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Submitted in fulfillment of the partialRequirement for the degree of Bachelor of
Engineering (Mechanical Engineering )
PERFORMANCE & QUALITY ASSESSMENT OF TWO RESIN
TRANSFER MOULDING (RTM) SYSTEMS(VARTM & HAND LAY UP)
Project Supervisor
Engr. Abdul Ghani Memon
BY
MOHAMMAD BASIT CHANDIO09ME47
(GROUP LEADER)
FARMAN ALI CHANNA09ME23
(ASSTT. GROUP LEADER)
MAHESH KUMAR 09ME19
MIR BILAWAL MIRJAT
09ME68
MUHAMMAD AMEEN SIYAL09ME06
DEPARTMENT OF MECHANICAL ENGINEERING
QUAID-E-AWAM UNIVERSITY OF ENGINEERING,
SCIENCE & TECHNOLOGY, NAWABSHAH.
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CERTIFICATE
This to certify that Mr._________________________________________
S/o________________________Roll No.______________ Final Year student of
Bachelor of Engineering (Mechanical Engineering) has completed the
compulsory requirement of Project / Thesis during the session, 2012-2013. This
thesis titled as PERFORMANCE & QUALITY ASSESSMENT OF TWO RESIN
TRANSFER MOULDING (RTM) SYSTEMS (VARTM & HAND LAY UP) is
submitted to the Quaid-e-Awam University of Engineering, Science and
Technology Nawabshah for the Award of Degree of Bachelor of Engineering
(Mechanical Engineering).
Engr. Abdul Ghani Memon External Examiner
Supervisor(Department of Mechanical Engineering)
QUEST Nawabshah. .
Prof. Dr. Altaf Hussain RajparChairman
(Department of Mechanical Engineering)
QUEST Nawabshah
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DEDICATION
I am dedicating my whole efforts to my Respected
PARENTS
Whom I am really inspired, their pure love, Devotion,
Natural attitude and sincerity is matter of great
Pleasure and pride for me
Their encouraging and simulating morally, socially and
Academically based teachings have always been
Proved for me as a
PATH TOWARD SUCCESS
They have give me name, which caused my
Identification in Society.
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ACKNOWLEDGEMENT
By the Grace of Omnipotent ALLAH Who gave us the strength, courage and
determination to complete this thesis, without His blessing the dream of
completing the thesis would never come true.
No list of acknowledgement would be completed without authors parents for their
sacrifice and encouragements. The author also would like to record his heartiest
gratitude to his beloved father and all family members, for their moral support
and inspiration throughout the study period.
Besides, Interesting to accomplish this thesis is also laborious job could not
carried without co-operation of concerned person. In this connection first of all we
are grateful to our dignified, whole hearted, polite and friendly attitude of our
supervisor Engr. Abdul Ghani Memon (Assistant Professor of Mechanical
Engineering Department of QUEST Nawabshah) for his full-fledged support.
Special thanks to Engr. Mushtaque Ahmed Lakho who helped us a lot to
complete this project.
With great respect and thanks, we express our gratitude to our Chairman
Prof. Dr. Altaf Hussain Rajpar, for given us the opportunity to work in this field.
GROUP LEADER&
MEMBERS
ABSTRACT
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The composite materials world is continuously enhancing by the introduction of new
materials with dependable characteristics required for latest developments in the
engineering applications. The latest development in textile composite formation due totheir light weight, high heat resistance and least cost of production
Air and water medium using systems, sport cars (formula cars), wind energy
have need of such type of properties possessing materials. There are further potential
applications e.g. defense, land transportation, construction, power generation sectors, rail,
automobile machine construct
In the present study a textile composite will be developed by using two
methodologies prepared for manufacturing composite under consideration is
1. VACUUM ASSISTED RESIN TRANSFER MOULDING PROCESS
(VARTM)
2. HAND LAYUP MOLDING METHOD
Work will be limited to study 2 & 4layers lamination with different orientations, 0/90, &
+45/-45, all other parameters will be keptsame.
CONTENTS
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___________________________________________________________________
CHAPTER NO. 01 INTRODUCTION
1.1 Introduction 01
1.1.1 Objectives 01
1.1.2 Plan of Work 01
1.2 Classification of Engineering Materials 02
1.2.1 Metals 02
1.2.2 Ceramics 02
1.2.3 Composites 02
1.2.4 Plastics 03
1.2.4.1 Thermoplastic 04
1.2.4.2 Thermosetting 04
1.3 Vinyal Easter 05
1.4 Glass Fabric 05
1.4.1 Uses of Glass Fabric 05
1.4.2 Glass-reinforced Plastic 06
1.5 Resin Transfer Molding (RTM 06
1.5.1 Process/ Methods of Resin Transfer Molding (RTM) 07
1.5.1.1 Vacuum Assisted Resin Injection (VARI) 07
1.5.1.2 Structural Reaction Injection Moulding 07
1.5.1.3 Resin Film Infusion (RFI) 07
1.5.1.3 Hand Layup RTM 08
1.5.1.4 Vacuum Assisted Resin Transfer Molding (VARTM) 09
1.5.2 Advantages of the Resin Transfer Molding Process 10
1.5.3 Limitations of the Resin Transfer Molding Process 11
1.5.4 Application of RTM 12
_____________________________________________________________________
CHAPTER NO. 02 LITERATURE REVIEW
2.1 Literature Review 13
_____________________________________________________________________
CHAPTER NO. 03 FABRICATION OF MOULD
3.1 Introduction 25
3.2 History 25
3.3 Process of Mould 25
3.4 Types of Mould 26
3.4.1 Expendable Mould or One Use Mould 26
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3.4.2 Nonexpendable Mould or Permanent Mould 26
3.5 Fabrication of Mould 26
3.5.1 Cutting of Acrylic Sheet for Mould 26
3.5.2 Fabrication of Vises for Holding and Tightening the Transparent Sheets 27
____________________________________________________________________
CHAPTER NO. 04 SAMPLE DEVELOPMENT
4.1 Ratio 32
4.2 Representation for Sample Development 32
4.3 Mould A 35
4.4 Mould B 35
4.5 Mould C 36
4.6 Mould D 36
4.7 Mould E 37
4.8 Mould F 37
4.9 Mould G 38
_____________________________________________________________________
CHAPTER NO. 05 TESTING AND RESULT DISCUSSION
5.1 SSTM-20 KN TESTING MACHINE 40
5.2 TEST SPECIMEN OF COMPOSITE MATERIAL A. 41
5.2.1 Test Specimen of Composite Material A1 41
5.2.2 Test Specimen of Composite Material A2 43
5.3 Test Specimen of Composite Material B 45
5.3.1 Test Specimen of Composite Mateiral B1 45
5.3.2 Test Specimen of Composite Material B2 47
5.4 Test Specimen of Composite Material C 49
5.4.1 Test Specimen of Composite Material C1 49
5.4.2 Test Specimen of Composite Material C2 51
5.5 Test Specimen of Composite Material D 53
5.5.1 Test Specimen of Composite Material D1 53
5.5.2 Test Specimen of Composite Material D2 55
5.6 Test Specimen of Composite Material E 57
5.6.1 Test Specimen of Composite Material E1 57
5.6.2 Test Specimen of Composite Material E2 59
5.7 Test Specimen of Composite Material F 61
5.7.1 Test Specimen of Composite Material F1 61
5.7.2 Test Specimen of Composite Material F2 63
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5.8 Test Specimen of Composite Material G 65
5.8.1 Test Specimen of Composite Material G1 65
5.8.2 Test Specimen of Composite Material G2 67
5.9 test Specimen of Simple Fabric Glass (F.G) 69
5.10 Results 71
_____________________________________________________________________
CHAPTER NO. 06 CONCLUSION
6.1 Conclusion 72
6.2 Future Work (Suggestions) 73
References 74
CHAPTER NO. 1
INTRODUCTION
1.1 ENGINEERING MATERIALS
Since the earliest days of the evolution of mankind , the main distinguish between
human begins and other creatures has been the ability to use and develop materials
to satisfy our requirements. Nowadays we use various materials to satisfy ourrequirements for housing, heating, furniture, clothes, transportation, entertainment,
medical care, defense and all the other trappings of a modern, civilized society.
