SMART MATERIALS AND SYSTEMS

1. SMART MATERIALS
AND SYSTEMS
BY
JOBIN JOY
ASSISTANT PROFESSOR
DEPARTMENT OF ME
SBCE

2. SCIENTIFIC ACHIEVEMENTS THAT
THE WORLD HAS MADE SINCE THE
BEGINNING OF HUMAN CIVILIZATION
• Up to 1760-:Very little scientific activity
• 1769 -:James watt invented steam engine.
• 1800-1900-:Age of industrialization
• 1900-2000-:Age of information
• After 2000-: Age of decision

3. SMART MATERIALS-WHY THIS NAME?
SMART
1. Suggesting
vigour,speedy,spirited,lively
2. Showing mental alertness and
INTELLIGENT
1. To perceive ones environment
2. To know/comprehend and learn
3. To understand
quickness of
4. To foresee problems
perception,shrewd,resourceful
5. To think abstractly.
3. Sharp

4. DESIRABLE ATTRIBUTES OF A
SYSTEM
Smart,
Intelligent
sense-able,
adaptive,
organic,
controlled
Material,
structures,
systems,
products
24
combinations

5. SMART SYSTEMS-DEFINITION
• Integration of functions( Sensor , Actuator and
Control mechanisms)
• Stimulus
• Response
A system which has intrinsic
sensor, actuator and control
mechanisms whereby it is capable
of sensing a stimulus, responding
it and reverting to its original state
after the stimulus is removed

6. SMART MATERIAL-DEFINITION
• Material which has the intrinsic or extrinsic
capabilities to respond to an external stimulus
in a functionally useful manner.
• E.g. : Zinc oxide varistors (ZNO)

7. SMART MATERIALS-EFFECTS
• Also called functional materials
• A material can be considered smart when a
input stimulus of a variable changes the
output of other variables not given as input
OR
A material is smart if a specific response is
produced to a combination of inputs.

8. SMART MATERIALS-EFFECTS
• Actuator effect (Converse effect)
Electrical,
thermal,
optical,
magnetic
input
Mechanical
action

9. SMART MATERIALS-EFFECTS
SENSOR EFFECT(DIRECT
EFFECT)
Electrical
signal
Mechanical
input

10. MAIN ADVANTAGES RESPECT
TO TRADITIONAL COMPONENTS
a) act simultaneously as sensors and
actuators
b) Perform controlled mechanical action
without any external mechanisms
c) Are adaptive with the environmental
conditions
d) High level of miniaturization
e) New functions development

11. SMART SYSTEMS-DEFINITION
• SMART STRUCTURE
A smart structures integrates the properties
of embedded sensors, actuators and control
mechanisms in order to respond to a given
stimulus in a functionally useful manner.
Usually
this
involves
implementing
hardware and or software control
mechanisms.

12. Need for smart systems
i. Optimizing response of large complex
systems
ii. Perform enhancements otherwise not
possible
iii. Functionality

13. SCHEMATIC OF A SMART STRUCTURE
STRUCTURE
FORCE
ACTUATOR
SENSOR
DISTURBANCE
CONTROLS
CONTROLLER

14. IDEAL SMART STRUCTURE
SENSOR-SKIN/NERVES
•
Distributed and integrated
•
Sense temperature, humidity stress,force,pressure etc
ACTUATOR-MUSCLES/NERVES
•
Distributed and integrated
•
Generate shape, force and motion
•
Change stiffness and damping level.
DECISION /CONTROL-SERVES/GENETICS
•
Distributed/hierarchical
•
Local level decision/actuation
•
High level communication with brain
ADDITIONAL FEATURES
•
Self breeding
•
Self healing/repairing
•
Self diagnosis

15. COMPARISON WITH BIOLOGICAL
STRUCTURES
•
•
•
•
Useful strength to weight ratio
Self repairing systems
Adaptive joining mechanisms(mainly muscles and tendons)
Processing is distributed with central monitoring
systems(brain)
• Communication channels throughout the systems(neurons)
• Central processor is highly adaptive and self configures in the
light of experience
• Energy transfer mechanisms involve chemically burned
distribution systems.

