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PANKAJRoll no. 09161010M.TECH.(IPD&M)
Dept. of mechanical engg.& tech.
Guru Jambheshwar university of science & technology (Hisar)
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INTRODUCTIONa. Smart Materialsb. Smart Systems
c. Dumb Materials & Biomimetics
CONTENTS
Types of smart materials
Examples of Biomimetics
Examples of Smart systems
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SMs referred to materials having functions such assensibility, micro processing and actuation
IntelligentMaterials
Senses a stimulus (eyes).
Takes an intelligent decision (brain).
Through electronic feedback it takes
corrective/preventive measures to avoidcatastrophic situations (arm).
One oftheemergingmaterialsintodays
developments ofmaterialS&T
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Concept indicate few more special functions which arenot being found in traditional structural materials
Comprises smart materials
comprises of basic components sensor, actuator andControl unit
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Dumb materials have been preprocessed and/or designed to offeronly a limited set of responses to external stimuli.
inspiration rather than imitation
design inspired by nature
Dumb materials and structures contrast sharply with the natural
world where animals and plants have the clear ability to adapt totheir environment in real time
Biomimetics
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pine-cone model
adapts to changing
temperaturesby opening when warm or
shutting tight if cold
Example of Biomimetics
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special alignment and grooved structureof tooth-like scales embedded in shark skin decrease
drag and thus greatly increase swimming proficiency
Airbus fuel consumption down 1% when shark
skin coating applied to aircraft
EXAMPLES OF BIOMIMETICS
Drag reduction byshark skin
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Lotus effect
most efficient self-cleaningplant= great sacred lotus
mimicked in paints and
other surface coatings
pipe cleaning in oil refineries
(Norway)
EXAMPLES OF BIOMIMETICS
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Types of Smart Materials
1. Shape memory alloys.
2. Piezoelectric materials
3. Magnetostrictive and
Electrostrictive materials
4. Active fluids
5. Ph and temperature
sensitive polymers.
6. Optical fibres
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TWO TYPES OF COMMONEFFECTS ARE:
1) ONE WAY EFFECT
2) TWO WAY EFFECT
SHAPE MEMORY ALLOY
a) INITIAL STATEb) DEFORMED SHAPE
c) HEATING
d) BACK TO ORIGINAL SHAPE
SMA is a material having ability to return to itsprevious shape after being deformed bytemperature changes or by just releasing thestress.
Example: Nitinol TiNi,copper-Zinc , copper -Tin
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Piezoelectric Materials
Piezoelectric Effects : Electric charge is created whenmaterial is mechanical stressed
Piezo = Pressure
Piezoceramics are the mostwidely used smart material
ApplicationsMedical Diagnostics.High frequency stereo-speakers.Computer Keyboards.Microphones.
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Magnetostrictive and Electrostrictive materials
Electrostrictive & Magnetostrictive: A swift , linear shape change ( expand or contract ) in response toan electric field/Magnetic field , instantly
Movement generated due to
forces b/w magnetic polesExpansion in presence ofelectric fields
ApplicationsHigh-power sonar transducers.
Motors., Hydraulic actuators.
Examples : Metglass, Terfenol-DLead magnesium niobiate
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ACTIVE FLUIDS
Applications Tunable dampers.
Vibration-isolation systems.
Clutches.
Brakes. Resistance Controls
Respond to an electric or a magnetic
field with a change in viscosity
Examples : Electrolytes , polar
fluids
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pH AND TEMPERATURESENSITIVE POLYMERS
pH-sensitive polymers are materials whichswell/collapse when the pH of the
surrounding media changes. Temperature-responsive polymers are
materials which undergo changes upon
temperature.
Used as surface modifiers , drug delivery
Examples :ethyl acrylamide (EAAm)
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OpticalFibres
Fibres that use intensity, phase, frequency orpolarization of modulation to measure strain,temperature, electrical/magnetic fields, pressure andother measurable quantities
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Smart Systems : AIR BAGS IN CARS
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Smart Systems
Locations of Potential Smart Systems in an
Aircraft
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Smart System : Smart Bridge
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The Future
The development of true smart materials at theatomic scale is still some way off, although theenabling technologies are under development.
Worldwide, considerable effort is being deployed to developsmart materials and structures. The technological benefitsof such systems have begun to be identified and,demonstrators are under construction for a wide range ofapplications from space and aerospace, to civil engineering
and domestic products
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