1.1.1 Objectives
i. Development of samples by using:
Vacuum assisted resin transfer molding
Hand layup molding
ii. Testing of developed samples (Tensile behavior)
iii. Analyzing of results
1.1.2 Plan of work
i. Mould forming
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ii. Sample development
iii. Testing
iv. Result discussion
1.2 CLASSIFICATION OF ENGINEERING MATERIALS
Engineering Materials are generally classified into following families
1.2.1 Metals
Metals are elements, compounds or alloys that area good conductors of both electricity
and heat. Metals also have properties such as luster or shine of their surface (when
polished), their malleability (ability to be hammered) andductility (ability to be drawn).
1.2.2 Ceramics
Ceramics are compounds between metallic and nonmetallic elements; they are most
frequently oxides, nitrides, and carbides. For example, some of the common ceramic
materials include aluminum oxide (or alumina, Al2O3), silicon dioxide (or silica, SiO2),
silicon carbide (SiC), silicon nitride (Si3N 4), and, in addition, what some refer to as the
traditional ceramics those composed of clay minerals (i.e., porcelain), as well as cement,
and glass.
1.2.3 Composites
As was mentioned that alloys of metals with non-metals could only occur if all the
component materials were miscible, that is, soluble in each other in the molten state.
Composite materials can be made up from materials that are not soluble in each other.
Composite materials are not alloys.
In its simplest form a composite material consists of two dissimilar materials in which
one material forms a matrix to bond together the other (reinforcement ) material. The
matrix and reinforcement are chosen so that their mechanical properties complement each
other, whilst their deficiencies are neutralized. For example, in GRP molding, the
polyester resin is the matrix that binds together the glass fiber reinforcement.
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Material property combinations and ranges have been extended by the development of
composite materials. Generally speaking, a composite is considered to be any multiphase
material that exhibits a significant proportion of the properties of both constituent phases
such that a better combination of properties is realized. According to this principle of
combined action, better property combinations are fashioned by the judicious
combination of two or more distinct materials. Property trade-offs are also made for
many composites.
In designing composite materials, scientists and engineers have ingeniously combined
various metals, ceramics, and polymers to produce a new generation of extraordinary
materials. Most composites have been created to improve combinations of mechanical
characteristics such as stiffness, toughness, and ambient and high-temperature strength.
In a composite, the reinforcement material, in the form of rods, strands, fibers or
particles, is bonded together with the other matrix materials. For example, the fibers may
have some of the highest moduli and greatest strengths available in tens ion, but little
resistance to bending and compressive forces. On the other hand, the matrix can be
chosen to have high resistance to bending and compressive forces. Used together these
two different types of material produce a composite with high tensile and compressive
strengths and a high resistance to bending.
1.2.4 Plastics
Plastics are materials that have some structural rigidity under load, and are used in
general-purpose applications. Polyethylene, polypropylene, poly(vinyl chloride),
polystyrene, and the fluorocarbons, epoxies, phenolics, polyesters and vinyleaster
may all be classified as plastics. They have a wide variety of combinations of
properties.
Some plastics are very rigid and brittle. Others are flexible, exhibiting both elastic and
plastic deformations when stressed, and sometimes experiencing considerable
deformation before fracture.
Based on their response to temperature, plastic materials may be classified into two main
categories:
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1.2.4.1 Thermoplastic
By far the most common in the school workshop. These plastics do not resist heat very
well and so can be easily formed into other shapes. On heating this type of plastic does
not undergo a chemical change (as is the case with thermosetting plastic) and waste can
be re-ground into granules and re-used. A heated sheet of thermoplastic which has been
molded into a shape can be reheated and it will go back to its original shape. This
returning to shape is referred to as plastic memory.
Sometimes, thermoplastics are confused with thermosetting plastics. Although they may
sound the same, they actually possess very different properties. While thermoplastics can
be melted to a liquid and cooled to a solid, thermosetting plastics chemically deteriorate
when subjected to heat. Ironically, however, thermosetting plastics tend to be more
durable when allowed to cool than many thermoplastics.
Polyethylene, polypropylene and PVC (polyvinyl chloride) are the most common
examples of thermoplastic.
1.2.4.2 Thermosetting
Thermoset materials are usually liquid ormalleable prior to curing and designed to
be molded into their final form, or used as adhesives. Others are solids like that of the
molding compound used in semiconductors and integrated circuits (IC). Once hardened a
thermoset resin cannot be reheated and melted back to a liquid form.
A thermosetting polymer is a prepolymer in a soft solid or viscous state that changes
irreversibly into an infusible, insoluble polymer network by curing. Curing can be
induced by the action of heat or suitable radiation, or both. A cured thermosetting
polymer is called a thermoset, these are stronger and harder than thermoplastics. They
resist heat and fire and are often used for objects like pan handles and electrical fittings.
The most common thermosetting resin used today is polyester resin, followed by
vinylester and epoxy. Thermosetting resins are popular because uncured, at room
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temperature, they are in a liquid state. This allows for convenient impregnation of
reinforcing fibers such as fiberglass, carbon fiber, or Kevlar. [6]
1.3 VINYL EASTER
Vinyl ester resins are stronger than polyester resins and cheaper than epoxy resins. Vinyl
ester resins utilize a polyester resin type of cross-linking molecules in the bonding
process. Vinyl ester is a hybrid form of polyester resin which has been toughened with
epoxy molecules within the main molecular structure. Vinyl ester resins offer better
resistance to moisture absorption than polyester resins but it's downside is in the use of
liquid styrene to thin it out (not good to breath that stuff) and its sensitivity to
atmospheric moisture and temperature. Sometimes it won't cure if the atmospheric
conditions are not right. It also has difficulty in bonding dissimilar and already-cured
materials. It is not unusual for repair patches on vinylester resin canoes to delaminate or
peel off. As vinylester resin ages, it becomes a different resin (due to its continual
curing as it ages) so new vinylester resin sometimes resists bonding to your older canoe,
or will bond and then later peel off at a bad time. It is also known that vinylester resins
bond very well to fiberglass, but offer a poor bond to kevlar and carbon fibers due to the
nature of those two more exotic fibers. Due to the touchy nature of vinylester resin,
careful surface preparation is necessary if reasonable adhesion is desired for any repair
work.
1.4 GLASS FABRIC
Glass fiber is a material consisting of numerous extremely fine fibers of glass. Glass
fabric contains large numbers of glass fiber. Glass fiber is commonly used as an
insulating material. It is also used as a reinforcing agent for many polymer products; to
form a very strong and light fiber-reinforced polymer (FRP) composite material called
glass-reinforced plastic (GRP), popularly known as "fiberglass". Glass fiber has roughly
comparable properties to other fibers such as polymers and carbon fiber. Although not as
strong or as rigid as carbon fiber, it is much cheaper and significantly less brittle. [2]
1.4.1 Uses of Glass Fabric
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Glass fiber is commonly used as an insulating material. It is also used as a reinforcing
agent for many polymer products; to form a very strong and light fiber-reinforced
polymer (FRP) composite material called glass-reinforced plastic (GRP), popularly
known as "fiberglass". Glass fiber has roughly comparable properties to other fibers such
as polymers and carbon fiber. Although not as strong or as rigid as carbon fiber, it is
much cheaper and significantly less brittle. [3] [4]
1.4.2 Glass-reinforced Plastic
Glass-reinforced plastic (GRP) is a composite material or fiber-reinforced plastic made of
a plastic reinforced by fine glass fibers. Like graphite-reinforced plastic, the composite
material is commonly referred to as fiberglass. The glass can be in the form of a chopped
strand mat (CSM) or a woven fabric. [3] [4]
As with many other composite materials (such as reinforced concrete), the two materials
act together, each overcoming the deficits of the other. Whereas the plastic resins are
strong in compressive loading and relatively weak in tensile strength, the glass fibers are
very strong in tension but tend not to resist compression. By combining the two
materials, GRP becomes a material that resists both compressive and tensile forces well.
