on fluid damper systems, which is self-adaptive and used to increase the speed and acceleration of vehicles. In normal dampers there is a time lag leading to break in contact between the wheel and the road reducing the acceleration. Now, our idea is about making the suspension adapt to varying road conditions. Due to irregularities in asphalt, a change occurs in the suspension damper position with the aid of the magnetic field and causes the suspension to change from softer to harder and vice versa giving more acceleration and increasing the pace of the vehicle.
Investigation on Magnetorheological Damper for Its Various ApplicationsIJLT EMAS
Magneto Rheological damper is a special type of
damper that is filled with Magnetorheological fluids which can
be controlled by magnetic field using an electromagnet. These
types of smart fluids change their physical properties when
subjected to magnetic field and turn into visco-elastic solids in
few milliseconds. This property allows the MR damper to be
used as a shock absorber by controlling its damping
characteristics by changing the intensity of electromagnet. This
paper focuses on the various applications of MR dampers in
latest technologies
Stability Analysis of Journal Bearing Using Electro Rheological Fluid by Fini...ijsrd.com
in rotating machinery, the damping of structure which supports the rotating shaft has significant effect in machine vibration. Therefore by controlling the lubricant properties, the dynamic behavior of the system can be controlled. The objective of this paper is to study the dynamic behavior of a rotor supported by a journal bearing and fed with Electro-rheological (ER) fluid. ER fluids can be used to create ‘smart’ journal bearings & vibration controllers can be constructed to control the Stability of the ER fluid lubricated bearings. The ER fluid behaves like a Bingham fluid with a higher viscosity when electric field is applied, and restores its property when the field is removed. A reversible change in viscosity occurs in milliseconds with the electric field applied.
In our conventional electronic devices we use semi conducting materials for logical operation and magnetic materials for storage, but spintronics uses magnetic materials for both purposes. These spintronic devices are more versatile and faster than the present one. One such device is Spin Valve Transistors (SVT).
Spin valve transistor is different from conventional transistor. In this for conduction we use spin polarization of electrons. Only electrons with correct spin polarization can travel successfully through the device. These transistors are used in data storage, signal processing, automation and robotics with less power consumption and results in less heat. This also finds its application in Quantum computing, in which we use Qubits instead of bits.
NANOTECHNOLOGY IN HIGH YIELD STRESS SMART FLUIDS- A REVIEW.ijiert bestjournal
Electrorheological (ER) and Magnetorheological (MR) nano-fluids show dramatic and tunable changes in their rheological properties und er external magnetic or electric field strength respectively. These nano-fluids can be eff ectively incorporated in various engineering applications like shock absorber,dampe rs,clutches etc. The major problem to use these nano-fluids practically is their low y ield strength and problem of sedimentation. In this paper various smart nano-flu ids (ER & MR) have been studied. Special attention is given on development of stable,re-dispersible,durable,high yield stress smart nano-fluids with low sedimentation rat e. In this paper these nano-fluids are reviewed along with their rheological characteristi cs under external fields.
Viscoelastic response of polymeric solids to sliding contactsPadmanabhan Krishnan
A polymeric solid is seen to produce its own signatures in sliding contacts. This has immense applications. The viscoelastic phenomena and signatures are discussed with the relevant models.
plug in hybrid electrical vehicals seminar ppt by MD NAWAZMD NAWAZ
A 'gasoline-electric hybrid car' or 'Plug in hybrid electric vehicle' is a vehicle which relies not only on batteries but also on an internal combustion engine which drives a generator to provide the electricity and may also drive a wheel. It has great advantages over the previously used gasoline engine that drives the power from gasoline only. It also is a major source of air pollution. The objective is to design and fabricate a two wheeler hybrid electric vehicle powered by both battery and gasoline. The combination of both the power makes the vehicle dynamic in nature. It provides its owner with advantages in fuel economy and environmental impact over conventional automobiles. Hybrid electric vehicles combine an electric motor, battery and power system with an internal combustion engine to achieve better fuel economy and reduce toxic emissions.
