7/28/2019 Composite Project b Tech[1]
1/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 1
CHAPTER-1
INTRODUCTION
1.1 Definition of composite material
Materials consisting of two or more distinct phases brought together, with a
recognizable definite interface, the constituent materials insoluble i.e. physically
separable resulting with the properties which are uniquely different compared to the
constituent materials showing synergism the presence of one material will make the other
to behave differently.
Two or more different constituent materials are together intimately mixing them
by various means which are acting together and performing together to yield enhance
property and quality superior to what is promised.
A substance consisting of two or more materials, insoluble in one another which,
are combined to form a useful engineering material processing certain properties not
possessed by the constituents. Something combining the typical or essential
characteristic of individuals making up a group.
1.2 Theory of composites
Composites are considered to be any multi-phased material that exhibits
significant properties of the properties of constituent phase. These are artificially made as
that of naturally occurs. These are used to produce extraordinary materials (ceramics,
polymers, and various materials.
This combination of materials to form a new material system with enhanced
material properties is well documented in history. For example, the Japanese warriors
were known to use laminated metals in the forging of their swords to obtain desirable
material properties. More recently, in the 20th century civil engineers placed steel rebar in
cement and aggregate to make a well-known composite material, i.e. reinforced concrete.
Their advantages over other materials for high-performance, lightweight
applications have attracted many industries such as aerospace, automobile, infrastructure,
sports and marine to explore and increase their usage.
7/28/2019 Composite Project b Tech[1]
2/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 2
1.3 The criteria to be met in composite material
1) The composite material must be man-made i.e. it should be manufactured one.
2) The composite material must be a combination or two or more physically and/or
chemical distinct materials with a distinct interface separable.
3) The composite materials must have the characteristic properties, which would not be
achieved by any of the constituent components acting alone, which have different
properties.
4) The constituents forming the composite must be intimately mixed or dispersed and
made as a homogeneous content.
5) Both constituents have to be present in reasonable proportions (at least>55%).
In general, for composites the following factors are very important.
1) Position and location of reinforcement.
2) Aspect ratio of the reinforcement (shape and dimensions).
3) Bonding has to be ensured between constituent materials.
1.4 The need of composite materials
1.The demand made by diverse field as space, aeronautics, civil construction and
automobiles, on materials to be forever better overall performance by one as single
material.
2. Due to the continuing quest for improved performance, by various criteria including
less weight more strength i.e. high strength to weight ratio and lower cost. For the
advantages of
a) Flexible design (for optimum design by providing fluidity to design).
b) Energy consciousness.
c) Extending the limit of usefulness.
3. To achieve enhanced property (or) to give the quality of product superior to that what
is promised.
Example of composites
1. Mud reinforced with straw (brick)
7/28/2019 Composite Project b Tech[1]
3/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 3
2. Mixture of stones, sand and cement (concrete)
3. Bamboo reapers and lake bed clay
1.5 Classification of composites
1.5.1 Fibrous composites
Fibrous composites consist of fibers of one material in a matrix of another. it may
be continuous or discontinuous fibers.
Example: Glass-epoxy
Glass-polyester
Kevlar-epoxy
Continuous & Discontinuous & Discontinuous &
Aligned fibers Aligned fibers Randomly
Aligned fibers
Figure 1: Fibrous composites
7/28/2019 Composite Project b Tech[1]
4/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 4
1.5.2 Particulate composites
Particulate composites are composed of macro-sized particles of one material in a
matrix of another, either metallic or non-metallic.
Examples: Sinter aluminum powder
Ceramic-composites (cermets)
Figure 2: Particulate composites
1.5.3 Laminated composites
Laminated composites are made up of different materials, including the
composites of the first two types.
Examples: Laminar composites
Sandwich panels
Figure 3: laminated composites
7/28/2019 Composite Project b Tech[1]
5/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 5
1.6 Categorization of composites
Composites can be categorized by matrix characteristics, including
1. Type
a. Metal
b. Ceramic
c. Polymeric
d. Rubber
2. Ceramic nature
a. Organic
b. Inorganic
3. Origin
a. Natural
b. Artificial4. Process ability
a. Thermo set
b. Thermoplastic
Composites can be categorized by their fiber characteristics, including
1. Type
a. Glass
b. Carbon (graphite)
c. Kevlar (aramid)
2. Fiber posting (or) Alignment
a. Random
b. Unidirectional
c. Bi-directional (woven)
7/28/2019 Composite Project b Tech[1]
6/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 6
1.6.1 Advanced composites
There are five principal types of advanced composites material in wide use.
