The document discusses smart materials and their advantages over traditional materials. It begins by defining smart materials as materials that can sense environmental changes and respond in predetermined ways, similar to living organisms. Smart materials contain sensors to detect input signals and actuators to produce adaptive responses to changes like temperature, electric or magnetic fields. The document then compares traditional and smart systems, noting that smart systems can accommodate unpredictable environments, meet performance requirements more efficiently, and have applications in many fields. It provides tables contrasting properties of traditional technologies with new smart materials technologies.

1. i
A
SEMINAR REPORT
ON
SMART MATERIALS
SUBMITTED TO
MECHANICAL ENGINEERING DEPARTMENT
INSTITUTE OF ENGINEERING AND TECHNOLOGY
SUBMITTED BY
ASHISH JAISWAL
ROLL NO: 161391034018
UNDER THE SUPERVISION OF
ER. RAHUL SHUKLA
DEPARTMENT OF MECHANICAL ENGINEERING
INSTITUTE OF ENGINEERING AND TECHNOLOGY
BUNDELKHAND UNIVERSITY, JHANSI
SESSION 2019-20

2. ii
INSTITUTE OF ENGINEERING AND TECHNOLGY
BUNDELKHAND UNIVERSITY, JHANSI
DEPARTMENT OF MECHANICAL ENGINEERING
CERTIFICATE
This is to certify that the seminar report entitled, “SMART MATERIALS” has been
successfully submitted by ASHISH JAISWAL ( B.Tech ME 3RD year) Roll No:
161391034018, under my guidance in the partial fulfillment of requirement of Bachelor of
Engineering degree course in Mechanical Engineering, Bundelkhand University, Jhansi during
the academic year 2019-20.
DATE Er. Rahul Shukla
Seminar Incharge
Department of Mechanical Engineering
I.E.T. B.U. JHANSI

3. iii
ACKNOWLEDGEMENT
With immense please I, Ashish Jaiswal presenting “Smart Materials” seminar report as part of
the curriculum of Bachelor of Engineering. I wish to thank all the people who gave me unending
support, specially to Er. Rahul Shukla (Assistant Professor, Bundelkhand University, Jhansi)
for providing me the ample opportunity to present this seminar report in lucid manner by
providing proper guidance, support and efficient technical knowledge related to the topic. His
enthusiastic, noble and clear view on the format and layout of the report and presentation has helped
me a lot.
I am grateful to other faculty members specially, Er.Vishal Arya (Assistant Professor,
Bundelkhand University, Jhansi) for providing materials and knowledge related to topic.
Thanking You
ASHISH JAISWAL
B.Tech ME 3rd
Year
Roll no: 161391034018

4. iv
ABSTRACT
Smart materials are now a days being used in all spheres of human life and technology. It have
the functions of actuator, sensor, self-healing and so forth, are expected to be used not only as
advanced functional materials but also as key materials to provide structures with smart
functions. These are also called intelligent materials that has ability to respond to stimuli and
environmental changes and to activate their function according these changes. These stimuli may
be temperature, pressure, electric flow, magnetic flow, light, mechanical , etc can originate
internally or externally. They tell the structure to alter its properties to prevent damage, optimize
performance, correct malfunctions or alert users to a needed repair. A wide variety of smart
materials exist which includes piezoelectric materials, magneto rheological materials, electro
rheological materials, shape memory alloys. Smart materials find its application to wide areas
including aircrafts, computers, buildings, bridges, automobiles, etc.
Keywords: Smart materials, Piezoelectric, Electro rheological(ER), and magneto rheological
materials(MR)

5. v
CONTENT
Certificate ii
Acknowledgement iii
Abstract iv
List of Figures vi
Chapter No. Pages
1. Introduction 1-5
1.1. History
1.2. Approaches for developing Smart Materials
2. Smart Materials 6-8
2.1. Traditional v/s Smart system
2.2. Classification
2.3. Types
3. Piezoelectric materials 9-14
3.1. Constitutive Equation of Piezoelectricity
3.2. Direct piezoelectric effect
3.3. Converse piezoelectric effect
3.4. Preparation of Piezoceramic Actuator
3.5. Application
4. Magneto restrictive materials 15-17
4.1. Terfenol-D: A Magnetostrictive Smart Material
4.2. Magnetostrictive Transducer
4.3. Application
5. Smart Polymer 18-19
5.1. Active Smart Polymer(ASP)
5.2. Electro-active Polymers(EAP)
5.3. Classification of Electro-active Polymers
6. Shape Memory Alloys(SMA) 20-23
6.1. Manufacturing SMA Wires
6.2. Application
6.2.1. Space Application of SMA
6.2.2. A SMA based Sensor
7. Significance of Smart Materials 24-26
7.1. Future aspects of smart materials
8. Conclusion 27
9. References 28