In HEV, the battery alone provides power for low-speed driving conditions where internal combustion engines are least efficient. In accelerating, long highways, or hill climbing the electric motor provides additional power to assist the engine. This allows a smaller, more efficient engine to be used. Besides it also utilizes the concept of regenerative braking for optimized utilization of energy. Energy dissipated during braking in HEV is used in charging battery. Thus the vehicle is best suited for the growing urban areas with high traffic. Initially the designing of the vehicle in CAD, simulations of inverter and other models are done. Equipment and their cost analysis are done. It deals with the fabrication of the vehicle. This includes assembly of IC Engine and its components. The next phase consists of implementing the electric power drive and designing the controllers. The final stage would consist of increasing the efficiency of the vehicle in economic ways.
plug in hybrid electrical vehicals seminar report by MD NAWAZMD NAWAZ
A 'gasoline-electric hybrid car' or 'Plug in hybrid electric vehicle' is a vehicle which relies not only on batteries but also on an internal combustion engine which drives a generator to provide the electricity and may also drive a wheel. It has great advantages over the previously used gasoline engine that drives the power from gasoline only. It also is a major source of air pollution. The objective is to design and fabricate a two wheeler hybrid electric vehicle powered by both battery and gasoline. The combination of both the power makes the vehicle dynamic in nature. It provides its owner with advantages in fuel economy and environmental impact over conventional automobiles. Hybrid electric vehicles combine an electric motor, battery and power system with an internal combustion engine to achieve better fuel economy and reduce toxic emissions.
In HEV, the battery alone provides power for low-speed driving conditions where internal combustion engines are least efficient. In accelerating, long highways, or hill climbing the electric motor provides additional power to assist the engine. This allows a smaller, more efficient engine to be used. Besides it also utilizes the concept of regenerative braking for optimized utilization of energy. Energy dissipated during braking in HEV is used in charging battery. Thus the vehicle is best suited for the growing urban areas with high traffic. Initially the designing of the vehicle in CAD, simulations of inverter and other models are done. Equipment and their cost analysis are done. It deals with the fabrication of the vehicle. This includes assembly of IC Engine and its components. The next phase consists of implementing the electric power drive and designing the controllers. The final stage would consist of increasing the efficiency of the vehicle in economic ways.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
ML for identifying fraud using open blockchain data.pptx
Magneto rheological fluid
1. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 1
CHAPTER 1: INTRODUCTION
1.1Background
The properties of smart fluids have been known for around sixty years, but were subject to
only sporadic investigations up until the 1990s, when they were suddenly the subject of renewed
interest, notably culminating with the use of an MR fluid on the suspension of the 2002 model of
the Cadillac Seville STS automobile and more recently, on the suspension of the second-
generation Audi TT. Other applications include brakes and seismic dampers, which are used in
buildings in seismically-active zones to damp the oscillations occurring in an earthquake. Since
then it appears that interest has waned a little, possibly due to the existence of various limitations
of smart fluids which have yet to be overcome.
A magneto rheological fluid (MR fluid) is a type of smart fluid in a carrier fluid, usually
a type of oil. When subjected to a magnetic field, the fluid greatly increases its apparent
viscosity, to the point of becoming a viscoelastic solid. Importantly, the yield stress of the fluid
when in its active ("on") state can be controlled very accurately by varying the magnetic field
intensity. The upshot is that the fluid's ability to transmit force can be controlled with an
electromagnet, which gives rise to its many possible control-based applications. Extensive
discussions of the physics and applications of MR fluids can be found in a recent book.
MR fluid is different from a ferrofluid which has smaller particles. MR fluid particles are
primarily on the micrometre-scale and are too dense for Brownian motion to keep them
suspended (in the lower density carrier fluid). Ferrofluid particles are primarily nanoparticles that
are suspended by Brownian motion and generally will not settle under normal conditions. As a
result, these two fluids have very different applications.
A magneto rheological damper or magneto rheological shock absorber is a damper
filled with magneto rheological fluid, which is controlled by a magnetic field, usually using an
electromagnet. This allows the damping characteristics of the shock absorber to be continuously
controlled by varying the power of the electromagnet. This type of shock absorber has several
applications, most notably in semi-active vehicle suspensions which may adapt to road
conditions, as they are monitored through sensors in the vehicle, and in prosthetic limbs.
2. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 2
A smart fluid is a fluid whose properties can be changed by applying an electric field or
a magnetic field.
The most developed smart fluids today are fluids whose viscosity increases when a magnetic
field is applied. Small magnetic dipoles are suspended in a non-magnetic fluid, and the applied
magnetic field causes these small magnets to line up and form strings that increase the viscosity.