The composite types, which includes polymer matrix composites (PMC), metal
matrix composites (MMC), ceramic matrix composites (CMC), carbon-carbon (CC) and
hybrid composites.
1.7 Hybrid composite materials
1.7.1 Definition
Composites containing more than one type of fiber are commonly known as
hybrid composites. The term hybrid is generally used to denote the incorporation of two
different types of material into one single material. And the level of mixing can be either
on a small scale (fiber, tows) or on a large scale (layers, pultrusions, ribs).
The purpose of hybridization is to construct a new material that will retain the
advantages of its constituents but not their disadvantages. However, for most properties,
the rule of mixtures (i.e. the weighted sum of the constituents properties according to the
composition) is only an upper bound. For example, in the case of tensile strength, the
stiffer material fails first at roughly its normal failure strain and therefore the hybrid is
weaker than both its constituents.
However, there are other factors such as cost, weight, post-failure behavior and
fatigue performance that sometimes lead the designer to the use of hybridization in order
to the exact needs of the structure under design.
7/28/2019 Composite Project b Tech[1]
7/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 7
1.7.2 Types of hybrids
There are several types of hybrid composites, characterized according to the way
in which the constituent materials are mixed.
1. Sandwich hybrids, also known as core-shell, in which one material is sandwiched
between two layers of another.
2. Intraply, or laminated, where alternate layers of the two (or more) materials are
stacked in a regular manner.
3. Itraply, or tow-to-tow, in which alternative layers of the two (or more) constituent
types of fiber are mixed in a regular or random manner.
4. Intimately mixed hybrids, where the constituent fibers are made to mix as
randomly as possible so that no concentrations of either type are present in the
material. And other kinds such as those reinforced with ribs, pultruded wires,
thin veils of fiber and combinations of the above.
1.7.3 Benefits of hybridization
1. Balance the cost with weight and performance.
2. Enhanced strain to failure as compared to pure single fiber.
3. Enhanced energy absorption to failure and hence fails gradually.
4. Improved fatigue strength.
5. Flexural strength can be improved.
6. Improved impact strength.
1.8 Advantages of composite materials
1) Light in weight.
2) High strength to weight ratio.
3) Low density.
4) Excellent directional strength.
5) Good weather resistance.
6) Greater fatigue resistance than steel or aluminum.
7) Greater design flexibility than homogeneous materials.
7/28/2019 Composite Project b Tech[1]
8/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 8
8) Potential for corrosion is significantly reduced.
9) Minimize part count.
10)Good electric insulation.
11)Low sound transmission.
12)Low thermal conductivity and low thermal coefficient of thermal expansion.
13)Radar transparency.
14)Non-magnetic.
1.9 Applications of composite materials
Some of the applications of composite materials in industries are as listed in the
table.
Industry Successful application
Transportation Passenger car, highway tractors, truck body, trailers,
recreation vehicles, floor for rail cars, etc.
Aircraft industry Fuselage, wing, rotor blades, cargo pods, engine cowls,
boosters, satellites, helicopters, high strength turbine blades.Marine Pleasure boats, workboats, commercial vessels, hovercraft,
hydrofoils, and submarines.
Building House roofs, modern structures, and tanks.
Chemical Piping, ducts, hood stacks and storage tank.
Appliances and
Equipment
Tanks, air condition frames, condenser fans, valves, chasses,
containers and other components.
Electrical Electrical contacts, electrodes, low expansion pcb in lamps.Sports Tennis racquets, golf club shafts, fishing rods, snow skis
water skis, hokey sticks and arrows.
Medicine Artificial limbs, dentures, etc.
Table 1: General applications of composite material
7/28/2019 Composite Project b Tech[1]
9/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 9
Apart from these specific applications, the use of fiber reinforced plastics
(FRP) composite material is also being explored in automobile industry, sports
industry, windmills etc. most of the demand of modern society, which normally
require material having high strength and stiffness at reduced weights and cost are
being satisfied by composite materials.
