International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
Generation of Mechanical Energy using a Nitinol Wire
By S. Swaroop Kumar1, Dr.S.A.K.Jilani2
Student (M.Tech In Micro And Nano Electronics), Madanapalle, India 1
Professor, Department Of Electronics &Communication Engineering, Mits, Madanapalle, India 2
ABSTRACT:
The main objective of this project is to develop an
innovative technology in order to generate
mechanical energy using simpler equipments and at
low cost variations.
In order to achieve the above objective we
need to study about certain unique properties of
SMA’s(Shape Memory Alloys) which have an
emerging and evaluating applications in many fields
such as Actuators, Couplings, Bio-medicals, Toys
and novelties, Heat engines, Sensors, Lifting devices
etc,.
This data is extracted from a few journals
and text books after the complete study of nitinol
practically and experimentally under the guidance
of a PhD., scholar. which are mentioned in the
below references reveals the idealistic properties of
the shape memory alloys.
nitinol wire comes back to its straightened shape
even if it is twisted into turns, when heat is applied
from a lighter to the wire. This automatic shape
transformation heat is applied is the unique property
of nitinol.
Even though the potential applications of nitinol
were identified at that time, the practical
implementation
of
these
applications
in
commercialization of nitinol took upto 1990‟s as
there were many practical obstacles regarding the
identification, manufacturing, related machinery and
creating awareness on that rare alloy combination.
However all these challenges were overcame by
early 1990‟s.
Initially this shape memory effect was discovered
early in the year 1932 by a Swedish scientist named
Arne olander observed this effect in the alloy of
gold and cadmium later in 1950‟s it was also
observed in copper and zinc alloy.
1. INTRODUCTION:
The entire description of the project can be
given as, conversion of the nitinol properties in to
mechanical energy without any external power
supply in maximum cases. Hence we can create a
renewable form of mechanical energy using these
simpler equipments.
The development of the project follows
with the study of the following contents:
2. MECHANISM:
1.1 THE HISTORY OF NITINOL:
T
he term Nitinol is the one derived from the
metallic composition that it exhibits and also
the place where exactly it is discovered.(Ninickel, Ti-Titanium, N-Naval, O-Ordnance, LLaboratory. (nickel, titanium, Naval Ordnance
Laboratory). Fortunately, William J.Buehler and
Frederick Wang, were the scientists who revealed
the properties of Nitinol in 1959. It was then when
buehler was in trials to discover a newer element
that could resist heat and some other impact forces,
he discovered that the combination of nickel and
titanium elements can give the expected solution.
The equal proportionate of these two elements
nickel and titanium forms into NITINOL. After
discovering the nitinol in 1959, he carried out many
experiments on its properties and exhibited a
presentation at a summit of laboratory management.
In that he demonstrated the shape memorizing effect
of the nitinol. It was shown that a straight ended
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Figure 1-The 3D view of structures of Ni-Ti
compound, Austenite and Martensite.
This reformable solid state phase transformation
which is also known as martensitic transformation is
an unusual property of the Nitinol, between two
different martensite crystal phases that require a
mechanical stress of 10,000–20,000psi (69138 mpa).
At high temperatures, nitinol acts as an
interpenetrating primitive cubic crystal structure
which is referred as austenite and also called as the
parent phase. Now At low temperatures, the nitinol
element transforms to the most complicated mono
clinical crystal structure known as martensite
spontaneously which is also called as sub-parental
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International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
phase (daughter phase). Generally, the temperature
where the transformation occurs from the austenite
stage to the martensite stage that particular
temperature is called as transformation temperature.
Further precisely, we can classify four transition
temperatures Ms, Mf, As, and Af. When the nitinol is
subjected to the cooled state austenite converts into
martensitic stage and thus we can name it is as
martensite start or Ms Temperature and the
temperature at which the complete martensitic stage
is formed is called as the martensite finish, or Mf
temperature. Now austenite starts to form when the
fully martensite is subjected to the heat and this
temperature is known as As temperature, and which
will be finished at the Af temperature.
method of deformation can be called as twinning
and hence this is also named as monoclinic
structure. The original austenite structure can be
regained from the martensite structure when heated
whether the martensite is deformed or not. Hence
this effect of memorizing the shape of austenite
stage even if the alloy is twisted into different
shapes is known as “shape memory effect” where
the alloy memorizes the austenite stage even after
subjected to many physical changes at low
temperature.