These magnetorheological or MR fluids are being used in the suspension of the 2002 model of
the Cadillac Seville STS automobile and more recently, in the suspension of the second-
generation Audi TT. Depending on road conditions, the damping fluid's viscosity is adjusted.
This is more expensive than traditional systems, but it provides better (faster) control. Similar
systems are being explored to reduce vibration in washing machines, air conditioning
compressors, rockets and satellites, and one has even been installed in Japan's National Museum
of Emerging Science and Innovation in Tokyo as an earthquakeshock absorber.
Some haptic devices whose resistance to touch can be controlled are also based on these MR
fluids.
Another major type of smart fluid are electrorheological or ER fluids, whose resistance to flow
can be quickly and dramatically altered by an applied electric field. Besides fast acting clutches,
brakes, shock absorbers and hydraulic valves, other, more esoteric, applications such as
bulletproof vests have been proposed for these fluids.
Other smart fluids change their surface tension in the presence of an electric field. This has been
used to produce very small controllable lenses: a drop of this fluid, captured in a small cylinder
and surrounded by oil, serves as a lens whose shape can be changed by applying an electric field.
3. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 3
1.1 MOTIVATION
Microrheology involves forcing probes externally and can be extended out of
equilibrium to the non linerar regime. Here we review the development, present state and
future directions of this field. We organise our review around the generalised stokes-
Einstein relation, which plays a central role in the interpretation of microrheology.
1.2 Motion control MR-Fluid
As motion control systems become more refined, vibration characteristics
become more important to a systems overall design and functionality engineers, however,
have tended to look at motion control and vibration as separate issues. Motion control, it
might be said, presents fairly familiar design engineering problems while vibration
suggests more subtle problems. Few design engineers have either the hands-on
experience or the training to address both sets of problems in a single design solution.
4. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 4
CHAPTER 2: WORKING PRINCIPLE
2.1 Working
Fig 2.1: Working
When a magnetic field is applied, however, the microscopic particles (usually in the 0.1–
10 µm range) align themselves along the lines of magnetic flux
2.2 Direction of magnetic flux
Fig 2.2: Direction of magnetic flux
To understand and predict the behavior of the MR fluid it is necessary to model the fluid
mathematically, a task slightly complicated by the varying material properties. As mentioned
above, smart fluids are such that they have a low viscosity in the absence of an applied magnetic
field, but become quasi-solid with the application of such a field. In the case of MR fluids, the
fluid actually assumes properties comparable to a solid when in the activated ("on") state, up
until a point of yield. This yield stress (commonly referred to as apparent yield stress) is
dependent on the magnetic field applied to the fluid, but will reach a maximum point after which
increases in magnetic flux density have no further effect, as the fluid is then magnetically
saturated. The behavior of a MR fluid can thus be considered similar to a Bingham plastic, a
material model which has been well-investigated.
However, a MR fluid does not exactly follow the characteristics of a Bingham plastic. For
example, below the yield stress (in the activated or "on" state), the fluid behaves as a viscoelastic
5. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 5
material, with a complex modulus that is also known to be dependent on the magnetic field
intensity. MR fluids are also known to be subject to shear thinning, whereby the viscosity above
yield decreases with increased shear rate. Furthermore, the behavior of MR fluids when in the
"off" state is also non-Newtonian and temperature dependent, however it deviates little enough
for the fluid to be ultimately considered as a Bingham plastic for a simple analysis.
Thus our model of MR fluid behavior in the shear mode becomes:
Where = shear stress; = yield stress; = Magnetic field intensity = Newtonian viscosity;
is the velocity gradient in the z-direction.
Low shear strength has been the primary reason for limited range of applications. In the
absence of external pressure the maximum shear strength is about 100 kPa. If the fluid is
compressed in the magnetic field direction and the compressive stress is 2 MPa, the shear
strength is raised to 1100 kPa. If the standard magnetic particles are replaced with elongated
magnetic particles, the shear strength is also improved.
Ferroparticles settle out of the suspension over time due to the inherent density difference
between the particles and their carrier fluid. The rate and degree to which this occurs is one of
the primary attributes considered in industry when implementing or designing an MR device.
Surfactants are typically used to offset this effect, but at a cost of the fluid's magnetic saturation,
and thus the maximum yield stress exhibited in its activated state.