6. vi
LIST OF FIGURES
Fig.1 Foldable wings of plane by use of smart materials 3
Fig.2 Cost study: Metal v/s Composite v/s Multifunctional Composite. 4
Fig.3 Common smart materials and associated stimulus-response 7
Fig.4 Piezoelectric–composite-based damping system 9
Fig.5 A piezo-composite for energy harvesting 12
Fig.6 Piezoelectric cable for energy harvesting of sea waves’ energy 14
Fig.7 Magnetostriction (e) in materials due to domain migration 15
Fig.8 TALON (Tactical Acoustic Littoral Ocean Network) sonar system 16
Fig.9 Generation of mechanical strain pulse by using current 17
Fig.10 Cartoon drawing of an EAP gripping device 19
Fig.11 Bending achieved in a prototype aircraft wing by heating of SMA
strips 20
Fig.12 SMA actuator variable geometry using SMA actuators by Boeing 22
Fig.13 A new shape memory alloy based smart encoder for sensing of
direction and angular motion 23

7. 1
CHAPTER 1: INTRODUCTION
Smart or intelligent materials are material that has to respond to stimuli and environmental
changes and to activate their function according these changes. The stimuli like a
temperature, pressure, electric flow, magnetic flow, light, mechanical etc can originate
internally or externally. Smart materials and related technologies have been drawing an
increasing amount of attention from researchers in related fields worldwide. In the past
decade, smart materials and structures has been one of the most progressive fields of
research. Recently developed materials and devices have been used to address many
challenges in aerospace, mechanical, bionics and medical technologies. The progress made
in developing advanced materials and devices is impressive and encouraging. The theme of
this special section is smart actuators and applications. This is one of the research areas of
smart materials and structures that is recognized as an essential aspect of smart
technologies. Therefore, we have organized this special section to promote the
development of technology as well as international communication in this field. In the
section, current progress in the field of smart materials and structures is presented. The
papers published cover the most recent research results in the development of several
different kinds of smart materials (e.g. fiber-reinforced shape memory polymer composites,
electro-rheological fluids, electro-active papers, shape memory alloys etc). In addition,
applications of the materials in smart structures are also included. We believe that the
papers published in this special section will be found to provide the latest information and
will encourage more researchers to make their contribution to this field of research.
1.1 History
The quest for superior capability in both civil and military products has been a key impetus
for the discovery of high performance new materials. In fact, the standard of living has been
impacted by the emergence of high performance materials. There is no doubt that the early
history of civilization is intertwined with the evolution of new materials. For example,
different eras of civilization are branded with their material capabilities, and these periods
are referred to as the Stone Age, the Bronze Age, the Iron Age, and the Synthetic Material
Age. The era saw an explosion of technological developments that touched every phase of
human endeavor. Most of the high performance engineering products, such as aerospace,
computers, telecommunication, and medical and power systems, were the result of the
development of advanced materials. This was an era of consolidation in terms of the
development of comprehensive design tools, material characteristics, and mechanics-based
analyses. During this period, the aerospace industry pioneered the development of
composite materials and structures that had direct impact on structural capability (e.g.,
specific strength and specific stiffness) as well as manufacturing and maintenance costs. This
translated into an increase in performance, payload, speed, range and a reduction in life-
cycle cost.

