Mod_1_smart_mat_lec_1.pdf

8/14/2019 Mod_1_smart_mat_lec_1.pdf

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Bishakh Bhattacharya & Nachiketa Tiwari

Indian Institute of Technology, Kanpur


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What is a Smart Material?

Smart systems using Smart

a er a sSmart Actuators

Direct and Reverse Effects

Piezoelectric Materials


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broadly known as Functional Materials.

The basic energy forms that gets interchanged are:thermal energy, electric energy, magnetic energy, sound

,function, self sensing, actuation & control

Smart sensors & actuators are highly embeddable


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Stu id Dumb Foolish Trivial Sensible

Smart/Clever Intelligent Wise

Present smart materials are in the range from highlysensible to poorly intelligent level

Passive smartness to Active Smartness; eg. of passive

smartness - multiphase rocket nozzle of Space Shuttle Porous Tungsten with silver coating, Graphite, Ceramic

ayer, ee

Passive smartness is in open-loop!


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.Traditional structures

Designed for certain performance requirements eg. load, speed,e span

Unable to modify its specifications if there is a change of

mar ruc ures

Can accommodate unpredictable environments Can meet exacting performance requirement

Offer more efficient solutions for a wide range of applications


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Piezoelectric film, PVDF SMA, Nitinol

,

MS Material, Terfenol-DSMA Nitinol


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y smar sensors an ac ua ors

Real time response

Better embeddability

Minimal effect on structural properties

Reduction in weight

Less power consumption

e er re a y


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Impetus to growth of smart

structures

Recent advances in materials

mprove sensor an ac ua or ec no og es

Real-time information processing

Tape casting and screen printing technologies


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Different Strategies for Vibration Control

(iv) Active Control

Additional Excitation

SOURCESYSTEM RESPONSE

Excitation

(i) Excitation reduction

at Source

(ii) System Modification

Energy Conversion

(v) Use response as a source of

excitation and convert mechanical

energy to electrical energy

(iii) Source isolation by using

vibration isolators, barriers or sound

absorbing materials

torage o nergy se or nergy

Scavenging Devices


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Smart Materials for Sensing & Actuation

Output Current/

Charge

Magne-

tization

Strain Temperature Light

In ut

Electric

Field

Cond-

uctivityPermitti-

Electro-

magneticEffect

Reverse

Piezo-electricity

Ohmic

Resistance

Electro-

Opticeffect

v ty

Magnetic

Field

Eddy

Current

Effect

Perme-

ability

Joule

Effect

Magneto-

Magneto

caloric Effect

Magnet

o-Optic

effect

Stress DirectPiezo-

Electric

Effect

VillaryEffect

ElasticModulus

Thermo-MechanicalEffect

Photo-elastic

Effect

Heat Pyro-

electric

Effect

Thermo-

Magne-

tization

Thermal

Expansion

Phase

Specific Heat Thermo-

Lumin-

ecence

Light Photo-

Voltaic

Effect

Photo-

Magne-

tization

Photo-

striction

Photo-

Thermal

effect

Refract-

ive

index


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Smart Materials as Sensors & Actuators

Direct Effect

Output

Stressu pu

Signal

Input Output Reverse Effect

Input:

/ Thermal


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Smart Actuators

Input Parameter Actuator Type/ Devices

Electric Field Piezoelectric/

Electrostrictiveec ros a c

Electro- Rheological Fluid

Magnetic Field MagnetostrictiveMagneto-Rheological Fluid

Chemical Mechano-chemical

Heat Shape Memory Alloy

ape emory o ymer

Light Photostrictive


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Drive Device Displacement Accuracy Torque/GenerativeForce

Response

Time

Air Pressure Motor Rotation degrees 50 Nm 10 sec

Cylinder 100mm 100m 10-1 N/mm2 10 secOil Pressure Motor Rotation degrees 1000 Nm 1 sec

Cylinder 1000mm 10m 100 N/mm2 1 secElectricity AC Servo Rotation minutes 30 Nm 100 msec

DC Servo Rotation minutes 200 Nm 10 msec

Linear Stepper 1000mm 10m 300 N 100 msec

Voice-Coil 1mm 0.1m 300 N 1 msecPiezoelectric 100m 0.01m 30 N/mm2 0.1 msec

Magnetostrictive 100m 0.01m 100 N/mm2 0.1 msec

Ultrasonic Motor Rotation minutes 1 Nm 1 msec


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All Piezoelectric Materials and PVDF

Magnetostrictive Materials Optical Fibre


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Ferroelectrics Perovskites, Piezoceramics,

PVDF respond to electric field by change inshape

Terfenol-D, Amorphous Met-Glasses show a

similar effect with the change in magnetic field Sha e Memor Allo res ond in a similar

manner but with the change in Thermal Field

electric/magnetic field by changing its viscosity


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Props. PZT PVDF T-D NiTiNOL

ree s ra n ppm

E. Mod. 62 2.1 48 27 M

(GPa) 89 - A

Band .1Hz-GHz .1Hz-GHz .1Hz-MHz 0-10 Hz


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Gauenzi, P., Smart Structures, Wiley,

2009 Cady, W. G., Piezoelectricity, Dover

,

Crawley, E. F., Intelligent Structures for

Aerospace: a technology overview and

-1699


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Mod_1_smart_mat_lec_1.pdf