These surfactants serve to decrease the rate of ferroparticle settling, of which a high rate is an
unfavorable characteristic of MR fluids. The ideal MR fluid would never settle, but developing
this ideal fluid is as highly improbable as developing a perpetual motion machine according to
our current understanding of the laws of physics. Surfactant-aided prolonged settling is typically
achieved in one of two ways: by addition of surfactants, and by addition of spherical
ferromagnetic nanoparticles. Addition of the nanoparticles results in the larger particles staying
6. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 6
suspended longer since to the non-settling nanoparticles interfere with the settling of the larger
micrometre-scale particles due to Brownian motion. Addition of a surfactant allows micelles to
form around the ferroparticles. A surfactant has a polar head and non-polar tail (or vice versa),
one of which adsorbs to a nanoparticle, while the non-polar tail (or polar head) sticks out into the
carrier medium, forming an inverse or regular micelle, respectively, around the particle. This
increases the effective particle diameter. Steric repulsion then prevents heavy agglomeration of
the particles in their settled state, which makes fluid remixing occur far faster and with less
effort. For example, magneto rheological dampers will remix within one cycle with a surfactant
additive, but are nearly impossible to remix without them.
While surfactants are useful in prolonging the settling rate in MR fluids, they also prove
detrimental to the fluid's magnetic properties, which is commonly a parameter which users wish
to maximize in order to increase the maximum apparent yield stress. Whether the anti-settling
additive is nanosphere-based or surfactant-based, their addition decreases the packing density of
the ferroparticles while in its activated state, thus decreasing the fluids on-state/activated
viscosity, resulting in a "softer" activated fluid with a lower maximum apparent yield stress.
While the on-state viscosity (the "hardness" of the activated fluid) is also a primary concern for
many MR fluid applications, it is a primary fluid property for the majority of their commercial
and industrial applications and therefore a compromise must be met when considering on-state
viscosity, maximum apparent yields stress, and settling rate of an MR fluid.
7. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 7
CHAPTER 3: MODES OF OPERATION
3.1 Flow mode
Fig 3.1: Flow mode
The fluid is located between a pair of stationary poles. The resistance to the fluid flow is
controlled by modifying the magnetic field between the poles, in a direction perpendicular to the
flow (Fig. 3.1). Devices using this mode of operation include servo-valves, dampers, shock
absorbers and actuators.
3.2 Shear mode
Fig 3.2 Shear mode
The fluid is located between a pair of moving poles (translation or rotation motion). The relative
displacement is parallel to the poles. The apparent viscosity, and thus the “drag force” applied by
the fluid to the moving surfaces can be controlled by modifying the magnetic field between the
poles. Devices using this mode of operation include clutches, brakes, locking devices
8. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 8
3.3 Squeeze-flow mode
Fig 3.3: Squeeze-flow mode
The fluid is located between a pair of moving poles. The relative displacement is perpendicular
to the direction of the fluid flow .The compression force applied to the fluid is varying
periodically. Displacements are small compared to the other modes but resistive forces are high.
As for the two other modes, the magnitude of these resistive forces can be controlled by
modifying the magnetic field between the poles. While less well understood than the other
modes, the squeeze mode has been explored for use in small amplitude vibration and impact
dampers.
3.4 Recent advances
Recent studies which explore the effect of varying the aspect ratio of the ferromagnetic particles
have shown several improvements over conventional MR fluids. Nanowire-based fluids show no
sedimentation after qualitative observation over a period of three months. This observation has
been attributed to a lower close-packing density due to decreased symmetry of the wires
compared to spheres, as well as the structurally supportive nature of a nanowire lattice held
together by remnant magnetization. Further, they show a different range of loading of particles
(typically measured in either volume or weight fraction) than conventional sphere- or ellipsoid-
based fluids. Conventional commercial fluids exhibit a typical loading of 30 to 90 wt%, while
nanowire-based fluids show a percolation threshold of ~0.5 wt% (depending on the aspect ratio).
They also show a maximum loading of ~35 wt%, since high aspect ratio particles exhibit a larger
per particle excluded volume as well as inter-particle tangling as they attempt to rotate end-over-
9. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 9
end, resulting in a limit imposed by high off-state apparent viscosity of the fluids. These new
ranges of loading suggest a new set of applications are possible which may have not been
possible with conventional sphere-based fluids.
Newer studies have focused on dimorphic magneto rheological fluids, which are conventional
sphere-based fluids in which a fraction of the spheres, typically 2 to 8 wt%, are replaced with
nanowires. These fluids exhibit a much lower sedimentation rate than conventional fluids, yet
exhibit a similar range of loading as conventional commercial fluids, making them also useful in
existing high-force applications such as damping. Moreover, they also exhibit an improvement in
apparent yield stress of 10% across those amounts of particle substitution.