8. 2
The twenty-first century may be visualized as the Multifunctional Materials Age. The
inspiration for multifunctional materials comes from nature; hence, these are often referred
to as “bio-inspired materials.” This category encompasses smart materials and structures,
multifunctional materials, and nano-structured materials. This is a dawn of revolutionary
materials that may provide a “quantum jump” in performance and multi-capability. This
book focuses only on smart materials and structures. These are also referred to as
intelligent, adaptive, active, sensory, and metamorphic structures and materials and/or
systems. The purpose of these materials from the perspective of smart systems is their
ability to minimize lifecycle cost and/or expand the performance envelope. The ultimate
goal is to develop biologically inspired multifunctional materials with the capability to adapt
their structural characteristics (e.g., stiffness, damping, and viscosity) as required, monitor
their health condition, perform self-diagnosis and self-repair, morph their shape, and
undergo significant controlled motion over a wide range of operating conditions.
1.2 Approaches for developing Smart Materials
Development of smart materials and structures is possible through one of three approaches.
In the first approach, the new materials with smart functionality can be synthesized at the
atomic and molecular levels. Sometimes this is referred to as a nano-structured material. A
lot of the relevant methodology is hypothesized and is in an embryonic state at this time. In
the second approach, actuators and sensors are attached to a conventional structure that
adaptively responds to external disturbances. The actuators and sensors normally do not
constitute the load-carrying structure. Even though this is a relatively mature methodology,
it is not expected to be a structurally efficient scheme. In the third approach, active plies
representing actuators and sensors are synthesized with non-active plies to form a
laminated structure. A major drawback is that once the structure is cured, it is not possible
to replace nonfunctional plies. Even though this approach appears attractive in terms of
structural efficiency, there are issues related to the integrity of the system.
The key elements of smart structures are actuators, sensors, power conditioning, control
logics, and computers. Conventional displacement actuators are electromagnetic (including
voice coils), hydraulic, and servo- or stepper motors. The principal disadvantages of
conventional actuators are their weight, size, and slow response time. Their advantages are
their large stroke, reliability, familiarity, and low cost. Smart material actuators are normally
compact and change their characteristics under external fields such as electric, magnetic,
and thermal.

9. 3
Fig.1 Foldable wings of plane by use of smart materials
Typical smart material actuators are piezoelectric, electrostrictive, magnetostrictive, shape
memory alloys, and electrorheological/magnetorheological (ER/MR) fluids. Conventional
sensors are strain gauges, accelerometers, and potentiometers, whereas smart material
sensors can be fiber optics, piezoelectrics (ceramics and polymers), and magnetostrictives.
There is a wide variation of power requirements for different actuators. Key factors for a
power conditioning system are compactness, efficiency, and cost. For anefficient adaptive
system, the modeling and implementation of robust feedback control strategies are
important. A centralized, compact, and lightweight computer is vital to generate input
signals for actuators, perform system identification techniques with output data from
sensors, and implement control-feedback strategies. The basic idea of the synthesis of smart
structures appears to have been first conceptualized by Clauser in 1968. Seven years later,
Clauser himself demonstrated the concept . After this work, activity in this area started
increasing and grew rapidly in the 1990s. The historical development of key smart materials
is discussed first, followed by their applications in various industrial disciplines. Even though
the discovery of many of the smart materials took place during the past century, the
commercial availability, cost, and understanding of their behaviour have been major
impediments to their widespread use in commercial products. Today, one of the most
popular smart materials is polycrystalline piezoceramic, which exhibits strong piezoelectric
properties. Other popular smart materials include electrostrictives, magnetostrictives, shape
memory alloys, and ER/MR fluids.

10. 4
Besides system performance, the reduction in costs, at least in the post-production phase,
these composites could bring also something that should be taken into consideration (Fig. 2).
Fig. 2. Cost study: Metal v/s Composite v/s Multifunctional Composite.
Below is a detailed explanation for each component of the above figure.
 Raw material: It is to be expected that in most cases different materials will be used
in a MFMS, because that’s easier than to find a MFM that performs all the desired
functions. On the other hand, there are several hierarchical MS being developed, as
we will see, that increase material efficiency, thus using less material to achieve a
greater performance. It is then unclear where would MFMSs stand in terms of raw
material costs. Some may be cheaper others may be more expensive than current
materials, but either way, for the same price it is expected that the performance for
each function will increase, so the value will tend to get better.
 Fabrication: Currently manufacturing is one the greatest challenges in the production
of MFMS, and many methods used are expensive and haven’t been transferred to
industry because of difficulty in achieving scalability. It is to be expected that these
issues eventually subside, but still, since MFMS are of higher complexity than mono
functional ones, it might be the case that their production will also be more expensive

