2. INTRODUCTION: SMART MATERIAL
Common name for a wide group of different substances.
Having advanced properties compare to common materials.
One or more properties of common materials might be significantly
altered under controlled condition to get the smart materials.
Basically it’s a material that reacts quickly to a stimulus in a specific
manner.
The change in the material can also be reversible.
3. DEFINITION OF SMART MATERIALS
According to US Army Research Office, smart materials defined
as the following way
“ A system or material which has built in or intrinsic sensors,
actuators, and control mechanism whereby it is capable of
sensing a stimulus , responding to it in predetermined manner
and extent for appropriate time and reverting to its original state
as soon as the stimulus is removed”
4. HISTORY OF SMART MATERIALS….
In 1932 , the first recorded observation of smart material
transformation was made on gold-cadmium.
In 1938, the phase transformation was observed in brass (copper
zinc).
In 1962, the transformation and attendant shape memory effect in
Nickel-Titanium at the Naval Ordinance Laboratory.
After this, a number of other alloy systems with the shape memory
effect were found.
5. TRANSFORMATION MECHANISM OF SMART
MATERIAL
Smart materials exist as two stable phases under different
temperatures:
1. Austenite:- (i) High-temperature phase
(ii) Cubic crystal structure
6. CONTINUED….
2. Martensite :- (i) Low-temperature phase
(ii) Monoclinic crystal structure
In addition, there are two different forms of Martensite materials:
twinned and detwinned.
7. CLASSIFICATION OF SMART MATERIALS
Smart materials can be grouped into the following categories:-
1. Piezoelectric:-When subjected to an electric charge or a variation in
voltage, piezoelectric material will undergo some mechanical change,
and vice versa. These events are called the direct and converse
effects.
2. Electrostrictive:- This material has the same properties as
piezoelectric material, but the mechanical change is proportional to
the square of the electric field. This characteristic will always
produce displacements in the same direction.
8. CONTINUED….
3. Magnetostrictive :-When subjected to a magnetic field, material will
undergo an induced mechanical strain and vice versa. Consequently, it
can be used as sensors and/or actuators.
4. Shape Memory Alloys:- When subjected to a thermal field, this
material will undergo phase transformations which will produce shape
changes.
5. Optical Fibres:- Fibres it uses intensity, phase, frequency or
polarization of modulation to measure strain, temperature,
electrical/magnetic fields, pressure and other measurable quantities.
9. MODERN EXAMPLE OF SMART MATERIALS
Polymorph :- This is a unique polymer that fuses in hot water and
then it can be moulded to any form. When solid it has similar
properties to nylon.
Phosphorescent Sheet :- This is a sheet that absorbs light energy and
re-emits it as white light up to eight hours. Used extensively for
emergency lighting in the event of a power cut.
10. CONTINUED…..
Thermocolour Sheet :- This is a self adhesive sheet whose colour
changes according to the temperature. Used for thermometers, heat
warning patches and novelty advertising of products
11. CONTINUED….
Rigid PVC Foam Plastic :- This is a new generation of sheet material
used widely for signs and exhibitions. It is widely used for ‘plug and
yoke’ mouldings.
Quantum Tunnelling Composite (QTC) :-
12. ADVANTAGE W.R.T THE TRADITIONAL
MATERIALS
Act simultaneously as actuators and sensors
Perform controlled mechanical action without any external
mechanism
Are adaptive with the environmental condition
New function development
13. SMART MATERIAL RESEARCH UNDERSTANDING
OF DIFFERENT DOMAIN
Mechatronics
Design optimisation
Control and processing
Electro mechanics
Manufacturing
Dynamics and vibration
Materials and system