16. SMART SYSTEMS RESEARCH
• Smart systems is a multidisciplinary area
requiring understanding of
 Materials
 Electronics
 Signal processing
 Control

17. SMART MATERIAL RESEARCHUNDERSTANDING OF DIFFERENT DOMAINS
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
Mechanics and structurures
Control and processing
MEMS
Electro mechanics
Dynamics and vibrations.
Materials and systems.
Computer hardware and software.
Mathematics.
Manufacturing and quality control.
Design optimization
Mechatronics

18. SMART SYSTEMS EXPERTISE
SYSTEMS
ENGINEERING
MATERIAL
SCIENCE
APPLIED
PHYSICS
SMART SYSTEMS
ELECTRICAL
ENGINEERING
MECHANICAL
ENGINEERING

19. WHAT CONSTITUTES A SMART SYSTEM
• Mechanical structures
• Sensors
• Actuators
• Controllers
• Signal processing and data reduction

20. Components of smart system
SENSOR
•
To monitor environment changes and generate signals proportional to the
changing measurand
ACTUATOR
•
The actuators are used to change the properties of the smart structure in
order to achieve the desired response
CONTROL SYSTEM
•
The control system continuously monitors the sensors signal, processing
the information in order to determine if action is required ,if an action is
required then a signal is applied to the appropriate actuators.

21. SMART STRUCTURES CLASSIFICATION
• PASSIVELY SMART (eg:fibre optic sensor)
• Structures have the ability to respond to a stimulus in a
useful manner without assistance of electronic controls
or feedback systems.
•
ACTIVELY SMART.
• Structures utilize feedback loops which accelerate the
recognition and response process.
•
VERY SMART(OR INTELLIGENT).
• Structures utilize the nonlinear property of the
sensor,actuator,memory and or feedback systems to
tune the response behavior

22. Actuators consideration
• A number of different actuators can be
incorporated into a smart structure in order to
generate the appropriate response to a
detected environmental variation. This type of
actuator is dependent on a number of
parameters.

23. •
NATURE OF ACTUATION
• Optical,magnetic,thermal,mechanical,
• chemical etc.
•
NATURE OF DRIVING AGENCY
• Thermal,magnetic,electrical,chemical etc
•
ENVIRONMENTAL CONSIDERATIONS
• Corrosion,thermal,magnetic,electrical etc

24. •
•
•
•
INTERFACING
Size,geometry,mechanical properties etc.
PROPERTIES OF THE ACTUATOR
Displacement, force
generation,hysteresis,response time,
bandwidth etc.

25. SENSOR CONSIDERATION
• A number of different sensors can be
incorporated into a smart structure to
measure a number of different environmental
variations.the type of sensor utilized in smart
structures is dependent on a number of
factors.

26. SENSOR CONSIDERATION
• NATURE OF MEASURAND
• Radiation,magnetic,thermal,mechanical,chemical etc
• SENSOR OUTPUT
• Thermal,magnetic,electrical,optical mechanical etc
• ENVIRONMENT
• Corrosive,thermal,magnetic,electrical etc

27. SENSOR CONSIDERATION
• INTERFACING
• Size,geometry,mechanical properties
• OPERATIONAL PROPERTIES
• Sensitivity,bandwidth,linearity,gauge length,
operational range etc.

28. Smart control system
• The smart control system will provide
feedback control for the sensors and
actuators
• The scs will include the interfaces necessary
for the operation of the subsystem modules.

29. SMART CONTROL SYSTEM
THE SCS WILL CONSIST OF THE FOLLOWING
• Analogue to digital and digital to analogue
converters.
• Input signal amplification and filtering.
• Control algorithm.
• Digital signal processing(DSP)
• Output power supply.

30. APPLICATION OF SMART SYSTEMS
• Aerospace
• Defence
• Automotive
• Industrial
• Medical
• Civil

31. SMART MATERIAL TYPES
• Piezoelectric materials
• Optical fibers
• Shape memory alloys (SMA)
• Electro active materials
• Electro magneto rheological fluids
• Carbon Nanotubes

32. PIEZOELECTRIC MATERIAL
• It possesses the property of converting
mechanical energy into electrical energy and
vice versa.

33. Piezoelectric materials
• Mechanical stress
electrical field
Potential field : SENSOR(DIRECT EFFECT)
• Electric field
mechanical strain
ACTUATOR(CONVERSE EFFECT)

34. PIEZOELECTRIC SENSOR
• When mechanical stresses are applied on the
surface,
electric
charges
are
generated
(SENSOR EFFECT)
• If those charges are collected on a conductor
that is connected to a circuit, current is
generated.