11. 5
and require more expensive tooling. On the other hand, with the increasingly
improving 3D-printing technology some of those difficulties may significantly reduce.
 Assembly: Assembly should be a clear winner for MFMS. Shape morphing
technologies and multi functionality reduce the number of articulated and external
components, which in turn reduce the number of parts and joining complexity. For
example, if one part made of a MFMS can do functions that used to need 5 different
materials/parts, then it’s a 5-fold decrease in joining operations.
 Maintenance: Maintenance is the area where MFMS should shine the most. Because
of their increasingly autonomous status, self-healing/sensing/regulating
(homeostasis)/etc., the need for human control should gradually decrease, and
therefore so should maintenance costs.
 Non-recurring: The fact that MFMS require an extensive knowledge often from a
wide range of fields, has to have some impact in the final cost of the material. The
design phase needs to integrate engineers from several fields as the material itself will
satisfy the requirements of several functions of different schools: electrical,
mechanical, biological, environmental, chemical, etc. Simulation software and
material databases should get more complex because of this reason.

12. 6
CHAPTER 2: SMART MATERIALS
Smart (or intelligent) materials are a group of new and state-of-the-art materials now being
developed that will have a significant influence on many of our technologies. The adjective
“smart” implies that these materials are able to sense changes in their environments and then
respond to these changes in predetermined manners— traits that are also found in living
organisms. In addition, this “smart” concept is being extended to rather sophisticated systems
that consist of both smart and traditional materials.
Components of a smart material (or system) include some type of sensor (that detects an
input signal),and an actuator (that performs a responsive and adaptive function). Actuators
may be called upon to change shape, position, natural frequency, or mechanical
characteristics in response to changes in temperature, electric fields, and/or magnetic fields.
2.1. Traditional v/s Smart system
Traditional system
• Designed for certain performance requirements e.g. load, speed, life span.
• Unable to modify its specifications if there is a change of environment.
Smart System
• Can accommodate unpredictable environments.
• Can meet exacting performance requirement.
• Offer more efficient solutions for a wide range of applications.
TRADITIONAL
TECHNOLOGIES
Stress
(Mpa)
Strain Efficiency Bandwidth
(Hz)
Work
(J/cm
2
)
Power
(J/cm
3
)
Electromagnetic 0.02 0.5 90% 20 0.005 0.1
Hydraulical 20 0.5 80% 4 5 20
Pneumatic 0.7 0.5 90% 20 0.175 3.5
Muscle 0.35 0.2 30% 10 0.035 0.35

13. 7
NEW
TECHNOLOGIES
Stress
(Mpa)
Strain Efficiency Bandwidth
(Hz)
Work
(J/cm
2
)
Power
(J/cm
3
)
Shape memory 200 0.1 3% 3 10 30
Electrostrictive 50 0.002 50% 5000 0.05 250
Piezoelectric 35 0.002 50% 5000 0.035 175
Magnetostrictive 35 0.002 80% 2000 0.035 70
Contractile polymer 0.3 0.5 30% 10 0.075 0.75
2.2 Classification
Smart materials can also be classified into two categories i.e., either active or passive.
Fairweather (1998) defined active smart materials as those materials which posses the
capacity to modify their geometric or material properties under the application of electric,
thermal or magnetic fields, thereby acquiring an inherent capacity to transducer energy.
Piezoelectric materials, SMAs, ER fluids and magneto- strictive materials are active smart
materials.
Smart materials, which are not active, are called passive smart materials. Although smart,
these lack the inherent capability to transducer energy. Fibre optic material is a good example
of a passive smart material. Such materials can act as sensors but not as actuators or
transducer.
Fig.3 Common smart materials and associated stimulus-response

14. 8
2.3 Types
a) Piezoelectric materials
b) Magneto restrictive materials
c) Active smart polymer
d) Shape memory alloy (SMA)

15. 9
CHAPTER 3: PIEZOELECTRIC MATERIALS
Piezoelectric materials are very common example of such materials where they produce a
voltage when stress is applied. Since this effect also applies in the reverse manner, a voltage
across the sample will produce stress within the sample. Suitably designed structures made
from these materials can therefore be made that bend, expand or contract when a voltage is
applied. They can also be used in optical-tracking devices, magnetic heads, dot-matrix
printers, computer keyboards, high-frequency stereo speakers, accelerometers, micro-phones,
pressure sensors, transducers and igniters for gas grills.
Fig.4 (a) A piezoelectric–composite-based damping system for a vertical fin of the F/A-18;
(b) MFC actuator for a small projectile fin; (c) it’s motion mimicking birds’ flight (d) A smart
flapping wing actuated by an MFC.
3.1 Constitutive Equation of Piezoelectricity
𝐷 = 𝑑𝑋 + 𝜀𝑋𝐸 Direct effect (Converts stress into electric potential)
𝑥 = 𝑆𝐸𝑋 +𝑑𝐸 Converse effect (Converts electric stimulus into strain)

