A NEW TREND IN TECHNOLOGYBY:SINGH VISWAJIT KUMAR

2SA10EE040

MAGNETO RHEOLOGICAL FLUIDS

CONTENTS

INTRODUCTION WORKING PRINCIPLEMODES OF OPERATION APPLICATIONS ADVANTAGES DISADVANTAGES FUTURE SCOPECONCLUSION

INTRODUCTION

WHAT IS A MAGNETO-RHEOLOGICAL FLUID? ?

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,

INTRODUCTION

magneto rheological shock absorber is a material 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.

A smart fluid is a fluid whose properties can be changed by applying an electric field or a magnetic field.

WORKING PRINCIPLE

WORKING: .

The magnetic particles which are typically micrometer or nano meter scale 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

Due to this magnetic flux viscosity of magneto rheological fluid gets increases and helps to reduce shock.

Thus it acts as a Bingham plastic.

MODES OF OPERATION

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 Devices using this mode of operation include servo-valves, dampers, shock absorbers and actuators.

MODES OF OPERATION

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

MODES OF OPERATION

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.

APPLICATIONS

Mechanical engineering Military and defense Optics Automotive Human prosthesis

ADVANTAGES

It can used in Dampers & shock absorber.

It is high quality fluid.

DISADVANTAGES

It is not insurmountable It is expensive.

Fluids are subject to thickening after prolonged use and need replacing.

FUTURE SCOPES

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

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.

REFRENCES

"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).

How Stuff Works "How Smart Structures Will Work"

Instant Armor: Science Videos - Science News – Science Central

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