Applications of composite in aerospace
Sl.No Aircraft Principal components
1 Air bus a-300 Rudder, outboard spoiler, vertical fin,
cabin vertical support rods, main landing
gear fairing.
2 Boeing 737 Horizontal stabilizer.
3 Boeing 747 Outboard aileron engine inlet and outlet
cowl, floor panels.
4 Mirage 2000 Fin equipped with radar, front landingdoor, and access and inspection doors.
5 light combat aircraft (LCA)
India
Rudder, vertical fin, wings.
6 NALS light aircraft HANSA
(India)
Complete airframe structure (gfrp-foam
sandwich).
7 NALS 14 seated light aircraft
SARAS (India)
Composites of flight control systems of
rudder, elevator, flifs, etc.
Table 2: Applications of composite material in aircrafts
7/28/2019 Composite Project b Tech[1]
10/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 10
CHAPTER -2
REVIEW OF LITERATURE
2.1 Different forms of reinforcement
1) Strands: a collection of filaments, the basic from in which fiber is produced.
2) Yarns: twisting the strands makes yarns.
3) Roving: the collection of strands made in tape like form without twisting.
4) Unidirectional cloth: roving is aligned in warp, a mat from with minimum wet
fiber.
5) Woven roving mat: roving is woven with fiber in warp and weft directions.
6) Continuous strand mat: strands are randomly oriented and bonded to other with
a binder.
2.2 Different structures of woven fabrics
A fabric is material constructed of inter laced yarns, fibers or filament and is
usually planer in structure. Interlacing individually are filaments, ends, yarns and
rowing makes a woven reinforced fabric. Woven reinforcements consist of orthogonal
fiber. The long direction of the fibers is called the warp while the width direction of the
fiber is called the fill, weft or woof. Fills are also called picks. The weave of the fabric
refers how to warp yarn and weft yarn are inter laced.
The fabric composites have low fiber to volume ratio, which contributes to the
low elastic moduli and strength properties. The major fabric types are twill weave, stain
weave, leno weave, plain weave, and triaxial weaves.
7/28/2019 Composite Project b Tech[1]
11/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 11
2.2.1 Plain weaves
Figure 4: Plain weaves
The plain weave is the oldest and most common textile weaves. One warp end is
repeatedly woven over one fill yarn and under the next. Plain weave being the most inter
laced is the firmest. The most stable construction providing porosity and minimum
slippage. The strength is uniform in both directions and is most resistant to in plane shear
movement. Though very stable, plain weave are relatively in efficient and have poor drag
i.e., they do not conform easily to surface to double curvatures.
2.2.2 Twill weaves
Figure 5: Twill weaves
Twill weaves are one or more warp ends passing over and fewer than two, three or
more fill pieces in regular pattern. These fabrics have characteristics diagonal patterns
known as twill lines. Twill weaves are relatively stable and structurally efficient than
plain weaves and have relatively good drape.