[5]
The two materials may be used uniformly or the glass may be specifically placed in those
portions of the structure that will experience tensile loads. [3] [4]
1.5 RESIN TRANSFER MOLDING (RTM)
The Resin Transfer Molding (RTM) process is a cost-effective fabrication method for the
manufacture of polymer composites. In a traditional RTM process, catalyzed
thermosetting resin is injected into an enclosed metal mold containing a previously
positioned reinforcement preform. The preform is compacted to the specified fiber
volume fraction when the matched metal mold is closed. The resin wets out the fiber until
the mold is filled, and the part is then cured inside the mold. A schematic diagram of the
process is shown in following Figure 1.1.
RTM offers several advantages over other composite fabrication methods such as auto-
clave and compression molding of prepreg tape laminates. First, high fiber volume
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fraction composites can be fabricated with low void contents. Second, parts with highly
complex shapes can be molded by incorporating many components into a single preform.
This helps to reduce the cost and weight of the structure. Third, hand lay-up of prepreg
tape is eliminated. Production rates are increased and operating costs are reduced.
Finally, RTM is a closed mold process that reduces the workers exposure to harmful
volatiles, i.e., styrene, associated with many of the room temperature processing resins.
However, the matched metal tooling used in the RTM procedure is expensive, and the
tooling design becomes difficult when fabricating large and complex shaped parts. [7]
Figure 1.1 Resin Transfer molding (RTM)
1.5.1 Processes/Methods of Resin Transfer Molding (RTM)
There are so many methods of resin transfer molding, which includes:
1.5.1.1 Vacuum Assisted Resin Injection (VARI)
We have moulds that are usually vented. A partial vacuum holds the mould in place and
provide the moulding force, the vacuum also aids reduction of voids in laminates of large
area.
1.5.1.2 Structural Reaction Injection Moulding
In this type of moulding, we have a high pressure rapid dispensing process typically for
polythene which has low viscosity.
1.5.1.3 Resin Film Infusion (RFI)
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In this process of moulding, we have a single mould and vacuum bag. The resin
introduced as pellets of a film along with the reinforcement. The mould in the vacuum
bag is heated under pressure to lower the viscosity of the resin which flows through the
thickness as opposed to along the part as with the other methods.
1.5.1.3 Hand Layup RTM
Hand lay-up is a simple method for composite production. A mold must be used for hand
lay-up parts unless the composite is to be joined directly to another structure. The mold
can be as simple as a flat sheet or have infinite curves and edges. For some shapes,
molds must be joined in sections so they can be taken apart for part removal after curing.
Before lay-up, the mold is prepared with a release agent to insure that the part will not
adhere to the mold. Reinforcement fibers can be cut and laid in the mold. It is up to the
designer to organize the type, amount and direction of the fibers being used. Resin must
then be catalyzed and added to the fibers. A brush, roller or squeegee can be used to
impregnate the fibers with the resin. The lay-up technician is responsible for controlling
the amount of resin and the quality of saturation. Following figure 1.2 shows the basic
process of hand lay-up. [8]
Figure 1.2 Hand Lay-up RTM
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1.5.1.4 Vacuum Assisted Resin Transfer Molding (VARTM)
Vacuum infusion is a process used for moulding fibre composite mouldings, where
uniformly distributed fibres are layered in one of the mould parts, said fibres being
rovings, i.e. bundles of fibre bands, bands of rovings or mats, which are either felt mats
made of single fibres or woven mats made of fibre rovings.
The second mould part, which is often made of a resilient vacuum bag, is subsequently
placed on top of the fibre material. By generating a vacuum, typically 80 to 90% of the
total vacuum, in the mould cavity between the inner side of the mould part and the
vacuum bag, the liquid polymer can be drawn in and fill the mould cavity with the fibre
material contained therein. So-called distribution layers and distribution tubes, also called
inlet channels, are used between the vacuum bag and the fibre material in order to obtainas sound and efficient a distribution of polymer as possible. In most cases the polymer
applied is polyester or epoxy, and the fibre reinforcement is most often based on glass
fibres or carbon fibres.
During the process of filling the mould, a vacuum is generated by the vacuum channels
in the mould cavity, said vacuum in this connection being understood as a negative
pressure, whereby liquid polymer is drawn into the mould cavity via the inlet channels in
order to fill said mould cavity as shown in following figure 1.3.
From the inlet channels the polymer disperses in the mould cavity as flow front moves
towards the vacuum channels. Thus it is important to position the inlet channels and the
vacuum channels optimally in order to obtain a complete filling of the mould cavity.
Ensuring a complete distribution of the polymer in the entire mould cavity is, however,
often difficult, and accordingly this often results in so-called dry spots, i.e. areas with
fibre material not being sufficiently impregnated with resin. Thus dry spots are areas,
where the fibre material has not been impregnated, and where there can be air pockets,
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which are difficult to remove by controlling the vacuum pressure and possibly an
overpressure at the inlet side.
In connection with vacuum infusion employing a solid mould part and a resilient mould
part in the form of a vacuum bag, the dry spots can be repaired after the process of filling
the mould by for example perforating the cloth in the respective locations and by sucking
out air by means of a syringe needle. Liquid polymer can optionally be injected at the
relevant location, which can for example be done by means of a syringe needle as well.
This is a time-consuming and tiresome process. In the case of large mouldings, the staff
has to stand on the vacuum bag, which is not desirable, especially not when the polymer
has not hardened, as it can result in deformations in the inserted fibre material and thus
result in local weakening of the structures. [9]
Fig
ure 1.3, Vacuum Assisted Resin Transfer Molding (VARTM)
1.5.2 Advantages of the Resin Transfer Molding Process
i. Initial investment cost is low because of reduced tooling costs and operating
expenses as compared to compression molding and injection molding. For this
reason, prototypes are easily made for market evaluation. For example, the dish
antenna was first made using an RTM process to validate the design features
before capital investment was made for compression molding of SMC parts.
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ii. Moldings can be manufactured close to dimensional tolerances.
iii. RTM processing can make complex parts at intermediate volume rates. This
feature allows limited production runs in a cost-effective manner. This lends
benefits to the automotive market, in which there is a growing need toward lower
production volumes per car model and quicker changes to appeal to more niche
markets.
iv. RTM provides for the manufacture of parts that have a good surface finish on
both sides. Sides can have similar or dissimilar surface finishes.
v. RTM allows for production of structural parts with selective reinforcement and
accurate fiber management.
vi. Higher fiber volume fractions, up to 65%, can be achieved.
vii. Inserts can be easily incorporated into moldings and thus allows good joining and
assembly features.
viii. A wide variety of reinforcement materials can be used.
ix. RTM offers low volatile emission during processing because of the closed
molding process.
x. RTM offers production of near-net-shape parts, hence low material wastage and
reduced machining cost.
xi. The process can be automated, resulting in higher production rates with less
scrap.
1.5.3 Limitations of the Resin Transfer Molding Process
Although RTM has many advantages compared to other fabrication processes, it also has
the following limitations.
i. The manufacture of complex parts requires a good amount of trial and error
experimentation or flow simulation modeling to make sure that porosity and dry
fiber free parts are manufactured.
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ii. Tooling and equipment costs for the RTM process are higher than for hand lay-up
and spray-up processes.
iii. The tooling design is complex.