Another way to increase the performance of magneto rheological fluids is to apply a pressure to
them. In particular the properties in term of yield strength can be increased up to ten times in
shear mode and up five times in flow mode. The motivation of this behaviour is the increase in
the ferromagnetic particles friction, as described by the semi empirical magneto-tribological
model by Zhang et al. Even though applying a pressure strongly improves the magneto
rheological fluids behaviour, particular attention must be paid in terms of mechanical resistance
and chemical compatibility of the sealing system used.
10. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 10
CHAPTER 4: APPLICATIONS OF MR-FLUID
The application set for MR fluids is vast, and it expands with each advance in the dynamics of
the fluid
4.1 Mechanical engineering
Magneto rheological dampers of various applications have been and continue to be
developed. These dampers are mainly used in heavy industry with applications such as heavy
motor damping, operator seat/cab damping in construction vehicles, and more.
As of 2006, materials scientists and mechanical engineers are collaborating to develop stand-
alone seismic dampers which, when positioned anywhere within a building, will operate within
the building's resonance frequency, absorbing detrimental shock waves and oscillations within
the structure, giving these dampers the ability to make any building earthquake-proof, or at least
earthquake-resistant.
4.2 Military and defense
The U.S. Army Research Office is currently funding research into using MR fluid to
enhance body armor. In 2003, researchers stated they were five to ten years away from making
the fluid bullet resistant. In addition, HMMWVs, and various other all-terrain vehicles employ
dynamic MR shock absorbers and/or dampers.
4.3 Optics
Magneto rheological finishing, a magneto rheological fluid-based optical polishing
method, has proven to be highly precise. It was used in the construction of the Hubble Space
Telescope's corrective lens.
11. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 11
4.4 Automotive
If the shock absorbers of a vehicle's suspension are filled with magneto rheological fluid
instead of a plain oil or gas, and the channels which allow the damping fluid to flow between the
two chambers is surrounded with electromagnets, the viscosity of the fluid, and hence the critical
frequency of the damper, can be varied depending on driver preference or the weight being
carried by the vehicle - or it may be dynamically varied in order to provide stability control
across vastly different road conditions. This is in effect a magneto rheological damper. For
example, the MagneRideactive suspension system permits the damping factor to be adjusted
once every millisecond in response to conditions. General Motors has developed this technology
for automotive applications. It made its debut in both Cadillac as "Magneride and Chevrolet
passenger vehicles (All Corvettes made since 2003 with the F55 option code) as part of the
driver selectable "Magnetic Selective Ride Control (MSRC)" system in model year 2003. Other
manufacturers have paid for the use of it in their own vehicles, for example Audi and Ferrari
offer the MagneRide on various models.
General Motors and other automotive companies are seeking to develop a magneto rheological
fluid based clutch system for push-button four wheel drive systems. This clutch system would
use electromagnets to solidify the fluid which would lock the driveshaft into the drive train.
Porsche has introduced magnetorheological engine mounts in the 2010 Porsche GT3 and GT2.
At high engine revolutions, the magnetorheological engine mounts get stiffer to provide a more
precise gearbox shifter feel by reducing the relative motion between the power train and
chassis/body.
4.5 Aerospace
Magnetorheological dampers are under development for use in military and commercial
helicopter cockpit seats, as safety devices in the event of a crash. They would be used to decrease
the shock delivered to a passenger's spinal column, thereby decreasing the rate of permanent
injury during a crash.
12. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 12
4.6 Human prosthesis
Magnetorheological dampers are utilized in semi-active human prosthetic legs. Much like
those used in military and commercial helicopters, a damper in the prosthetic leg decreases the
shock delivered to the patients leg when jumping, for example. This results in an increased
mobility and agility for the patient.
13. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 13
CHAPTER 5: ADVANTAGES & DISADVANTAGES
5.1 Advantages
Flow mode can we use in dampers and shock absorber.
Shear mode is particular useful in clutches and breaks and in place where rotational motion
must be controlled.
Switch flow mode is suitable for controlling small millimeter order movements.
Can be used in flow channels.