2.2.3 Stain weaves
Figure 6: Stain weaves
http://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.textum.com/images/leno.gif&imgrefurl=http://www.textum.com/weaves/&usg=__bi6PCHA0Qa5RjqPZ-x4FcZ8fOao=&h=123&w=125&sz=4&hl=en&start=5&tbnid=ZdJUclbKJKJCyM:&tbnh=89&tbnw=90&prev=/images?q=leno+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.fabrics.net/colpics/1001/photo3.jpg&imgrefurl=http://www.fabrics.net/joan1101.asp&usg=__sb8eOsrvqd61jtFkvSMF8E5pWg0=&h=220&w=210&sz=39&hl=en&start=2&tbnid=FGGzSWi0iw5FkM:&tbnh=107&tbnw=102&prev=/images?q=leno+weave&hl=enhttp://www.google.co.in/imgres?imgurl=http://www.lockergroup.com/images/content/buyguide/FIG2-TwillWeave.jpg&imgrefurl=http://www.lockergroup.com/buyersguide/&h=224&w=200&sz=15&tbnid=e1tSQBkUKP0Z8M::&tbnh=108&tbnw=96&prev=/images?q=twill+weave&hl=en&usg=__XvXfmMc-Gx7NLAiJ2VhRe0pdV0c=&ei=NVSiSce_LJDG6gOMmICtCg&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Twill_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&h=648&w=687&sz=80&tbnid=T2uiOwd631k0cM::&tbnh=131&tbnw=139&prev=/images?q=twill+weave&hl=en&usg=__0E6PbtKofZwA0rJPPNQ8lX-PIJA=&ei=AFGiSaiFMMzPkAWOsaXJCw&sa=X&oi=image_result&resnum=1&ct=image&cd=1http://images.google.co.in/imgres?imgurl=http://www.finemeshmetals.co.uk/images/Plain_Weave.JPG&imgrefurl=http://www.finemeshmetals.co.uk/wovenwire.htm&usg=__RHO8KEZ17i-V1T0XUTumWKX0ABs=&h=648&w=687&sz=90&hl=en&start=1&um=1&tbnid=wEIWpihgO-7EaM:&tbnh=131&tbnw=139&prev=/images?q=plain+weave&um=1&hl=en&sa=Xhttp://images.google.co.in/imgres?imgurl=http://www.tech.plym.ac.uk/sme/mats324/Figures/C2%20plainweave.jpg&imgrefurl=http://www.tech.plym.ac.uk/sme/MATS324/MATS324C2%20fabrics.htm&usg=__9ZoH5EXNoKlbDG4ZoDktDLtko0o=&h=588&w=569&sz=203&hl=en&start=2&um=1&tbnid=NiwScPHzX46LIM:&tbnh=135&tbnw=131&prev=/images?q=plain+weave&um=1&hl=en&sa=X7/28/2019 Composite Project b Tech[1]
12/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 12
The stain weave represents a family of constructions with a minimum of inter
lacing. In these the weft yarns are periodically skip or float over several warp yarns. Stain
weaves can be produced as standard of 4.5 or 8 harness forms. The stain weave is more
reliable than the plain weave as the floating yarns that are not woven in fabric creating a
considerable suppleness and looseness. It conforms readily to compound curves can be
woven into a very high density. This is because the weave produces a construction with
low resistant shear distortion. This is one reason why stain weaves are preferred for many
aerospace applications. But as the number of harness increases, so the float lengths and
degree of looseness and sleaziness making the fabric more difficult to control during
handling operations.
2.2.4 Leno weaves
Figure 7: Leno weaves
To have an advantage over the very light fabrics that tend to sleazy the leno weave
fabrics are introduced .in this type of construction, two or more wrap yarns cross over
each other, locking fill place .the leno weaves help to prevent the un reviling during
handling operations but is unsteadily for obtaining good laminate physical properties.
2.2.5 Tri axial weaves
Figure 8: Tri axial weaves
A few fabrics with non-orthogonal fiber orientation have been developed. One of
them is tri axial weave is called do weave .so the pattern consists of weave of weave in
