Magneto-Rheological Fluid

Presented by

KANNAN K VIJAYAN016

Guided byMs ARCHA GOPANAsst. ProfessorCE Department

CONTENTS INTRODUCTION

MAGNETO RHEOLOGICAL FLUIDS

FLUID COMPOSITION

EFFECT OF MAGNETIC FIELD

MICRO SCOPIC VIEW

TYPES OF MR FLUID

EXPERIMENTS

REAL WORLD STRUCTURES

ADVANTAGES

DISADVANTAGES

CONCLUSION

REFERENCES

discovered by jacob rabinow

MAGNETO RHEOLOGICAL FLUIDSBelong to class of controllable fluidsMagnetizable and polarisable particle suspension

MR Fluids are used in Dampers

INTRODUCTION

WHAT ARE ‘MR’ FLUIDS?

Suspension of Particles made of a soft magnetic

material in a carrier oil. Carbonyl Iron Particles in Silicone Oil

A typical MR fluid contains 20–40% by volume of relatively

pure, soft iron particles,

Other Versions made out of Ceramics, or

Synthetic Polymers.

Magneto Rheological Fluid

Particle size – 3 to 5 micron

Concentration – 20% to 40%

Specific gravity – 3 to 4

20%-40% soft iron particles

Additives Discourage gravitational settling

PromotesParticle suspensionLubricityViscosityInhibition of wear

COMPOSITION

EFFECT OF MAGNETIC FIELD

MRF-132LD OIL-BASEDMRF-240BS WATER BASEDMRF-336AG SILICONE OIL BASED

MR DEVICES

Features of MR dampers

Mechanical simplicity Large force capacity Robustness

Valve mode Direct Shear mode Squeeze mode

Maximum damping force of 200,000N(20 tons) Outer cylinder - part of the magnetic circuit Damper is double-ended

Outer cylinder –part of the magnetic circuit

Electromagnetic coil-wound in three sections of piston

Ability to remain dormant for long

MR Fluid used-MRX-140ND

WORKING OF THE 20 TON LARGE SCALE MR FLUID

DAMPER

EXPERIMENT

Aim: To evaluate the effectiveness of semi-active controlstrategies using MR damper

Experiment: Scale model of the three storey prototype building used

Subjected to one dimensional ground excitation

MR damper employed-LORD SD-1000

Effectiveness of the semi-active control:

74.5% peak third floor displacement reduction

47.6%peak third floor acceleration reduction

Inference:

Result proves-Significance of MR technology in

structural vibration control

Advanced technology to protect city functionsReduce damage caused due to earthquakesImproves amenitiesof skyscrapers

Shock dampening units-placed in each floor Absorbs shocks –caused by quakes and windstorms

REAL WORLD SITUATIONS

Dong Ting lake bridge, China

Dong Ting lake bridge, China :World’s first time implementation of MR dampingtechnique

312 MR dampers have been installed on the bridgeSuppresses wind-rain induced cable vibrationInstallation of MR fluid shock absorbers-eliminatedresonance vibration

JOHN HANCOCK TOWER

TRANS-TOKYO BAY

ADVANTAGES Relatively straightforward in construction

The fluid becomes a semisolid and offers greater resistance than conventional, hydraulic shock absorbers

This shock absorber will eradicate the problems faced in the spring shock absorbers due to friction and other factors

DISADVANTAGE

These fluid compositions generally employ hydrocarbon and mineral oils as carrier fluids, which are obtained through complex processes.

Carrier fluids they employ are not available from renewable sources

The process for preparing these fluid compositions is complex

MR fluids: “Smart” materials with rheological properties

Properties can bealtered –exposure to magnetic field Higher yield stress than electrorheological fluids(ER

fluids)

MR Devices: Reasons for usage in structures for vibration control:

High force capacityLow power requirementMechanical simplicity

Can be scaled to sizes appropriate for civil engineeringapplications

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REFERENCES1. Amaratunga K. & Sudarshan R. “A Virtual Laboratory For Real- Time

Monitoring Of Civil Engineering Infrastructure”, International Conference On Engineering Education, Vol -2, 2003, (Pages:322-385).

2. Goel, R.K., “Performance of buildings during the January 26,2001 Bhuj Earthquake” ,EERI Special earthquake report April2001. (http://www.eeri.org/erthqukes/recon/bhug_india/engstruct.pdf.) Accessed January 5, 2007.

3. Hung E.S., and Zhao F., “Diagnostic Information Processing for Sensor Rich Distributed Systems”, Proceedings of. 3rd International Conference On Information Fusion, Sunnyvale, Canada., 2005, (Pages 27-33 & 55-58).

4. Roush W. “Networking the infrastructure”, Technology Review, December 2001,( Pages38-42).

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5. U.S. geological survey (USGS) “Monitoring Earthquake Shaking in Buildings to Reduce Loss of Life and Property”, 2007.

(http://geopubs.wr.usgs.gov/fact-sheet/fs068-03). Accessed January 22, 2007.

6. Yang G. ,“Large Scale Magneto rheological Fluid Damper for Vibration Mitigation: Modeling, Testing and Control”, 2005.

(http://cee.uiuc.edu/sstl/gyang2), Accessed December 12, 2006.

7. Yao J.T.P. and Spencer B.F., “Structural Control: Past, Present And Future”, Journal of Engineering Mechanics, Vol 123(9) , September 2004.

( Pages 5-42).

8. Yao J.T.P. and Soong T.T., “Structural Health Monitoring”, Journal of Engineering Mechanics, Vol 123(9) , September 2004.( Pages 55-59).

?ANY

QUESTIONS

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