16. 10
X – Stress (N/m2)
x- Strain
D - Electric displacement / flux density (C/m2)
S – Compliance (m2/N),
E - Electric field intensity (V/m or N/C) - Permittivity (F/m)
d - Piezoelectric constant (C/N or m/V)
Superscripts denote the measurement of permittivity at constant stress and compliance at
constant electric field intensity.
3.2 Direct piezoelectric effect
Compressive stress along the polarization direction
generates a voltage of the same polarity as the poling
voltage
Tensile stress along the polarization direction
generates a voltage of polarity opposite to that of the
poling voltage

17. 11
Compressive stress
perpendicularto polarization
direction generates a voltage of
opposite polarity to the poling
voltage
Tensile stress perpendicularto the
polarization direction generates a
voltage of the same polarity as the
poling volta
3.3 Converse piezoelectric effect
Effect of applied voltage on change in dimensions
Voltage of the same polarity as the poling
voltage causes an extension along the
poling direction and contraction
perpendicular to the poling direction

18. 12
Voltage of the opposite polarity as the
poling voltage causes a contraction along
the poling direction and extension
perpendicular to the poling direction
Fig.5 (a) A piezo-composite for energy harvesting (b) Schematic of a flexible hybrid energy
cell for harvesting from solar,
3.4 Preparation of Piezoceramic Actuator
• Start with fine powders of component metal oxides (PZT or Barium Titanate family) e.g..
for PZT you need PbO, ZrO2 and TiO2 powders.
• Mix them in fixed proportions.
• Use an organic binder.
• Form into specific shapes.
• Heat for a specific time and specified temperature 650800oC
• Cool – apply electrode (sputtering).
• Polarize the sensor/actuator using a DC electric field.

19. 13
3.5 Application
a) Bimorph: A bimorph is a cantilever used for actuation or sensing which consists of
two active layers. It can also have a passive layer between the two active layers. In
contrast, a piezoelectric unimorph has only one active (i.e. piezoelectric) layer and
one passive (i.e. non-piezoelectric) layer.
D31 Sensor
.
D31 Sensor
b) Piezostack: A piezo element is a ceramic that expands or contracts when an electrical
charge is applied, generating linear movement and force. Multiple piezo elements can
be layered on top of each other, creating what is known as a stacked piezo actuator.

20. 14
D33 Actuator
D33 Sensor
Fig. 6 Piezoelectric cable for energy harvesting of sea waves’ energy

21. 15
CHAPTER 4: MAGNETO RESTRICTIVE MATERIALS
Magical power of magnets awed people of early civilizations as a strange force from the
rocks that attracts shoes and swords without revealing itself! In 1842, James Prescott Joule
noted that a ferromagnetic sample changed its length with the application of Magnetism.
Magneto restrictive materials similar to piezoelectrics, respond to only magnetic fields rather
than electric. They are typically used in low-frequency, high-power sonar transducers, motors
and hydraulic actuators, along with the shape-memory alloy Nitinol, magneto restrictive
materials are considered promising candidates for achieving active damping of vibrations
Fig. 7 Magnetostriction (e) in materials due to domain migration and reorientation under
applied magnetic field H.
4.1 Terfenol-D: A Magnetostrictive Smart Material
Terbium – Iron (Fe) – Naval Ordinance Laboratory – Dysprosium (Terfenol-D)
It is an alloy of the formula TbxDy1−xFe2 (x ~ 0.3), is a magnetostrictive material. It was
initially developed in the 1970s by the Naval Ordnance Laboratory in United States. The
technology for manufacturing the material efficiently was developed in the 1980s at Ames
Laboratory under a U.S. Navy funded program. It is named after terbium, iron (Fe), Naval
Ordnance Laboratory (NOL), and the D comes from dysprosium.