1.5.4 Applications of RTM
There are widely so many applications of RTM in the world. Some applications are
carried out for manufacturing the following parts:
Auto body panels Truck air deflectors
Wind blades Chemical storage tanks
Solar collectors (40 ft diameter, 36 parts) RV components
Propellers Bathtub/shower units
Antenna dishes Chairs
Swim pool panels Helmets
Doors Hockey sticks
Bicycle frames Sports car bodies
Aircraft parts
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CHAPTER NO. 2
LITERATURE REVIEW
2.1 LITERATURE REVIEW
A composite is when two or more different materials are combined together to create a
superior and unique material. The first uses of composites date back to the 1500s .C.
when early Egyptians and Mesopotamian settlers used a mixture of mud and straw to
create strong and durable buildings. Straw continued to provide reinforcement to ancient
composite products including pottery and boats.
Later, in 1200 AD, the Mongols invented the first composite bow. Using a combination
of wood, bone, and animal glue, bows were pressed and wrapped with birch bark.
These bows were extremely powerful and extremely accurate. Composite Mongolian
bows provided Genghis Khan with military dominance, and because of the composite
technology, this weapon was the most powerful weapon on earth until the invention of
gunpowder.[10]
Birth of the Plastics Era
The modern era of composites did not begin until scientists developed plastics. Until
then, natural resins derived from plants and animals were the only source of glues and
binders. In the early 1900s, plastics such as vinyl, polystyrene, phenolic and polyester
were developed. These new synthetic materials outperformed resins that were derived
from nature.
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However, plastics alone could not provide enough strength for structural applications.
Reinforcement was needed to provide the strength, and rigidity. In 1935, Owens Corning
introduced the first glass fiber, fiberglass. Fiberglass, when combined with a plastic
polymer creates an incredibly strong structure that is also lightweight. This is the
beginning of the Fiber Reinforced Polymers (FRP) industry as we know it today.
Driving Early Composites Innovation
Many of the greatest advancements in composites were incubated by war. Just as the
Mongols developed the composite bow, World War II brought the FRP industry from the
laboratory into actual production.
Alternative materials were needed for lightweight applications in military aircraft.
Engineers soon realized other benefits of composites beyond being lightweight and
strong. It was discovered that fiberglass composites were transparent to radio frequencies,
and the material was soon adapted for use in sheltering electronic radar equipment
(Radomes).
Adapting Composites: Space Age to Everyday
By the end of the WWII, a small niche composites industry was in full swing. With lower
demand for military products, the few composites innovators were now ambitiously
trying to introduce composites into other markets. Boats were an obvious fit for
composites, and the first commercial boat hull was introduced in 1946.
At this time Brandt Goldsworthy, often referred to as the grandfather of composites,
developed new manufacturing processes and products. He is credited with numerous
advancements including being the first to fiberglass a surfboard, which revolutionized the
sport.
Goldsworthy also invented a manufacturing process known as pultrusion. Today,
products manufactured from this process include ladder rails, tool handles, pipes, arrow
shafts, armor, train floors, medical devices, and more.
Continued Advancement in Composites
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In the 1970s the composites industry began to mature. Better plastic resins and improved
reinforcing fibers were developed. DuPont developed an aramid fiber known as Kevlar,
this fiber has become the standard in armor due to its high tenacity. Carbon fiber was also
developed around this time; it has since been replacing metal as the new material of
choice.
The composites industry is still evolving, with much of the growth is now focused around
renewable energy. Wind turbine blades are constantly pushing the limits on size and are
requiring advanced materials, designs, and manufacturing.
Looking Forward
In the future, composites will utilize even better fibers and resins, many of which will
incorporate nano-materials. Dedicated university programs and research institutions will
continue to develop improved materials and ways to manufacture them into products.
Additionally, composites are on the path towards being more environmentally friendly.
Resins will incorporate recycled plastics and bio-based polymers. Composites will
continue to make the world lighter, stronger, more durable, and a better place to live. [11]
Recently research work, new innovations and modified techniques of RTM in textile
composite materials and future work suggested by researchers for obtaining best
results are described below:
In 1999, Jon Dana Skramstad worked on Evaluation Of Hand Lay-Up And Resin
Transfer Molding In Composite Wind Turbine Blade Manufacturing and he represented
that currently, the majority of the turbine blade industry uses the low budget, hand lay-up
manufacturing technique to process composite blades. The benefits of hand lay-up
include the ability to fabricate large, complex parts with a quick initial start-up. Yet, the
drawbacks of the hand lay-up technique suggest that other methods of composites
manufacturing may be more desirable in industrial-scale, wind turbine blade fabrication.
Resin transfer molding (RTM) was identified as a processing alternative and shows
promise in addressing the shortcomings of hand lay-up in turbine blade manufacturing.
The current study compares and evaluates both processes according to fundamental
criteria and mechanical performance for a variety of fabric reinforcements, lay-up
schedules and turbine blade critical structures. The geometries investigated were flat
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plates, thin flanged T-stiffeners with skin intersections, thick flanged T-stiffeners, I-beam
load carriers, and sample root connection joints. The variables that were explored and
compared according to process included laminate thickness, fiber volume, cycle time, and
porosity. Flat plates were tested under five typical loading conditions: transverse tension,
compression, three-point bending, axial tension, and fatigue. The variety of three-
dimensional substructures was also tested mechanically to determine what effects
processing might have on structural performance. In this study it was found that process
played an important role in laminate thickness, fiber volume, and weight for the
geometries investigated. RTM was found to reduce thicknesses and improve weights for
all substructures. In addition, RTM processing resulted in tighter material transition radii
and eliminated the need for most secondary bonding operations. These observations were
found to significantly reduce weight for complex structures. Hand lay-up was
consistently slower in fabrication times when compared to RTM for the manufacturing of
the specimens tested in this study. Computed Tomography (CT) technology was
introduced as a means to measure porosity for specimens of different processing.
However, the current efforts in characterizing porosity via CT suggest further refinement.
Analysis of the mechanical testing results for flat plate specimens demonstrated that
vacuum-assisted RTM specimens performed notably better than their hand lay-up
counterparts for a variety of properties. Yet, thickness played a critical role in comparing
the mechanical test results of flat plate specimens. Variations in thickness had the
tendency to bias the structural performance results according to process and as a result,
fiber volume normalizing techniques were introduced. Specimen normalization was
found to reduce the measurable differences between flat plate test results for specimens
manufactured by the different processes. It was also noted that in most cases
reinforcement played a more instrumental role in mechanical performance than process.
Substructure tests demonstrated that differences in processing methods affected specimen
mass and moment of inertia. These properties were greater for the hand lay-up specimens
and resulted in improvements in ultimate strength and initial damage when compared to
RTM substructures. The current root specimen design does not show significant
differences according to process and exceeds all static and fatigue requirements.
After achieving his results he suggested some future work is given in following steps:
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Further investigations into alternative warp, unidirectional fabrics may yield a
reinforcement that significantly outperforms the current A130 fabric for laminate
compressive and bending properties in turbine blade applications.
Comparisons in fatigue performance between hand lay-up and RTM flat plates should
be expanded with further variations in fiber volume, lay-up, and fabric type.
Minimizing the use of gaskets that also serve as spacing materials would be beneficial
to future resin transfer moldings. Combination gasket/spacers are poor in dimensional
repeatability, can undesirably effect fiber volume, and contribute to complications with
maintaining vacuum integrity. [12]
In year 1999, Mr. Tom J. Wu* & H. Thomas Hahn, Worked on The Bearing Strength of
E-Glass/Vinyl-Ester Composites Fabricated by VARTM and they investigated the
bearing properties of mechanically fastened glass-fiber/vinyl-ester composite joints. Two
glass composites of deferent fabrics and lay-ups were fabricated by vacuum-assisted
resin-transfer molding (VARTM) and tested by using a double-lap joint configuration.