Figure 3-The behavior of nitinol's crystalline
structure at different temperatures.
The other outmost quality of the nitinol is that it is
an intermetallic compound where the atoms in it
have very specific lattice locations. Due to this it
becomes more hard to change from austenite to the
martensite stage which requires more force for the
deformation. The prevention of converting the
deformed martensite stage to the austenite stage
produces an effective force of 34000psi to
100000psi in the maximum number of cases.
Figure 2-Nitinol's phase transformation
indicating thermal hysteresis.
The cycle of heating/cooling shows the thermal
hysteresis. In general the nitinol composition and
the processing show their effect on the hysteresis
width. Its common value of temperature ranges are
21-51k; 21-51 °c; 37-91 °f.
Related to the phase transformation of nitinol their
exists two important points. The first point is that
the transformation is reversible which means the
crystallined structure is reverted to the original
austenite stage when heated above the
transformation
temperature.
Secondly
the
transformation can be done instantaneously in both
the directions.
The Martensite's crystal structure exhibits a peculiar
property at the time of its deformation. It deforms its
crystal structure in such a manner that their would
not be any breakage in its atomic bonding. This is
helps in re arranging the atomic planes without any
damage in maximum cases. If at all their exists any
damage, it ranges only from 6-8% of the total. This
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2.1 Thermal shape memory effect:
The alloy must be fixed in a particular desired
position and subjected to heat ranging at nearly
500 °c or 932 °f in order to fix its memorizable
shape. After affixing the alloy we can observe it
trying to go back to its original shape. This is due to
the super elastic property that it exhibits. The
general elasticity of the nitinol is 15 -30 times
greater than a normal spring.
A small change in the composition of nickel in
nitinol may bring the significant changes in the
transition temperature of the alloy. Generally nitinol
comprises of 50-51% of nickel in it atomically. So
we can vary the percentage of nickel inorder to vary
the Af temperature in nitinol to some extent, but
the super elastic temperature usually ranges from 25°c to +60°c.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
3. THE MANUFACTURING PROCESS:
The fabrication of nitinol has become more difficult
due to the tightly proportionate and accurate
composition of nickel and titanium. At present two
basic melting techniques are being implemented to
fabricate the NiTi alloy.
3.1 Vacuum Induction Melting: This method
follows the heating up of raw materials in the
alternating magnetic fields in the presence of carbon
or any other crucible
3.2 Vacuum Arc Remelting: In this method the raw
material along with a water cooled copper strike
plate are subjected to an electrical arc. This molten
form of liquid is melted and molded in a high
vacuum thus not introducing any carbon during its
melting.
Either of the methods are advantageous, there is no
particular differential analysis in between these two
techniques. The other methods used are physical
vapor deposition, plasma arc melting, e-beam
melting and induction skull melting.
There are a few considerations to be noticed while
fabricating the nitinol like heat treatment,
temperature and aging time considerations and
certain other parameters to maintain the properties
of a genuine nitinol. We can say that the heat
treatment of nitinol is a challenging task which is so
delicate. The removal of heat becomes difficult as
nitinol exhibits less thermal conductivity.
For that matter the hot working of nitinol is easy
when compared to the cold working as the super
elastic nature of the nitinol gives the better frictional
resistance. Grinding, laser cutting and electrical
discharge cuttings are comparatively easier
methods. However both the hot and cold treatments
are highly essential for a nitinol to maintain its
standard properties.
4. APPLICATIONS:
4.1 GENERAL APPLICATIONS:
Generally there are four common fields that uses the
applications of nitinol.
4.1.1 Free shape Recovery: A Nitinol material
which is deformed to any irregular shape prior to its
original shape can be rearranged or reformed back
to its original shape by subjecting the material to
any heat source.
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4.1.2 Pressurized Recovery: This can be obtained
when the normal shape recovery of the nitinol is
firmly subjected to some opposition. It recovers its
shape by creating some solid pressure or stress.
4.1.3 Mechanical energy Production: This is the
procedure where the shape recovery is allowed with
a little or capable oppose. Thus the recovering
process of the nitinol shows its impact on the
opposing substances.
4.1.4 Super elasticity: This is the major beneficiary
tool of the nitinol with extraordinary elastic
properties such as a super spring.
In the year 1989 there was a survey held at United
States and Canada with the involvement of seven
organizations. The idea of the survey was to predict
the future scope in the technology, applications and
market of SMA‟s. Finally the indulged companies
have given the following areas where the nitinol
usage can be implemented effectively:
1.