http://images.google.co.in/imgres?imgurl=http://hexdome.com/weaving/triaxial/graphics/triaxial.jpg&imgrefurl=http://hexdome.com/weaving/triaxial/spheres/&usg=__YClrgWJVXTVKhh8GJ1l1-Bvs-v8=&h=314&w=401&sz=12&hl=en&start=2&tbnid=7KSACnvIt4qh7M:&tbnh=97&tbnw=124&prev=/images?q=triaxial+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.cstsales.com/media/weave/4_harness_satin.gif&imgrefurl=http://www.cstsales.com/weave_styles.html&usg=__08nYeyFD-wyEVW_ImR7qmn63HsM=&h=155&w=172&sz=2&hl=en&start=3&tbnid=g3ys2C03Y5xgDM:&tbnh=90&tbnw=100&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.auf.asn.au/const_images/weave_satin.jpg&imgrefurl=http://www.auf.asn.au/scratchbuilder/composites.html&usg=__13KbZNLPD0eNHqCrZXEWENt7v_E=&h=92&w=120&sz=8&hl=en&start=6&tbnid=z89oOSWXQ-LAgM:&tbnh=67&tbnw=88&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://hexdome.com/weaving/triaxial/graphics/triaxial.jpg&imgrefurl=http://hexdome.com/weaving/triaxial/spheres/&usg=__YClrgWJVXTVKhh8GJ1l1-Bvs-v8=&h=314&w=401&sz=12&hl=en&start=2&tbnid=7KSACnvIt4qh7M:&tbnh=97&tbnw=124&prev=/images?q=triaxial+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.cstsales.com/media/weave/4_harness_satin.gif&imgrefurl=http://www.cstsales.com/weave_styles.html&usg=__08nYeyFD-wyEVW_ImR7qmn63HsM=&h=155&w=172&sz=2&hl=en&start=3&tbnid=g3ys2C03Y5xgDM:&tbnh=90&tbnw=100&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.auf.asn.au/const_images/weave_satin.jpg&imgrefurl=http://www.auf.asn.au/scratchbuilder/composites.html&usg=__13KbZNLPD0eNHqCrZXEWENt7v_E=&h=92&w=120&sz=8&hl=en&start=6&tbnid=z89oOSWXQ-LAgM:&tbnh=67&tbnw=88&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://hexdome.com/weaving/triaxial/graphics/triaxial.jpg&imgrefurl=http://hexdome.com/weaving/triaxial/spheres/&usg=__YClrgWJVXTVKhh8GJ1l1-Bvs-v8=&h=314&w=401&sz=12&hl=en&start=2&tbnid=7KSACnvIt4qh7M:&tbnh=97&tbnw=124&prev=/images?q=triaxial+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.cstsales.com/media/weave/4_harness_satin.gif&imgrefurl=http://www.cstsales.com/weave_styles.html&usg=__08nYeyFD-wyEVW_ImR7qmn63HsM=&h=155&w=172&sz=2&hl=en&start=3&tbnid=g3ys2C03Y5xgDM:&tbnh=90&tbnw=100&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.auf.asn.au/const_images/weave_satin.jpg&imgrefurl=http://www.auf.asn.au/scratchbuilder/composites.html&usg=__13KbZNLPD0eNHqCrZXEWENt7v_E=&h=92&w=120&sz=8&hl=en&start=6&tbnid=z89oOSWXQ-LAgM:&tbnh=67&tbnw=88&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://hexdome.com/weaving/triaxial/graphics/triaxial.jpg&imgrefurl=http://hexdome.com/weaving/triaxial/spheres/&usg=__YClrgWJVXTVKhh8GJ1l1-Bvs-v8=&h=314&w=401&sz=12&hl=en&start=2&tbnid=7KSACnvIt4qh7M:&tbnh=97&tbnw=124&prev=/images?q=triaxial+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.cstsales.com/media/weave/4_harness_satin.gif&imgrefurl=http://www.cstsales.com/weave_styles.html&usg=__08nYeyFD-wyEVW_ImR7qmn63HsM=&h=155&w=172&sz=2&hl=en&start=3&tbnid=g3ys2C03Y5xgDM:&tbnh=90&tbnw=100&prev=/images?q=satin+weave&hl=enhttp://images.google.co.in/imgres?imgurl=http://www.auf.asn.au/const_images/weave_satin.jpg&imgrefurl=http://www.auf.asn.au/scratchbuilder/composites.html&usg=__13KbZNLPD0eNHqCrZXEWENt7v_E=&h=92&w=120&sz=8&hl=en&start=6&tbnid=z89oOSWXQ-LAgM:&tbnh=67&tbnw=88&prev=/images?q=satin+weave&hl=en7/28/2019 Composite Project b Tech[1]
13/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 13
a fashion with a straight yarn in between them. The major disadvantages of these
constructions are that does not have stableness and tear resisting.
2.3 Fiber reinforcement
Different types of reinforced fibers are
1) Glass fibers
2) Carbon fibers
3) Kevlar fibers
4) Boron fibers
2.4 Glass fibers
Fiber of a base material such as glass is muchstiffer and stronger thana bulk glass
itself. This is because crystal in a fiber are aligned along the axis and have only very few
internal defects such as cracks in the material. Fibers and drawing through a small die.
Glass fibers are supplied in the form of slightly twisted yarns consisting of groups of
parallel strands of fibers.
2.4.1 Properties
1) Superior tensile strength.