The results of this study are presented as experimental characterization and analytical
prediction. The major focus of the experimental part of the paper was to characterize the
bearing failure behavior of these composites. The erects of geometric parameters were
evaluated and correlated with the resulting bearing strength and failure modes by the
statistical method of analysis of variance. From the experimental results obtained, it is
concluded that the edge-distance ratio (e/d) and thickness of the specimen strongly eject
the bearing strength of the composites. On the other hand, the failure mode is deter-
mined by the width ratio (w/d). In the analytical part of the study, Chang's strength-
prediction model, which is based on a two-dimensional finite-element analysis, was
utilized to predict the bearing strength of these composite joints. The predicted valueswere compared with the experimental data obtained from this study and the results
suggest that this model can be used to give accurate pre-dictions of the bearing strength
of these composites.
After this complete research and study they concluded that double-lap joint bearing tests
for E-glass/vinyl-ester epoxy composite (M3 and M4) were per-formed. The following
observations were made as a result of the experimental analysis.
(a) Ultimate bearing strength increases as thickness and ratio increases.
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(b) At similar/ratio and thickness, M3 specimens with 6.35mm hole have on the average
140MPahigher bearing strength than specimens with 12.7mm hole.
(c) When thickness
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incorporates resin flow through the preform, compaction and relaxation of the preform,
and viscosity and cure kinetics of the resin. The computer model can analyze the resin
flow details, track the thickness change of the preform, predict the total infiltration time
and final fiber volume fraction of the parts, and determine whether the resin could
completely infiltrate and uniformly wet out the preform. The modeling software was used
to examine how the distribution medium and the position of the resin inlet tube effect the
resin infiltration of a flat preform. Three different distribution medium and resin inlet
tube configurations were evaluated using the model and the results were compared with
data collected during resin infiltration of a carbon fabric preform. The results show how
the distribution medium influences the resin infiltration process and that resin infiltration
into the preform can be accurately predicted when the distribution medium is modeled
correctly. [14]
In 2003, C. Ulven, U.K. Vaidyaa and M.V. Hosur researched on Effect of Projectile
Shape During Ballistic Perforation of VARTM Carbon/Epoxy Composite Panels and the
use of carbon/epoxy composites in aircraft, marine, and automotive structural
applications is steadily increasing. Robust composite structures processed using low-cost
techniques with the purpose of sustaining high velocity impact loads from various threats
are of great interest. An example of a low-cost process is the out-of-autoclave, vacuum
assisted resin transfer molding (VARTM) technique. The present study evaluates the
perforation and damage evolution created by various projectile geometries in VARTM
processed carbon/epoxy laminates. A series of ballistic impact tests have been performed
on satin weave carbon/epoxy laminates of 3.2 and 6.5 mm thickness, with projectile
geometries representing hemispherical, conical, fragment simulating and flat tip. A gas-
gun with a sabot stripper mechanism was employed to impact the samples with 50-caliber
projectiles of the different shapes. The perforation mechanism, ballistic limit, and damageevolution of each laminate has been studied. The conical shaped projectile resulted in
highest ballistic limit, followed by the flat, hemispherical and the fragment simulating.
After working on their research they summarized their research as the influence of
projectile shape in the studied car-bon/epoxy laminates under high velocity impact
resulted in a range of energy absorptions at ballistic limit. Conical projectile high velocity
impact resulted in the greatest amount of energy absorbed at ballistic limit followed by
flat, hemispherical, and fragment simulating projectile impact. Failure mechanisms of
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plugging, separation of fibers, or a combination of both were observed in the
carbon/epoxy laminates during high velocity impact of different shaped projectiles. Panel
thickness has a significant effect on the ballistic limit of panels impacted by different
shaped projectiles. Thin carbon/epoxy panels bend easily during a ballistic event which
absorbs a majority of the projectiles energy regardless of shape. In thick carbon/epoxy
panels, projectile shape induces different failure mechanisms which result in different
ballistic limits. The trend of ballistic limits for the carbon/epoxy laminates impacted by
the different shaped projectiles was predicted using current analytical equations by Wen.
[15]
In 2003, Jeffrey A. Acheson, Pavel Simacek and Suresh G. Advani researched on The
implications of fiber compaction and saturation on fully coupled VARTM simulation
and they stated that Vacuum Assisted Resin Transfer Molding (VARTM) is a process by
which resin is drawn through fiber preforms in a one-sided mold using an induced
pressure gradient. Although the approach to model flow in VARTM is similar to the
Resin Transfer Molding (RTM) process, modeling in VARTM can be significantly more
complex if one accounts for fiber compaction and the dual scale nature of the fiber
preform which is present in RTM but often neglected. This article investigates the
influence of fiber compaction and fiber tow saturation during mold filling in the VARTM
process. A non-rigid control volume is used to formulate a set of governing equations to
describe the resin flow. Tow impregnation at the micro-scale is coupled with global resin
flow at the macro scale by applying conservation of mass principles. Preform compaction
is modeled as a non-linear spring bed where compaction pressure is dynamically
distributed between the resin and the preform. The variation in preform permeability is
modified due to the changes in the fiber volume fraction as a result of changing
compaction. A simple one-dimensional mold filling case is solved to investigate the roleof compaction and dual scale porous media in VARTM processes. A parametric study
allows us to identify situations in which one can neglect compaction and saturation and
conditions under which a fully coupled model should be applied for satisfactory results.
After their complete research they concluded their whole research as this article
investigated the common modeling assumptions that compaction effects and fiber tow
saturation has little influence on the VARTM process. A non-rigid control volume was
used to formulate a set of governing equations to describe the resin flow. Tow
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impregnation at the micro scale is coupled with global resin flow at the macro scale by
applying conservation of mass principles. Preform compaction is modeled as a non-linear
spring bed where compacting pressure is dynamically distributed between the resin and
the preform. The variation in preform permeability is modified according to the Kozeny
Carman equation due to the changes in the fiber volume fraction as a result of changing
compaction. The results show that the resin pressure curve can be significantly different
with and without compaction. This implies that pressure values derived from uncoupled
analytical techniques should expect inaccuracies depending on the varying levels of
compaction present in the experiment. The fill times for both the coupled and uncoupled
compaction cases can be made to match if an effective permeability is used for the
uncoupled case. Note, however, that this effective permeability will be different for the
same material being injected under different pressures and may not be accurate in filling
complex geometric parts. Because preforms compact non-linearly, most of the change in
compaction and hence the change in thickness occurs close to the injection port
especially for system where the change in compaction is high. The length of the partially
saturated region can be derived analytically. Furthermore, since the shape of the pressure
curve varies with time, a single effective permeability will not be able to perfectly fit the
curve. However, while the saturation effects on pressure and fill time are small even for
the worst cases, the effects on the quality of the final part due to fiber tow saturation can
be considerable[16].
They suggested that Future work on this topic should be done on compaction effects in
more complex filling geometries and determine whether the use of an effective fiber
permeability would still be acceptable in modeling and simulation of the VARTM
process similar to the RTM process[17-18-19]
In 2004, M. Grujicica, K.M. Chittajallu and Shawn Walsh worked on Non-isothermal
preform infiltration during the vacuum-assisted resin transfer molding (VARTM)
process and they developed a control-volume finite-element model to analyze the
infiltration of a fiber preform with resin under non-isothermal conditions within a high-
permeability resin-distribution medium based vacuum-assisted resin transfer molding
(VARTM) process. Due to the exposure to high temperatures during preform infiltration,
the resin first undergoes thermal-thinning which decreases its viscosity. Subsequently
however, the resin begins to gel and its viscosity increases as the degree of
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polymerization increases. Therefore, the analysis of preform infiltration with the resin
entails the simultaneous solution of a continuity equation, an energy conservation
equation and an evolution equation for the degree of polymerization. The model is
applied to simulate the infiltration of a rectangular carbon fiber based preform with the
NBV-800 epoxy resin and to optimize the VARTM process with respect to minimizing
the preform infiltration time. The results obtained suggest that by proper selection of the
ramp/hold thermal history of the tool plate, one can reduce the preform infiltration time
relative to the room-temperature infiltration time. This infiltration time reduction is the
result of the thermal-thinning induced decrease in viscosity of the ungelled resin.