22. 16
4.2 Magnetostrictive Transducer
It is a device that is used to convert mechanical energy into magnetic energy and vice versa.
Such a device can be used as a sensor and also for actuation as the transducer characteristics
is very high due to the bi-directional coupling between mechanical and magnetic states of the
material.
This device can also be called as an electro-magneto mechanical device as the electrical
conversion to its appropriate mechanical energy is done by the device itself. In other devices,
this operation is carried out by passing a current into a wire conductor so as to produce a
magnetic field or measuring current induced by a magnetic field to sense the magnetic field
strength.
Fig.8 TALON (Tactical Acoustic Littoral Ocean Network) sonar system
uses Magneto strictive Terfenol-D for under-water submarine detection

23. 17
4.3 Application
The applications of this device can be divided into two modes. That is, one implying Joule
Effect and the other are Villari Effect.
Fig.9 Generation of mechanical strain pulse by using current
 In the case where magnetic energy is converted to mechanical energy it can be used for
producing force in the case of actuators and can be used for detecting magnetic field in the
case of sensors.
 If mechanical energy is converted to magnetic energy it can be used for detecting force or
motion.
 In early days, this device was used in applications like torque meters, sonar scanning devices,
hydrophones, telephone receivers, and so on. Nowadays, with the invent of “giant”
magnetostrictive alloys, it is being used in making devices like high force linear motors,
positioners for adaptive optics, active vibration or noise control systems, medical and
industrial ultrasonic, pumps, and so on. Ultrasonic magnetostrictive transducers have also
been developed for making surgical tools, underwater sonar, and chemical and material
processing.

24. 18
CHAPTER 5: SMART POLYMER
Smart polymers or stimuli-responsive polymers are high-performance polymers that change
according to the environment they are in. Such materials can be sensitive to a number of
factors, such as temperature, humidity, pH, the wavelength or intensity of light or
an electrical or magnetic field and can respond in various ways, like altering colour or
transparency, becoming conductive or permeable to water or changing shape (shape memory
polymers). Usually, slight changes in the environment are sufficient to induce large changes
in the polymer's properties.
These are of two categories:
 Active Polymers that respond to input stimuli such as pH, magnetic field and light;
eg., PAC (Polyanionic cellulose)
 Electro-active Polymers that respond to the change of electrical input. Also known
as EAP.
5.1 Active Smart Polymer
Response to light due to Azobenzene groups, contain N=N double bonds.
Under visible light N=N bonds have a cis conformation - the polymer is bent.
Under UV light source the bonds become trans and the polymer flattens.

25. 19
5.2 Electro-active Polymers(EAP)
EAPs, are polymers that exhibit a change in size or shape when stimulated by an electric
field. The most common applications of this type of material are in actuators and sensors. A
typical characteristic property of an EAP is that they will undergo a large amount of
deformation while sustaining large forces.
Fig.10 (a) Cartoon drawing of an EAP gripping device.
(b) A voltage is applied and the EAP fingers deform in order to surround the ball.
(c) When the voltage is removed, the EAP fingers return to their original shape and grip the
ball.
5.2.1 Classification of Electro-active Polymers
EAPs (respond to electric stimulus) are broadly classified into two groups:
 Electronic EAP - Driven by electric field or coulomb forces.
 Ionic EAP - Change shape by mobility or diffusion of ions
Electronic EAP (EEAP) Ionic EAP (IEAP)
 Dielectric EAP  Ionic Polymer Gels (IPG)
 Electrostrictive Paper  Ionic Polymer Metal Composite
(IPMC) Nafion (DuPont, USA) &
Flemion (Asahi, Japan)
 Ferroelectric Polymers  Conducting Polymers (CP)
 Liquid Crystal Elastomer  Carbon Nanotubes (CNT)

26. 20
CHAPTER 6: SHAPE MEMORY ALLOY
Shape Memory Alloys (SMA) or shape memory polymers, are materials that can hold
different shapes at various temperatures. They can be deformed and returned to their original
shape by heating. In the process, they generate an actuating force. Shape memory alloy, such
as NiTiNOL, an alloy of nickel and titanium, which has a corrosion resistance similar to
stainless steel, making it particularly useful for biomechanical applications. Such types of
materials can be used in coffee-pot thermostat, super elastic spectacle frames, stents for veins,
whereas shape memory polymer has the ability to regain its original shape when heated.
These are generally used in biodegradable surgical sutures that will automatically tighten to
the correct tension and also in self repairing car bodies that will recover shape on gentle
heating after a dent.
Fig. 11 Bending achieved in a prototype aircraft wing by heating of SMA strips. (a) Un-
morphed and (b) morphed