2) Perfect elasticity.
3) Attractive thermal properties.
4) Excellent moisture resistance.
5) Outstanding dimensional stability.
6) Excellent corrosion resistance.
7) Excellent electrical characteristics.
8) Low cost.
7/28/2019 Composite Project b Tech[1]
14/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 14
2.5 Different types of glass fiber
2.5.1 E-glass (E-electrical)
This is a lime-alumina borosilicate glass designed for electricity application. it has
high bulk and surface electrical resistivity. It has a near eutectic composition of si, al 2o3
and cao system e-glass developed to have,
1) High bulk electrical resistivity.
2) High surface resistivity.
3) Good fiber forming characteristics.
Pyrex composition glass, has good electrical properties and suitable for general
application when a combination of good strength and chemical resistance is required.
Over 90% of fibreglasses used for reinforcement are e-glass type. This glass bonds well
to most polymeric resins after an appropriate coupling agent is employed.
2.5.1.1 General properties of E-glass
1) Density =2.540.03gm/cm3.2) Is very important is any glass working process and this is true in fiber drawing.
3) The temperature, at which the viscosity of glass fiber is 10 4.5 poise, is
determined from rate of elongation of stressed fiber. at the strain point for e-glass
is 507c.
4) Annealing point is around 657 c.
5) Youngs modulus e=10.5*10 6 psi.
6) Good tensile strength and melting history.
2.5.2 A-glass
It consists of soda-lime high alkali contents susceptible to moisture. it has limited
use
2.5.3 C-glass
This has better corrosion resistance to acids than e-glass.
7/28/2019 Composite Project b Tech[1]
15/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 15
2.5.4 S-glass
It has higher tensile strength and modulus of elasticity than e-glass. It has got
superior strength, retention at elevated temperature and high fatigue limit (high cost).
2.5.5 D-glass
Low dielectric constant and is suited for high performance electronic applications.
2.6 Natural fibers in composites
With the rise of composite materials there is a renewed interest for natural fibers.
Their moderate mechanical properties prevent the fibers from using them in high-
performance applications, but for many reasons they can complete with glass fibers.
Natural fiber composites enjoy excellent potential as wood substitutes in building
industry in view of their low cost, easy availability, saving in energy and pollution free
production. Natural fibers, as a substitute for glass fibers in composite components, have
gained renewed interest the last decade, especially in automotive industries. Fibers like
flax, hemp or jute are cheap, have better stiffness per unit weight and have a lower impact
on the environment.
2.6.1 Advantages
1) Low specific weight, which results in a higher specific strength and stiffness than
glass. This is a benefit especially in parts designed for bending stiffness.
2) It is a renewable resource, the production requires little energy, and co 2 is given back
to the environment.
3) Producible with low investment at low cost, which makes the material an interesting
product for low-wage countries.
4) Friendly processing, no wear of tooling. Better working conditions, no skin irritation.
5) Thermal recycling is possible, where glass causes problems in combustion furnaces.
6) Good thermal and acoustic insulating properties.
7/28/2019 Composite Project b Tech[1]
16/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 16
2.6.2 Disadvantages
1) Lower strength properties, particularly its impact strength.
2) Variable quality, depending on unpredictable influences such as weather.
3) Moisture absorption, which causes swelling of the fibers.
4) Limited maximum processing temperature.
5) Lower durability, fiber treatments can improve this considerably.
6) Poor fire resistance.
7) Price can fluctuate by harvest results or agricultural politics.
8) Irregular fiber lengths; spinning is required to obtain continuous yarns.
2.7 Jute as a fiber material
Jute is a lingo-cellolosic best fiber obtained from the bark of two cultivated
species of the genus corchorus capsular is and of the family tiliaceae.jute is cultivated in
the alluvial plains in the tropical and sub-tropical zones of south Asian region jute textiles
are mainly used as packing materials because of their low cost, high strength and
stiffness. Jute has the advantage of being both renewable by agro-effects and environment
friendly due to bio-degradability. Non-traditional applications envisaged for jute include
decorative and furnishing fabrics, floor coverings woven and non-woven geo thermal and
sound insulation media and reinforced plastics and composites.