On the basis of results obtained in their work they drawn following conclusions:
1. By adding to the incompressible-fluid mass conservation equation an energy
conservation equation and an equation for the time and temperature evolution of the
degree of polymerization of the resin, the control-volume finite-element method
originally proposed by Lee and co-workers [2021] has been extended to analyze
preform infiltration stage of a high-permeability medium based vacuum-assisted resin
transfer molding (VARTM) process.
2. Simulations of the preform infiltration process under non-isothermal conditions
showed that, at short infiltration times, the effect of tool-plate heating can be beneficial
and can lead to an increase in the rate of infiltration. This effect has been attributed to a
thermal-thinning based reduction in the resin viscosity. [22]
In 2010, B. J. Jensen, R. J. Cano, S. J. Hales ' , J. A. A lexa2, E. S. Weiser, A. C. Loos
and W. S. Johnson researched together on FIBER METAL LAMINATES MADE BY
THE VARTM PROCESS and presented that Fiber metal laminates (FMLs) are multi-
component materials utilizing metals, fibers and matrix resins. Tailoring their properties
is readily achievable by varying one or more of these components. Established FMLs like
GLARE utilize aluminum foils, glass fibers and epoxy matrices and are manufactured
using an autoclave. Two new processes for manufacturing FMLs using vacuum assisted
resin transfer molding (VARTM) have been developed at the NASA Langley Research
Center (LaRC). A description of these processes and the resulting FMLs are presented.
After completing their research they concluded that two types of fiber metal laminateswere prepared by vacuum assisted resin transfer molding. Both methods provide for
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through the thickness infusion by either the insertion of resin flow pathways or by
utilizing a metal deposited layer with porosity. The VARTMFMLs provide good
mechanical properties that can be optimized by proper selection of metal foil, fiber, resin
and size and distribution of the pathways. The VARTMPCLs allow the incorporation of a
plasma deposited metal layer that can improve functional properties like electrical and
thermal conductivity.[23]
In 2011, J.M. Balvers, H.E.N. Bersee, A. Beukers working on SETTLING OF GLASS
WOVEN FABRIC IN STEEL RTM MOULD: IMPACT ON RESIDUAL STRESSES
they stated that With embedded fibre Bragg grating sensors it is proven that thermal
loading of steel RTM mould containing glass woven fabrics leads to different behavior
when fabric still has to settle. Heating and cooling along the same trajectory do not imply
a reversible process with respect to expansion/contraction of the preform.
After completing their research they concluded whether thermal loading has an influence
on residual strain can now be answered when looking at following Table 2.1 and Figure
2.1.
Table 2.1: Slope of 'Locus of zero stress'-line (10-6K-1)
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(a) (b)
Figure 2.1 Residual strain in woven glass fabric
(a) Without thermal loading (090403),
(b) With thermal loading (090401)
Although on average the residual strain curves for each panel coincided, less spread in
experimental data was observed for the panel that had undergone thermal loading. Since
none of the other process parameters or inputs were intentionally altered, it may be
concluded that thermal loading did not change the residual strain curve significantly, but
resulted in less spread in experimental data between the specimens mutually. This could
also have influences on the scatter in mechanical properties. However, after analyzing the
specimens that were annealed, it turned out that some of the optical fibres were not
perfectly aligned with the fibres of the reinforcement. A maximum angle of 2 was
measured for one of the specimens. This small misalignment can also be the cause of the
spread in experimental data. If the spread was due to the misalignment, one can conclude
that the observation of settling and the approach of thermal loading did not influence the
residual strain. [24]
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CHAPTER NO. 3
FABRICATION OF MOULD
3.1 INTRODUCTION
It is a shaped cavity used to give a definite form to fluid or plastic material or Mould is a
frame on which something may be constructed. It may be a hollow container used to
give shape to molten or hot liquid material when it cools and harden known as mould.
3.2 HISTORY
The art of mould making has been around for centuries and since the demand for mould
making has increased over that time so has the demand for Mould Maker. Mould makers
is a career in which the person creates tools, moulds and parts for products and machinery
that we use in our everyday lives. Mould makers use many different types of tools to aid
them such as lathes, grinders, and mills. A lathe is a machine tool for shaping metal or
wood, the lathe works by turning about a horizontal axis against a fixed tool. The lathewas first invented by John Wilkinson in 1775. The lathe that Wilkinson created was a
tool that cut holes in metal that was then used in steam engines. Eli Whitney in 1818
invented the first mill. A mill is a device that is designed to break a solid material into
smaller pieces. There are many different types of grinding mills and many types of
materials processed in them. The mill created by Whitney allowed more mould makers
and machinists to produce parts and tools much faster and with less skill.
3.3 PROCESS OF MOULD
Moulding is the process of manufacturing by shaping pliable raw material as fluid, glass,
ceramic material etc using a rigid frame or model called a pattern to form any desired
shape of object.
3.4 TYPES OF MOULD
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There are main two types of molds given below
3.4.1 Expendable Mould or One Use Mould
This type of mold includes sand, plastic, shell, and investment (lost-wax technique)mouldings. All of these involve the use of temporary and no reusable moulds, and need
gravity to help force molten fluid into casting cavities. In this process the mould is used
only once.
3.4.2 Nonexpendable Mould or Permanent Mould
This mold differs from expendable mould in that the mould need not be reformed after
each production cycle. This technique includes at least four different methods:permanent, die, centrifugal, and continuous casting.
3.5 FABRICATION OF MOULD
The mould which we need for our research is a Nonexpendable mould or permanent
mould and can be fabricated by using acrylic sheet (transparent hard sheet) and M.S
(mild steel) and Procedure for fabrication of our required mold is defined below:
3.5.1 Cutting of Acrylic Sheet for Mould
We took and done all the following steps and processes for the fabrication of transparent
sheets shown in figure 3.1 for moulds:
First of all we cut acrylic sheet of the square measurement of 381mm381mm by
machine saw.
Than we made square root of measurement of 8mm width8mm depth by leaving
the distance of 38.1mm from all four edges with the help of milling machine.
After that process we made three holes by drilling process of the measurement of
9mm one on the centre of whole transparent sheet and other two holes on the
opposite edges of transparent sheet by leaving space of 38.1mm and taking the
centre of that corner side.
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Finally after drilling process we made threads with the help of tap of 10mm in the
holes drilled near to two opposite edges and 20mm for central hole and fixed
small copper pipes into holes
Figure 3.1 Bottom Sheet and Top Sheet
3.5.2 Fabrication of Vises for Holding and Tightening the Transparent Sheets
For making of vise, first of all we will took 5mm thick M.S (mild steel) sheet than
we cut it of the measurement 114.3mm width 381 lengths on shearing machine
as shown in figure 3.2.
Figure 3.2 Shearing Machine
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After this we bent it by both edges on hydraulic brake press bending machine
shown in figure 3.3of the 25.4 measurement.
Figure 3.3 Ilam Din Hydraulic brake press bending machine
After this with same process we cut M.S (mild steel) bar on shearing machine of
12.7mm width 381mm length then we temporary welded the M.S (mild steel)
sheet and bar on either edge of sheet as shown in figure 3.4.
Figure 3.4 Temporary welded bar with M.S Sheet
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After this process with the help of drilling machine shown in figure 3.5, we made
three holes one on the centre, means we drilled by leaving the distance of
190.5mm from either edges of the measurement of 6.35mm tip and other two on
both edges leaving the distance of 50.8mm with the same measurement of 6.35drill, We make threads with the help of tap 9.525mm into the drilled holes by
holding the mold in bench vise as shown in figure 3.6.
Figure 3.5 AMK-13E radial drilling & boring machine
Figure 3.6 Holes drilled into vise
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We made two holes of the measurement of 9.525mm leaving the distance of
120.65mm from both corner sides of sheet for making pin joints for sliding of
inner M.S bar as shown in figure 3.7.
Figure 3.7 Vise making pin joint with M.S bar
Finally we hold the vise on shaper machine shown in figure 3.8 for making the
fleet on both edges with the help of try square putting it at 450
, after that for
removing chips, smoothness and removing extra material from vise by grinder
machine also by filing process.
