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HISTORY OF SHAPE MEMORY ALLOYS:
The first reported step towards discovery of shape
memory effect were taken in 1930’s according to Otsuka and Wayman In
a silver-cadmium alloy.
Shape memory polymers have also been developed and become
commercially available in late 1990’s.
INTRODUCTION:
Shape memory alloys or SMA's are metals that exhibit shape
memory properties.
It allows materials possessing shape memory properties to return to
their original shape after having suffered some form of deformation
after they are heated to temperatures above their transformation
temperature.
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Senses a stimulus (eyes).
Takes an intelligent decision (brain).
Through electronic feedback it takes
corrective/preventive measures to avoid
catastrophic situations (arm).
DEFINITION OF SMART MATERIALS:
Smart materials are materials that have one or more
properties that can be significantly changed in a
controlled fashion by external stimuli, such as stress,
temperature, moisture, ph, electric or magnetic fields.
1.
2.
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5.
Shape memory alloys
Piezoelectric materials
Magnetostrictive materials
Active fluids
Ph and temperature sensitive polymers.
1) SHAPE MEMORY EFFECTS
TWO TYPES OF COMMON EFFECTS ARE:
1)
ONE WAY EFFECT
2)
TWO WAY EFFECT
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ONE WAY EFFECT:
When a shape memory alloy is
in its cold state, the metal can be bent or
stretched and will hold those shapes until
heated above transient temperature. Upon
heating the shape changes to its original.

TWO WAY EFFECT:
A Material That Shows Shape
Memory Effect During Both Heating
And Cooling Is Called “Two Way
Shape Memory”
a)
b)
c)
d)
INITIAL STATE
DEFORMED SHAPE
HEATING
BACK TO ORIGINAL SHAPE
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Expand and contract with
the application of voltage.
Piezoceramics are the most
widely used smart material.
Applications
Ink Jet Printers.
Medical Diagnostics.
High frequency stereospeakers.
 Computer Keyboards.
 Microphones.
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Expand and contract with the application of
magnetic fields.
Applications
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High-power sonar transducers.
Motors.
Hydraulic actuators.
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Respond to an electric or a magnetic field with
a change in viscosity.
Applications
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Tunable dampers.
Vibration-isolation systems.
Clutches.
Brakes.
Resistance Controls
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pH-sensitive polymers are materials which
swell/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.
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Activate control inceptors using smart material
motion control.
Remove toxic pollutant from water.
Advanced liquid crystal display.
Artificial muscles.
Hydraulic fitting.
To determine the defects in buildings and
bridges.
To find stealth in aeroplanes and submarines.
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BIO-COMPATIBILITY
STRONG , CORROSIVE RESISTANT
PRODUCES VERY LARGE RECOVERY
STRESSES
MATERIAL IS DUCTILE
VERY EFFECTIVE FOR LOW FREQUENCY
VIBRATIONS
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Expensive to manufacture.
Slow reaction time.
Non linear thermo-mechanical behavior can
limit the accuracy.
Low energy efficiency conversion.
“ Smart materials” are just starting to emerge
from the laboratory but soon you can expect to
find them in everything from laptops to
concrete bridges.
PRESENTED BY :
ANANTH KR
SHIVARAJ N