Although the tensile strength and youngs modulus of jute are lower than those of
glass fibers, the specific modulus of jute fiber is superior to that of glass and on a
modulus per cost basis, jute is for superior. The specific strength per unit cost of jute, too,
approaches that of glass. Therefore, where high strength is not a priority, jute may be used
to fully or new partially replace glass fiber without entailing the introduction of new
techniques of composite fabrication.
The need for using jute fibers in place of the traditional glass fiber partly or fully
as reinforcing agents in composites stems from its lower specific gravity (1.29) and
higher specific modulus (40 Gpa) of jute compared with those of glass (2.5&30 Gpa
7/28/2019 Composite Project b Tech[1]
17/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 17
respectively). Apart from much lower cost and renewable nature of jute, much lower
energy requirement for the production of jute (only 2 per cent of that for glass) makes it
attractive as a reinforcing fiber in composites.
The jute composites may be used in everyday applications such as lampshades,
suitcases, paperweights, helmets, shower and bath units. They are also used for covers of
electrical applications, pipes, post boxes, roof tiles, grain storage silos, panels for partition
& false ceilings, bio-gas containers, and in the construction of low cost, mobile or
prefabricated buildings which can be used in times of natural calamities such as floods,
cyclones, earthquakes, etc.
2.7.1 Properties of jute
1) Jute is very stiff fiber with very low extensibility.
2) Its co lour ranges from golden brown to dirty grey depending upon the quality of
the fiber.
3) It is lustrous in appearance and generally has a rough feel. Jute fibers contain
variable number of cells along their length. Hence, the value of filament strength
with in a sample varies widely.
4) Jute has a moisture regain value of 11%at 65% humidity. This is because of
presence of hemi-cellulous in jute.
Jute is mildly acidic in nature.
2.7.2 Effect of moisture
A major draw back associated with the application of jute fibers for reinforcementof resin matrices. Due to presence of hydroxyl and other polar groups in various
constituents of jute fiber, the moisture uptake is high (approx. 12.5 percent at 65 percent
relative humidity &20deg c) by dry fiber and 14.6 percent by wet fiber.
All this leads to (i) poor wet ability with resin and (ii) weak interfacial bonding
between jute fiber and the relatively more hydrophobic matrices. Environmental
7/28/2019 Composite Project b Tech[1]
18/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 18
performance of such composites is generally poor due to delamination under humid
conditions.
In order to develop composites with better mechanical properties and
environmental performance, it is necessary to impart hydrophobicity to the fibers by
chemical reaction with suitable coupling agents or by coating with appropriates resins.
Following means can do modification of jute and other natural cellulosic fibers;
chemical means, coating with polymeric solutions and graft copolymerization. The
hydroxyl groups of jute are blocked when chemically treated making the fibers more
hydrophobic.
Polymeric coating of jute fiber is highly effective in enhancing the reinforcing
character of jute fiber, giving as high as 20-40 percent improvements in flexural strength
and 40-60 percent improvements in flexural modulus. These modifications improve the
fiber-matrix resin wet ability and lead to improve bonding. Jute can be graft
copolymerized with vinyl monomers. Grafting of polyacrylonitrile (10-25 percent)
imparts 10-30 percent improvements in flexural strength and flexural modulus of the
composites.
2.7.3 Need for pre-treatment
The jute has property to absorb moisture. The moisture so absorbed can be
seriously being detrimental to the bonding of atoms between the polyester resins and
surface of the jute layers. This will lead to decreased strength of the finished laminate.
This is because the matrix has to effectively transfer maximum load onto the fibers.
If there is a premature cracking or failure of matrix material, then the failure of matrix
material, then there will be a failure of the interface mechanism leading to premature
failure of matrix material. The jute layers, which are cut to the required size, are weighed
using an electronic weigh balance.
The temperature of oven is maintained at 80 deg for a period of one hour. After
one hour oven is switched off and the jute layers are taken out and again weighed in
7/28/2019 Composite Project b Tech[1]
19/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 19
electronic balance. The new weight is noted down. The difference in initial weight and
new weight gives moisture content present in jute. The % of moisture is calculated using
the relation.
Moisture content =initial weight
final weight/final weight
Thus the moisture % by weight present in jute is determined.