LIFTING DEVICES
2.
CRYOGENICALLY ACTIVATED DIE AND
BUBBLE MEMORY SOCKETS
C OUPLINGS
3.
SENSORS
4.
HEAT ENGINES
5.
ACTUATORS
6.
T OYS, DEMONSTRATION AND NOVELTY ITEMS
7.
B IOMEDICAL AND MEDICAL AND
8.
COUPLINGS
Nitinol can also be utilized mechanically in
some watch springs and resilient glass frames.
Biomedical and medical applications:
The Biocompatibility is also an unique feature of the
Nitinol and hence this is also used in orthopedic
implants. Due to certain other unique properties of
the nitinol it posses a massive usage in the
production of invasive devices. These invasive
devices also include super elastic needles, catheters
and stents.
Nitinol wires are used in identifying the breast
tumors very precisely. So that the related surgeries
can be carried out more precisely.
Actuators:
A nitinol wire can be used as an actuator efficiently
as we have already seen in the above example. This
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International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
can be mechanically actuated at the time of
necessity.
The above application shows the nitinol added to
schraeder valve core with the addition of an actuator
wire. The valve can very gradually close or open to
produce a proportionate controlled air flow through
the valve. Even this nitinol can be implemented in
operating the electrical latch box as electronic locks.
The nitinol wire contracts when heated electrically
and frees the latch. Of course this is a one of the low
cost implementing examples of many. There are
even more possibilities that can be achieved using
this nitinol as we know there are no limitations for
innovative applications.
Cryogenically activated die and bubble memory
sockets couplings:
The word „cryogenically‟ means the physical effects
occurring at very low temperatures. Using the shape
memory effect of the nitinol wire we can use this as
sockets couplings which can be activated by heating
the nitinol.
Sensors:
A Sensor is a device which transfers one form of
data or energy into another form. The electrical and
thermal properties of nitinol are so high these can be
effectively used as a sensor which indicates the
existence of thermal and electrical pulses through
the material. A nitinol wire can also perform
mechanical changes transforming from austenite to
martensite stages. Nitinol is used as a temperature
control system. It is possible to activate a variable
resistor or a switch to control the temperature using
its shape changing technique.
Figure 4 :Lifting with nitinol wire
The power supply connected to the nitinol wire can
be used to operate it in lifting and releasing the
certain weighted pendulum in the upward and
downward directions by switching on and off
respectively thus lifting the any other materials too.
A wire with the diameter of 250 micro meters and
length of one meter can pull a weight of 900 grams
approximately. It can deform its shape by 3% to 5%
of its original linear shape. Its activation
temperature is nearly 90 degrees centigrade and the
recommended current through the wire is 1050 mA.
5.2 As Heat engines:
Due to its high flexible and mechanical memory
properties it offers its service as a retractable
antenna or even as the boom of a microphone in
cellular technology.
5.
PROPOSED,
CONDUCTED
OBSERVED APPLICATIONS:
AND
5.1 As Lifting devices:
As we know the unique property of nitinol, which
can expand its length when electrically conducted,
we can make use of this function in lifting and
releasing the devices and materials.
Figure 5: Nitinol Heat engine
These heat engines make use of nitinol wire to
create mechanical energy from the two
neighbouring hot and cold compartments. The
prototype of the first heat engine was developed in
1970‟s by Ridgway Banks at Lawrence Berkley
National Laboratory and after his name that was
named as the Bank‟s engine. However the above
shown figure is the heat engine of latest version.
We can demonstrate this functionality in the
following diagram:
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International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
silent, variable movement cycle and can give us a
realistic motion.
5.3 In Toys, Demonstrations and Novelty items:
It is used in certain novelty products by the
magicians to perform some „psychic‟ powers as a
practical trick, such as automatically bending spoons
when stirred in a hot cup of tea or coffee or any
other hot liquid.
Hardware description:
In the following shown figure the nitinol wire is
implemented in a robotic arm. The nitinol wire is
placed in between the robotic fingers vertically and
pasted at both the ends with glue. These two ends
are connected to a power supply. Likewise all the
five fingers are connected with the five different
nitinol wires. We have constructed the below shown
circuit board using two IC‟s-the 4022 counter and
the 555 timer. We used the 555 timer as a bistable
vibrator. Based on the timer period set by the values
of capacitor C3 and the resistors R9 and R10, the
555 timer sends a pulse to pin 3.i.e., the output is
connected to ground. This is known as „Logic Low‟.
