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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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