The document discusses magneto-rheological (MR) fluids, which are suspensions of magnetizable particles in a carrier fluid. When exposed to a magnetic field, MR fluids increase dramatically in viscosity. They have applications in vibration dampers used to control structural vibrations. Key points: - MR fluids are composed of magnetizable particles like iron in an oil or silicone carrier fluid. - Applying a magnetic field causes the particles to form chains, increasing viscosity and damping force. - MR dampers use this property for vibration control and have advantages like high force capacity and mechanical simplicity. - Experiments show MR dampers can effectively reduce building displacement and acceleration during earthquakes. - Real world applications include bridges to reduce

1. Magneto-Rheological Fluid
Presented by
KANNAN K VIJAYAN
016
Guided by
Ms ARCHA GOPAN
Asst. Professor
CE Department

2. 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

3. discovered by jacob rabinow
MAGNETO RHEOLOGICAL FLUIDS
Belong to class of controllable fluids
Magnetizable and polarisable particle suspension
MR Fluids are used in Dampers
INTRODUCTION

4. 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.

5. Magneto Rheological Fluid
Particle size – 3 to 5 micron
 Concentration – 20% to 40%
 Specific gravity – 3 to 4

6. 20%-40% soft iron particles
Additives
 Discourage gravitational settling
 Promotes
Particle suspension
Lubricity
Viscosity
Inhibition of wear
COMPOSITION

7. EFFECT OF MAGNETIC FIELD

9. MRF-132LD  OIL-BASED
MRF-240BS  WATER BASED
MRF-336AG  SILICONE OIL BASED

11. MR DEVICES

12. Features of MR dampers
 Mechanical simplicity
 Large force capacity
 Robustness

13.  Valve mode
 Direct Shear mode
 Squeeze mode

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

15. 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

18. EXPERIMENT

19. Aim:
 To evaluate the effectiveness of semi-active control
strategies 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

22. 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

23. Advanced technology to protect city functions
Reduce damage caused due to earthquakes
Improves amenitiesof skyscrapers

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

25. REAL WORLD SITUATIONS
 Dong Ting lake bridge, China

26. Dong Ting lake bridge, China :
World’s first time implementation of MR damping
technique
312 MR dampers have been installed on the bridge
Suppresses wind-rain induced cable vibration
Installation of MR fluid shock absorbers-eliminated
resonance vibration

28. JOHN HANCOCK TOWER

29. TRANS-TOKYO BAY

30. 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

31. 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

32. 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 capacity
Low power requirement
Mechanical simplicity
 Can be scaled to sizes appropriate for civil engineering
applications

33. REFERENCES
1. 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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34. 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).
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