In this case we chose these values to give us a pulse
approximately every second.
Figure 8: Nitinol wire usage in Toys.
Here we have designed a bipedal robot and a horse
which can move forward based on the contraction
and relaxation movements of the nitinol wire when
electrically conducted. This movement can be varied
in terms of number of cycles per second using the
capacitor used in a simple oscillator circuit which
we used.It is also used in the golf club inserts as it
has the property of changing its shape. Nickel
titanium is also used in the field of textile industry
for building strong arm suits and other costume
material.
CONCLUSION:
It is highly essential to continue the study of the
characteristic features of SMA‟s for a large extent to
extract the much more possible outcomes in
generating mechanical and further forms of energy
with less equipment.
REFERENCES:
1)
Figure 7: Nitinol Robotic arm.
Another IC we used is the 4022 as a counter circuit.
It has an input pin and each time the voltage on this
pin is connected to ground for a brief fraction of a
second, it adds one to whatever number it already
had. It shows its current value by setting one of its
output pins to logic low, and the others are held at
logic high. After reaching the highest number that it
can hold, it rests to zero and continues counting.
In the same way, we can construct some other toys
as shown in the below figure which are purely
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Shape Memory Alloys: Manufacture, Properties and
Applications by H.R.Chen,ed.,Nova Science Publishers.
2) Shape Memory Materials and Its Applications by Y.Y. Chu
& L.C. Zhao, eds., Trans Tech Publications Ltd.,
3) Shape Memory Alloys by D.C. Lagoudas, ed.,Springer
Science and Business Media LLC.
4) Shape Memory Materials, K. Otsuka & C.M. Wayman,
eds.,Cambridge University Press.
5) Low Temperature Creep of Hot-extruded Nearstoichiometric NiTi Shape Memory Alloy, Sai V. Raj,
National Aeronautics and Space Administration, Glenn
Research Center.
6) "Effects of Low-Temperature Phase Changes on the
7) Mechanical Properties of Alloys Near Composition TiNi".
By Buehler, W. J. Gilfrich, J. W. Wiley, R. C.
(1963).Journal of Applied Physics.
8) "The Alloy That Remembers", Time, 1968-09-13
9) "Magnificent Molecules - Nitinol". The Mole (RSC) by
Withers, N. (2014).
10) "Nitinol facts". In (Nitinol.com. 2013).
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International Journal of Engineering Trends and Technology (IJETT) – Volume 29 Number 1 - November 2015
11) Shape memory alloys, by Funakubo, Hiroyasu (1984),
University of Tokyo.
12) Pelton, A. Russell, S. DiCello, J.(2003). "The Physical
Metallurgy of Nitinol for Medical Applications".
13) Miller, R. K. Walker, T.(1989). Survey on Shape Memory
Alloys. Survey Reports 89. Future Technology Surveys.
14) Banks.R.(1975)."TheBanksEngine". ieNaturwissenschaften.
15) Vimeo posting of "The Individualist", documentary on
Ridgway Banks
16) "Single wire nitinol engine" by Ridgway M. Banks, US
Patent.
17) "Metals that Remember", Popular Science, January 1988.
18) "Engine Uses No Fuel", Milwaukee Journal, December 5,
1973
AUTHORS DESCRIPTION
1. S.Swaroop kumar is pursuing
his M.Tech in the stream of Micro
&
Nano
electronics
from
Madanapalle
Institute
of
Technology
and
Sciences,
Madanapalle. He completed his
B.Tech in the stream of
Electronics and communication, from Hasvitha
institute of Engineering and technology, Hyderabad.
His areas of interest are embedded systems, IC
fabrication, and Micro & Nano electronics
2. Dr. S A K Jilani is working as the
Professor and project coordinator in
the department of ECE, Madanapalle
Institute
of
Technology
and
Sciences, Madanapalle. He has the
teaching experience of over twelve
years. He also worked as an R&D
Professional earlier in Electronics Industry. He
obtained his PhD In the year 2002 and also
published more than 35 papers in different national
and international Journals. He has also guided more
than 50 M.Tech, M.Sc, MCA, B.Tech Projects. His
areas of interest are Artificial Intelligence,
Computer Visions, Digital Signal Processing and
Embedded Systems.
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