35. PIEZOELECTRIC ACTUATOR
• When electric potential (voltage) is applied to
the surface of the piezoelectric material,
mechanical strain is generated (ACTUATOR)
• If the piezoelectric material is bonded to a
surface of a structure, it forces the structure
to move with it.

36. FORMS OF PIEZO MATERIALS
• 1-3 piezocomposites
• Active fiber composites
1. CRYSTALS
2. PZT(actuator material)
3. PVDF(sensing material)

38. FIBER OPTIC SENSORS
• Works on the principle of total internal reflection.
• All light energy will be completely reflected.
• It essentially sensor material. It cannot do any
actuation.
• When the system in which these fibers are
embedded undergoes any change, then the
incident wave length of the light undergoes a
physical shift, which indicates the change the
system.

39. COMPONENTS OF FIBER OPTIC SENSOR
a) Source of light
b) Length of sensing fiber
c) Photo detector
d) Demodulator
e) Processing and display optics
f) Electronics

40. TYPES OF FIBER OPTIC TYPES
BASED ON MODULATION OR DEMODULATION
• Phase sensor
• Frequency sensor
• Polarization sensor

41. BASED ON APPLICATION OF FOS
• Physical sensor
• Chemical sensor
• Biomedical sensor

42. MODE OF SENSING
• Extrinsic sensor
• Intrinsic sensor

43. ELECTROSTRICTIVE MATERIALS
• Principle materials-LEAD MANGANESE
NIOBATE:LEAD TITANATE(PMN-PT)
• LEAD LANTHANUM ZIRCONATE TITANATE(PLZT)
• This is used for actuation purpose only.
• Suitable for frequencies up to 50khz
• E=700GPA and very brittle
• Fast response time.
• Low hysteresis loop and hence low loss material.

44. MAGNETOSTRICTIVE MATERIALS
• Eg:TERFENOL-D (alloy of Terbium, iron(FE))
• Phenomenon similar to electrostriction
• Can be used for both sensing and actuation
• Rarest of the rare earth material. and hence very expensive
• Large strain levels(2%)
• E=200gpa and length of 200mm.
• Narrow hysteresis loop and hence low loss
• Generates large actuating force(order of kilonewtons)

45. SHAPE MEMORY ALLOY (SMA)
• Change mechanical properties with the
change of temperature
• Regain its original shape when heated
• Normal temperature-one phase
• Temp increases-changes its phase and retains
the memory.
• Main disadvantage is slower response time

46. SHAPE MEMORY ALLOYS(SMA)
•
•
•
•
•
•
made by nixing nickel and titanium
T<TC, Martensitic phase-plastic state-large strains can be
applied with little stress.
T>TC, Austenitic phase-memory phase-retains its original
shape.
Actuation is caused by transforming the material from
martensite to austenitic phase. This process causes enormous
amount of stress, which can be used for actuation purpose.
Slow reaction time
Properties depend on the composition, the phase and past
history.

47. ELECTRO-RHEOLOGICAL FLUID.
(ER FLUID)
• Viscous properties are modified by applying electric fields
• Obtained by mixing SILICONE OIL AND CORN STARCH.
• In the neutral state particles are uniformly distributed.
Under electric field the large dielectric constants
redistributes the particles changing the viscous properties.
• E R fluid are non Newtonian fluids.
• Useful in transforming shear stresses

48. ER FLUID
ELECTRIC FIELD
APPLIED
• ELECTRIC
FIELD
REMOVED
ER
FLUID
ER FLUID
CHANGES LIQUID TO
SOLID
CHANGES FROM
SOLID TO LIQUID

49. MAGNETO RHEOLOGICAL FLUIDS
(MR FLUID)
• LITHIUM GREASE MIXED WITH MICRON SIZED IRON
PARTICLES.
• Externally applied magnetic field in a direction normal to
the fluid flow direction from dipoles in the iron particles.
• Magnetic poles start attracting each others to the
direction of the field hence forming chains.
• The chains then form a skeleton within the fluid, which
gains the fluid controllable yield stress.

50. MR FLUID
MAGNETIC
FIELD APPLIED
• MAGNETIC
FIELD
REMOVED
MR
FLUID
MR FLUID
CHANGES TO LIQUID
TO SOLID
CHANGES FROM
SOLID TO LIQUID
This property can be used in changing the damping characteristics
of a damper

51. THANK YOU