27. 21
Metallic Alloys that show SME:-
• SME was first observed in 1932 in Gold Cadmium Alloy.
• Three types of SMA are currently popular
 Cu Zn Al
 Cu Al Ni
 Ni Ti (1962)
• The last one is commercially available as NiTiNOL. (NOL – Naval
Ordinance Laboratory, USA)
There are two common shape memory effect:-
• In the case of One Way effect, the material always remembers the shape at
Parent State (Austenite Phase).
• In the case of Two Way effect, the material is trained to remember two shapes,
one at the Parent Austenite phase and the other at the Martensite Phase.
6.1 Manufacturing SMA Wires
Shape Memory Alloy can be manufactured by following methods:-
• Shape memory alloys are typically made by casting, using vacuum arc melting
or induction melting.
• These are specialized techniques used to keep impurities in the alloy to a
minimum and ensure the metals are well mixed.
• The ingot is then hot rolled into longer sections and then drawn to turn it into
wire.
6.2 Application
Shape Memory Alloy finds wide area of application some of them are:-
6.2.1 Space Application of SMA
 Control of aerodynamic surfaces
 Micro-coils for vibration isolation
 Grasping by robotic fingers
 Space exploration: rock splitting
 Nitinol filter
 Deployment of Solar Array Hinges
 To optimize the acoustics and performance of a jet engine

28. 22
Fig.12 SMA Actuator Variable geometry using SMA actuators by Boeing
6.2.2 A SMA based Sensor
SMA wires with its high specific actuation energy density and its capability to be applied as
strain sensors are integrated in a polymer matrix. The design of such adaptive composites
with actuating functionality depends on anisotropic linear elastic and temperature-sensitive
stress-strain behaviour, thermal expansion coefficients, SMA phase transformation
temperatures and on contact surface interaction of the composite components.

29. 23
Fig.13 A new shape memory alloy based smart encoder for sensing of
direction and angular motion

30. 24
CHAPTER 7: SIGNICANCE OF SMART MATERIALS
Smart materials find a wide range of applications due to their varied response to external
stimuli. The different areas of application can be in our day to day life, aerospace, civil
engineering applications and mechatronics to name a few. The scope of application of smart
material includes solving engineering problems with unfeasible efficiency and provides an
opportunity for creation of new products that generate revenue. Important feature related to
smart materials and structures is that they encompass all fields of science and engineering. As
far as the technical applications of smart materials is concerned, it involves composite
materials embedded with fiber optics, actuators, sensors, Micro Electro Mechanical Systems
(MEMSs), vibration control, sound control, shape control, product health or lifetime
monitoring, cure monitoring, intelligent processing, active and passive controls, self-repair
(healing), artificial organs, novel indicating devices, designed magnets, damping aero elastic
stability and stress distributions. Smart structures are found in automobiles, space systems,
fixed-and rotary-wing aircrafts, naval vessels, civil structures, machine tools, recreation and
medical devices.
The kind of ‘smartness’ shown by these materials is generally programmed by material
composition, special processing, introduction of defects or by modifying the micro-structure,
so as to adapt to the various levels of stimuli in a controlled fashion. Like smart structures,
the terms ‘smart and ‘intelligent’ are used interchangeably for smart materials. Takagi (1990)
defined intelligent materials as the materials which respond to environmental changes at the
most optimum conditions and manifest their own functions according to the environment.
The feedback functions within the material are combined with properties and functions of the
materials.
Structures such as buildings, bridges, pipelines, ships and aircraft must be strongly designed
and regularly inspected to prevent ‘wear and tear’ damage from causing disastrous failures.
Inspection is expensive and time consuming, while designing to prevent damage can
compromise performance. With some modern materials, damage can be internally serious but
leave very little surface evidence.
Some common applications of smart materials in different fields are:-
a) Structural Health Monitoring
Embedding sensors within structures to monitor stress and damage can reduce
maintenance costs and increase lifespan. This is already used in over forty bridges
worldwide.
b) Self- Repair
When damage occurs, these tubes break, exposing the resin which fills any damage
and sets. Self-repair could be important in inaccessible environments such as
underwater or in space.