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Figure 3.8 SHAPING MACHINE
After fabrication of top sheet and bottom sheet and holding vises, we tightened
the both sheets in vises, we obtained the mould shown in figure 3.9.
Figure 3.9 Fabricated Mould
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CHAPTER NO: 04
SAMPLE DEVELOPMENT
4.1 RATIO:
The ratios of the items by which samples are developed are following:
Vinyl Ester: This is a resin (matrix) material.
Cobalt: This is a catalyst material and it was used to increase the rate of reaction.
MEKP: This is a hardener material and was used in reaction with resin
Fabric (glass fabric 200mg): The standard dimension for the glass fabrics sheet
is 304.48mm/304.48mm.
4.2 PREPARATION FOR SAMPLE DEVELOPMENT
Following methods were used for development of samples:
1. Bottom Sheet
Applying vex on whole sheet
Placing sealing sheet strips on all four sides of sheet for stopping air
interruption.
Placing fabrics of 304.48mm/304.48mm on sheet
Figure 4.1 Bottom Sheet with Vex applied and Placed Sealing Sheet
2. TOP Sheet
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Proceeding same process, we apply vex on whole sheet also on roots of sheet.
3. Placement of Top Sheet upon Bottom Sheet
After vex on top sheet we place top sheet upon the bottom sheet clearly
because the placement of vises will be with good manner.
4. All Sides of Sheets have been tightened by Vices
Each vice is placed in sides of sheet and bolts of vice are tightened by key
clearly because of no air crossing occurs.
Figure 4.2 Sheets tightened by Vices
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5. Connect the mould to vacuum
The function of vacuum is to remove the air so when air is removed we use
chuck plass on vacuum pipe.
Figure 4.3 Mould connected to vacuum pump
6. Resin preparation
We mixed up the resin, cobalt and MEKP hardener with proper ratio in a
beaker and then we continuously mixed it as it must not become solid.
7. All prepare resin is vacuumed in mould
At first vacuum the whole mould with the help of vacuum pump from
working space than allow the resin to mould cavity.
8. De mould
After 24-hours we demoulded the sample.
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In this our research, we developed following seven composite samples for testing tensile
behavior and we will conduct tensile test of simple glass fabric.
4.3 MOULD A
Two layers (+45,-45) of fabric glass were used to develop the sample shown in figure
4.4.
Figure 4.4 Mould A
4.4 MOULD B
Two layers (0/90and + 45) of fabric glass were used to develop the sample shown in
figure 4.5.
Figure 4.5 Mould B
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4.5 MOULD C
Alternate four layers of (0/90 and + 45) of fabric glass were used to develop thesample shown in figure 4.6.
Figure 4.6 Mould C
4.6 MOULD D
Four layers of ( +45 ) of fabric glass were used alternatively to develop the sample
shown in figure 4.7.
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Figure 4.7 Mould D
4.7 MOULD E
Four layers of (0/90) of fabric glass were used to develop the sample shown in figure4.8.
Figure 4.8 Mould E
4.8 MOULD F
Two layers of (0/90) of fabric glass were used to develop the sample shown in figure
4.9.
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Figure 4.9 Mould F
4.9 MOULD G
Two layers of (0/ 90) of fabric glass were used and resin was transferred by hand layupRTM to develop the sample as shown in figure 4.10.
Figure 4.10 Hand layup Mould
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CHAPTER NO. 05
TESTING AND RESULT DISCUSSION
Development of composite material is crucial issue due to their mechanical properties
and application. Efforts are being made to locally develop a composite material in the
laboratory of Mechanical Engineering Department by using vacuum assisted resin
transfer mold. Fabric glass was selected in composite material. Secondly resin which is a
matrix material is also selected from market. In this experimental study we have tested
fabric glass with multi oriented arrangements and laminates with vinyl ester resin.
In this chapter we conducted tensile testing of developed samples on UTS machine
(detailed given in section 6.1) and those samples are detailed in previous chapter. Tensile
testing on UTS machine was used to carry out various tests. Following tests were
conducted UTS machine in laboratory for this developed composite material.
A) Tensile stress
B) Youngs modulus of elasticity
C) Breaking elongation %
D) Percentage elongation
We cut two strips of 1 width of each from each developed samples to achieve good and
correct results. In this chapter we present a complete discussion in order to clarify the
obtained results.
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5.1 SSTM-20KN TESTING MACHINE
The united SSTM-20KN testing machine is a mechanical type, Universal Testing
Machine shown in following figure. It is a computer inclusive, electromechanical, test
system designed to accommodate a variety of testing instruments and accessories to
conduct various tests such as Impact test, Hardness test, simple tensile test, shear stress
test, uniaxial test etc of various types of material including ceramics, plastics, polymers,
metals and composites.
SSTM-20KN Testing Machine
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5.2 TEST SPECIMEN OF COMPOSITE MATERIAL A.
Sample was developed by vacuum assisted resin transfer mold (VARTM). Duringexperimentation it was difficult to maintain the thickness of specimen so we took three
points for taking uniform thickness. Two layers ( ) of fabric glass were used as a
fabric material and vinyl ester resin as matrix material was used, this composite specimen
is divided into two parts equal length and equal width.
5.2.1 Test Specimen of Composite Material A1
Specimen A1 is the strip cut from the composite material sample A1 and is shown in
figure 5.1(a) before test and in figure 5.1(b) after test.
.
Figure 5.1(a) Composite material test specimen A1(before test).
Figure 5.1(b) Composite material test specimen A1(after test).
The specifications of specimen A1 shown in figure 5.1(a) of developed composite
material sample A are shown in table 5.1.
Table: 5.1 Specifications of Composite material specimen A1.
Name of specimen Length width thickness
Point A Point B Point C
A1 254 25.4 1.20 1.15 1.10
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All the specifications are in mm.
Specimen A1 of Composite material sample A were tested in tensile testing machine, fig:
5.1(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen A1.
Figure 5.1(C) Observation graph and results for composite material specimen A1.
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5.2.2 Test Specimen of Composite Material A2
Specimen A2 is the strip cut from the composite material sample A and is shown in
figure 5.2(a) before test and in figure 5.2(b) after test.
Figure 5.2(a) Composite material test specimen A2 (before test).
Figure 5.2(b) Composite material test specimen A2 (after test).
The specifications of specimen A2 shown in figure 5.2(a) of developed composite
material sample A are shown in table 5.2.
Table: 5.2 Specifications of Composite material specimen A2.
Name of specimen Length width Thickness
Point A Point B Point C
A2 254 25.4 1.25 1.00 0.9
All the specifications are in mm.
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Specimen A2 of Composite material sample A were tested in tensile testing machine, fig:
5.2(c) shows the graph in Stress v/s Extension of tensile test conducted in the laboratory
for test specimen A2.
Figure 5.2(C) Observation graph and results for composite material specimen A2.
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5.3 TEST SPECIMEN OF COMPOSITE MATERIAL B
Sample was developed by vacuum assisted resin transfer mold (VARTM). During
experimentation it was difficult to maintain the thickness of specimen so we took three
points for taking uniform thickness. Two layers ( 45, 0/ 90) of fabric glass were used
as a fabric material and vinyl ester resin as matrix material was used, this composite
specimen is divided into two parts equal length and equal width.
5.3.1Test Specimen of Composite Material B1
Specimen B1 is the strip cut from the composite material sample B and is shown in figure
5.3 (a) before test and in figure 5.3(b) after test.
Figure 5.3(a) Composite material test specimen B1 (before test).
Figure 5.3(b) Composite material test specimen B1(after test).
The specifications of specimen B1 shown in figure 5.3 (a) of developed composite
material sample B are shown in table 5.3.