5.2 Disadvantages
Although smart fluids are rightly seen as having many potential applications, they are limited in
commercial feasibility for the following reasons:
High density, due to presence of iron, makes them heavy. However, operating volumes are
small, so while this is a problem, it is not insurmountable.
High-quality fluids are expensive.
Fluids are subject to thickening after prolonged use and need replacing.
Settling of ferro-particles can be a problem for some applications.
14. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 14
CHAPTER 6: FUTURE SCOPE & CONCLUSION
6.1 Future Scope
Mechanical engineering, Magneto rheological dampers of various applications have been
and continue to be developed. These dampers are mainly used in heavy industry with
applications such as heavy motor damping
materials scientists and mechanical engineers are collaborating to develop stand-alone
seismic dampers which, when positioned anywhere within a building, will operate within
the building's resonance frequency, absorbing detrimental shock waves and oscillations
within the structure, giving these dampers the ability to make any building earthquake-
proof, or at least earthquake-resistant.
The U.S. Army Research Office is currently funding research into using MR fluid to
enhance body armor
Can be used in the construction of the Hubble Space Telescope's corrective lens.
Magneto rheological dampers are under development for use in military and commercial
helicopter cockpit seats, as safety devices in the event of a crash
Magneto rheological dampers are utilized in semi-active human prosthetic legs.
6.2 Conclusion
future technology used in motor damping, operator seat/cab damping in construction
vehicles, and more
Ability to make any building earthquake-proof, or at least earthquake-resistant.
It was used in the construction of the Hubble Space Telescope's corrective lens.
Magneto rheological dampers are utilized in semi-active human prosthetic legs
15. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 15
REFERENCES
[1] Magnetorheology: Advances and Applications (2014), N.M. Wereley, Ed., Royal Society
of Chemistry, RSC Smart Materials, Cambridge, UK. DOI: 10.1039/9781849737548.
[2] "Mechanical properties of magnetorheological fluids under squeeze-shear mode" by
Wang, Hong-yun; Zheng, Hui-qiang; Li, Yong-xian; Lu, Shuang
"Physical Properties of Elongated Magnetic Particles" by Fernando Vereda, Juan de Vicente,
Roque Hidalgo-Álvarez
“Magnetorheology of submicron diameter iron microwires dispersed in silicone oil.” R.C.
Bell, J.O. Karli, A.N. Vavereck, D.T. Zimmerman. Smart Materials
“Influence of particle shape on the properties of magnetorheological fluids.” R.C. Bell, E.D.
Miller, J.O. Karli, A.N. Vavereck, D.T. Zimmerman. Journal of Modern Physics B. Vol. 21,
No. 28 & 29 (2007) 5018-5025.
“Elastic percolation transition in nanowire-based magnetorheological fluids.” D.T.
Zimmerman, R.C. Bell, J.O. Karli, J.A. Filer, N.M. Wereley, Applied Physics Letters, 95
(2009) 014102.
“Dimorphic magnetorheological fluids: exploiting partial substitution of micro-spheres by
micro-wires.” G.T. Ngatu, N.M. Wereley, J.O. Karli, R.C. Bell. Smart Materials and
Structures, 17 (2008) 045022.
"Study on the mechanism of the squeeze-strengthen effect in magnetorheological fluids " X.
Z. Zhang, X. L. Gong, P. Q. Zhang, and Q. M. Wang, J. Appl. Phys. 96, 2359 (2004).
A. Spaggiari, E. Dragoni "Effect of Pressure on the Flow Properties of Magnetorheological
Fluids" J. Fluids Eng. Volume 134, Issue 9, 091103 (2012).
HowStuffWorks "How Smart Structures Will Work"
Instant Armor: Science Videos - Science News - ScienCentral
16. Magneto-rheological fluids
SIET, VIJAYAPURA EEE DEPT Page 16
G.J. Hiemenz,Y.-T. Choi, and N.M. Wereley (2007). "Semi-active control of vertical
stroking helicopter crew seat for enhanced crashworthiness." AIAA Journal of Aircraft,
44(3):1031-1034 DOI: 10.2514/1.26492
N.M. Wereley, H.J. Singh, and Y.-T. Choi (2014). "Adaptive Magnetorheological Energy
Absorbing Mounts for Shock Mitigation." Magnetorheology: Advances and Applications,
N.M. Wereley, Ed., Royal Society of Chemistry, RSC Smart Materials, Cambridge, UK.
Chapter 12, pp. 278-287, DOI: 10.1039/9781849737548-00278.