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c) In the Field of Defense and Space
Smart materials have been developed to suppress vibrations and change shape in
helicopter rotor blades. Shape-memory-alloy devices are also being developed that are
capable of achieving accelerated breakup of vortex waves of submarines and similarly
different adaptive control surfaces are developed for airplane wings. Besides, present
research is on its way to focus on new control technologies for smart materials and
design methods for placement of sensors and actuators.
d) In Nuclear Industries
Smart technology offers new opportunities in nuclear industrial sector for safety
enhancement, personal exposure reduction, life-cycle cost reduction and performance
improvement. However, the radiation environments associated with nuclear
operations represent a unique challenge to the testing, qualification and use of smart
materials. However, the use of such smart materials in nuclear facilities requires
knowledge about the materials respond to irradiation and how this response is
influenced by the radiation dose.
e) Biomedical Applications
In the field of biomedicine and medical diagnostics, still investigations are being
carried out. Certain materials like poly-electrolyte gels are being experimented for
artificial-muscle applications, where a polymer matrix swollen with a solvent that can
expand or contract when exposed to an electric field or other stimulation. In addition,
due to biodegradability of these materials, it may make it useful as a drug-delivery
system.
f) Health
Biosensors made from smart materials can be used to monitor blood sugar levels in
diabetics and communicate with a pump that administers insulin as required.
However, the human body is a hostile environment and sensors are easily damaged.
Some researches on barrier materials are going to protect these sensors.
Now-a-days different companies are developing smart orthopedic implants such as
fracture plates that can sense whether bones are healing and communicate data to the
surgeon. Small scale clinical trials of such implants have been successful and they
could be available within the next five years. Other possible devices include
replacement joints that communicate when they become loose or if there is an
infection. Current technology limits the response of these devices to transmitting data
but in the future, they could respond directly by self-tightening or releasing
antibiotics. This could reduce the need for invasive surgery.
g) Reducing waste
All over the world, the electronic wastes are the fastest growing components of
domestic waste. During disposal and processing of such wastes, hazardous and
recyclable materials should be removed first.

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Since manual disassembly is expensive and time consuming but the use of smart
materials could help to automate the process. Recently fasteners constructed from
shape memory materials are used that can self release on heating. Once the fasteners
have been released, components can be separated simply by shaking the product. By
using fasteners that react to different temperatures, products could be disassembled
hierarchically so that materials can be sorted automatically.
7.1 Future aspects of smart materials
The development of true smart materials at the atomic scale is still some way off, although
the enabling technologies are under development. These require novel aspects of
nanotechnology (technologies associated with materials and processes at the nanometer scale,
10-9m and the newly developing science of shape chemistry.
Worldwide, considerable effort is being deployed to develop smart materials and structures.
The technological benefits of such systems have begun to be identified and, demonstrators
are under construction for a wide range of applications from space and aerospace, to civil
engineering and domestic products. In many of these applications, the cost benefit analyses of
such systems have yet to be fully demonstrated.

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CONCLUSION
The technologies using smart materials are useful for both new and existing process and
technologies. Future application by adaptation of Smart Materials in civil engineering,
medicine, transportation, space and other areas can greatly boost the development and also
quality of life. Of the many emerging technologies available the few described here need
further research to evolve the design guidelines of systems.
Hence, it is matter of engineers and scientists, to work in this area, as it has a far-reaching
range of possible application and which pushes forward the technological paradigm in the
direction of the ideal future technology.

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REFERENCES
1) National Programme on Technology Enhanced Learning (NPTEL)
https://nptel.ac.in/courses/112104251/4
2) André Duarte B.L. Ferreira, Paulo R.O. Nóvoa, António Torres Marques
“Multifunctional Material Systems: A state-of-the-art review”
https://www.sciencedirect.com/science/article/pii/S0263822316000416
3) Harvinder Singh, Ramandeep Singh
“Smart Materials: New Trend in Structural Engineering”
http://www.ijari.org/CurrentIssue/2015Volume4/IJARI-ME-15-12-114.pdf
4) Prof. Parihar A.A., Ms. Kajal D. Khandagale, Ms. Pallavi P. Jivrag
“Smart Materials”
http://iosrjournals.org/iosr-jmce/papers/vol13-issue5/Version-6/D1305062832.pdf
5) Susmita Kamila
“Introduction, Classification and Applications of Smart Materials: An Overview”
https://thescipub.com/PDF/ajassp.2013.876.880.pdf
Books
1) William D. Callister, Jr.
“Materials Science and Engineering An Introduction”, 7th
Edison, John Wiley &
Sons, USA 2007.
2) Serope Kalpakjian, Steven R Schmid
“Manufacturing Engineering and Technology”, 7th
Edison, Pearson Publications,
Singapore 2014.