Table: 5.3 Specifications of Composite material specimen B1
Name of specimen Length width Thickness
Point A Point B Point C
B1 254 25.4 1.30 1.05 1.15
All the specifications are in mm
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Specimen B1 of Composite material sample B were tested in tensile testing machine, fig:
6.3(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen B1.
Figure 6.3 (C) Observation graph and results for composite material specimen B1
5.3.2 Test Specimen of Composite Material B2
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Specimen B2 is the strip cut from the composite material sample B2 and is shown in
figure 5.4 (a) before test and in figure 5.4(b) after test.
Figure 5.4 (a) Composite material test specimen B2 (before test).
Figure 5.4(b) Composite material test specimen B2 (after test).
The specifications of specimen B2 shown in figure 5.4(a) of developed composite
material sample B are shown in table 5.4.
Table: 5.4 Specifications of Composite material specimen B2
Name of specimen Length width thickness
Point A Point B Point C
B2 254 25.4 1.10 1.00 1.15
All the specifications are in mm.
Specimen B2 of Composite material sample B was tested in tensile testing machine,
fig:5.4(c) shows the graph in Stress v/s Extension and results of tensile test conducted in
the laboratory for test specimen B2.
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Figure 5.4 (C) Observation graph and results for composite material specimen B2
5.4 TEST SPECIMEN OF COMPOSITE MATERIAL C
Sample was developed by vacuum assisted resin transfer mold (VARTM). During
experimentation it was difficult to maintain the thickness of specimen so we took three
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points for taking uniform thickness. Alternate four layers of ( 45, 0/90) of fabric glass
were used as a fabric material and vinyl ester resin as matrix material was used, this
composite specimen is divided into two parts equal length and equal width.
5.4.1Test specimen of composite material C1
Specimen C1 is the strip cut from the composite material sample C and is shown in figure
5.5(a) before test and in figure 5.5(b) after test.
Figure 5.5 (a) Composite material test specimen C1(before test).
Figure 5.5 (b) Composite material test specimen C1 (after test).
The specifications of specimen C1 shown in figure 5.5(a) of developed composite
material sample C are shown in table 5.5.
Table: 5.5 Specifications of Composite material specimen C1
Name of specimen Length width thickness
Point A Point B Point C
C1 254 25.4 1.20 1.30 1.05
All the specifications are in mm.
Specimen C1 of Composite material sample C was tested in tensile testing machine, fig:
5.5(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen C1.
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Figure 5.5 (C) Observation graph and results for composite material specimen C1
5.4.2 Test Specimen of Composite Material C2
Specimen C2 is the strip cut from the composite material sample C and is shown in figure
5.6 (a) before test and in figure 5.6(b) after test.
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Figure 5.6 (a) Composite material test specimen C2 (before test).
Figure 5.6 (b) Composite material test specimen C2 (after test).
The specifications of specimen C2 shown in figure5.6(a) of developed composite
material sample C are shown in table 5.6.
Table: 5.6 Specifications of Composite material specimen C2
Name of specimen Length width thickness
Point A Point B Point C
C2 254 25.4 1.00 0.9 0.95
All the specifications are in mm.
Specimen C2 of Composite material sample C was tested in tensile testing machine, fig:
5.6(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen C2.
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Figure 5.6 (C) Observation graph and results for composite material specimen C2
5.5 TEST SPECIMEN OF COMPOSITE MATERIAL D
Sample was developed byvacuum assisted resin transfer mold (VARTM). During
experimentation it was difficult to maintain the thickness of specimen so we took three
points for taking uniform thickness. Four layers of ( 45) of fabric glass were used
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alternatively as a fabric material and vinyl ester resin as matrix material was used, this
composite specimen is divided into two parts equal length and equal width.
5.5.1Test Specimen of Composite Material D1
Specimen D1 is the strip cut from the composite material sample Dand is shown in figure
5.7(a) before test and in figure 5.7(b) after test.
Figure 5.7 (a) Composite material test specimen D1 (before test).
Figure 5.7 (b) Composite material test specimen D1 (after test).
The specifications of specimen D1 shown in figure 5.7(a) of developed composite
material sample D are shown in table5.7.
Table: 5.7 Specifications of Composite material specimen D1
Name of specimen Length width thickness
Point A Point B Point C
D1 254 25.4 1.05 0.9 1.00
All the specifications are in mm.
Specimen D1 of Composite material sample D was tested in tensile testing machine, fig:
5.7(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen D1.
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Figure 5.7 (C) Observation graph and results for composite material specimen D1
5.5.2 Test Specimen of Composite Material D2
Specimen D2 is the strip cut from the composite material sample D and is shown in
figure 5.8(a) before test and in figure 5.8(b) after test.
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Figure 5.8 (a) Composite material test specimen D2 (before test).
Figure 5.8 (b) Composite material test specimen D1 (after test).
The specifications of specimen D2 shown in figure 5.8(a) of developed composite
material sample D are shown in table 5.8.
Table: 5.8 Specifications of Composite material specimen D2
Name of specimen Length width thickness
Point A Point B Point C
D2 254 25.4 1.5 1.6 1.2
All the specifications are in mm.
Specimen D2 of Composite material sample D was tested in tensile testing machine, fig:
5.8(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen D2.
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Figure 5.8 (C) Observation graph and results for composite material specimen D2
5.6 TEST SPECIMEN OF COMPOSITE MATERIAL E
Sample was developed by vacuum assisted resin transfer mold (VARTM). During
experimentation it was difficult to maintain the thickness of specimen so we took three
points for taking uniform thickness. Four layers of (0/90) of fabric glass were used as a
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fabric material and vinyl ester resin as matrix material was used, this composite specimen
is divided into two parts equal length and equal width.
5.6.1Test Specimen of Composite Material E1
Specimen E1 is the strip cut from the composite material sample Eand is shown in figure
5.9 (a) before test and in figure 5.9(b) after test.
Figure 5.9 (a) Composite material test specimen E1 (before test).
Figure 5.9 (b) Composite material test specimen E1 (after test).
The specifications of specimen E1 shown in figure 5.9(a) of developed composite
material sample E are shown in table 5.9.
Table: 5.9 Specifications of Composite material specimen E1
Name of specimen Length width thickness
Point A Point B Point C
E1 254 25.4 2.1 1 1.5
All the specifications are in mm.
Specimen E1 of Composite material sample E was tested in tensile testing machine, fig:
5.9(c) shows the graph in Stress v/s Extension and results of tensile test conducted in the
laboratory for test specimen E1.
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Figure 5.9 (C) Observation graph and results for composite material specimen E1
5.6.2 Test Specimen of Composite Material E2
Specimen E2 is the strip cut from the composite material sample E and is shown in figure
5.10 (a) before test and in figure 5.10(b) after test.
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Figure 5.10 (a) Composite material test specimen E2(before test).
Figure 5.10 (b) Composite material test specimen E2(after test).
The specifications of specimen E2 shown in figure 5.10(a) of developed composite
material sample E are shown in table 5.10.
Table: 5.10 Specifications of Composite material specimen E2
Name of
specimen
Length width thickness
Point A Point B Point C
E2 254 25.4 2.1 1 1.5
All the specifications are in mm.
Specimen E2 of Composite material sample E was tested in tensile testing machine,
fig:5.10(c) shows the graph in Stress v/s Extension and results of tensile test conducted in
the laboratory for test specimen E2.
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Figure 5.10 (C) Observation graph and results for composite material specimen E2
5.7 TEST SPECIMEN OF COMPOSITE MATERIAL F
Sample was developed by vacuum assisted resin transfer mold (VARTM). During
experimentation it was difficult to maintain the thickness of specimen so we took three
points for taking uniform thickness. Two layers of (0/ 90) of fabric glass were used as a
fabric material and vinyl ester resin as matrix material was used, this composite specimen
is divided into two parts equal length and equal width.
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5.7.1Test Specimen of Composite Material F1
Specimen F1 is the strip cut from the composite material sample Fand is shown in figure
5.11 (a) before test and in figure 5.11(b) after test.
Figure 5.11 (a) Composi
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