kannan k vijayan
TRANSCRIPT
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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