7/28/2019 Composite Project b Tech[1]
20/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 20
CHAPTER-3
THERIOTICAL ANALYSIS
3.1 Matrix materials
Polymers are the most used for matrix than metal or ceramics. They are very poor
inductors of heat and electricity and are generally more resistant to ceramicals than
metals. Polymers are giant chain like structures of molecules with conveniently bonded
carbon atom forming the backbone of chain. The process of making large molecules
(polymers) from small ones (monometers) is called polymerization.
3.2 Functions of the matrix phase
1) It binds the fibers together and acts as a medium by which an externally applied
stress is transmitted and distributed to the fibers; only a very small proportion of
an applied load is sustained by the matrix phase.
2) The matrix material should be ductile.
3) The matrix should protect the individual fibers from fiber damage as a result of
mechanical abrasion and chemical corrosion with environment.
4) The matrix separates the fiber layers and by the virtue of its relative softness,
prevents crack propagation from fiber which otherwise may lead to premature
failure of the composite. The adhesive bonding force between the fiber pullout
and adequate bonding is essential for the effective transmittance of stress from
weak matrix to the strong reinforcement.
3.3 Catalyst and Accelerators
Catalysts are materials, which initiate the chemical reaction that cause the resin to
undergo phase transformation from liquid to solid. Accelerator increases the speed of the
catalytic action. The pot life and gel time depends upon the quantity of accelerator and
catalyst taken.
A wide range of catalysts, accelerators, systems are available for use with
polymers resin. The selection of proper catalyst and amount to use for applications
7/28/2019 Composite Project b Tech[1]
21/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 21
depends on the resin, the curing temperature, required working or pot life and the gel
time.
The most commonly catalyst is benzoyl peroxide, which is efficient, easy to
handle, readily soluble in monomeric styrene storable for long periods of the time without
the loss of activity and stable at room temperature. Cobalt naphtha late is used as
accelerator.
3.4 Resin systems
Any resin system for use in a composite material will require the following
properties
1) Good mechanical properties.
2) Good adhesive properties.
3) Good toughness properties.
4) Good resistance to environmental degradation.
3.4.1 Mechanical properties of the resin system
Figure 9: Stress-strain curve for an ideal resin system
The figure below shows the stress / strain curve for an ideal resin system.
The curve for this resin shows high ultimatestrength, high stiffness and a high strain
to failure. This means that the resin is initially stiff but at the same time will not suffer
from brittle failure.
7/28/2019 Composite Project b Tech[1]
22/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 22
It should also be noted that when a composite is loaded in tension, for the full
mechanical properties of the fiber component to be achieved, the resin must be able to
deform to at least the same extent as the fiber. The figure below gives the strain to
failure for e-glass, s-glass, aramid and high-strength grade carbon fibers on their own.
Here it can be seen that, for example, the s-glass fiber, with an elongation to break of
5.3%, will require a resin with an elongation to break of at least this value to achieve
maximum tensile properties.
Figure 10: Selection criteria for the ideal resin system for a fiber
3.4.2 Adhesive properties of the resin system
High adhesion between resin and reinforcement fibers is necessary for any resin
system. This will ensure that the loads are transferred efficiently and will prevent
cracking or fiber / resin debonding when stressed.
3.4.3 Toughness properties of the resin system
Toughness is a measure of a materials resistance to crack propagation, but in a
composite this can be hard to measure accurately. However, the stress /strain curve of the
resin system on its own provides some indication of the materials toughness. Genera lly
the more deformation the resin will accept before failure the tougher and more crack-
resistant the material will be. Conversely, a resin system with a low strain to failure will
7/28/2019 Composite Project b Tech[1]
23/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 23
tend to create a brittle composite, which cracks easily. it is important to match this
property to the elongation of the fiber reinforcement.
3.4.4 Environmental properties of the resin system
Good resistance to the environment, water and other aggressive substances,
together with an ability to withstand constant stress cycling, are properties essential to any
resin system. These properties are particularly important for use in a marine environment.
3.5 Resin types
The resins that are used in the fiber-reinforced composites can also be referred to
as polymers. All polymers exhibit an important common property in that they are
composed of long chain like molecules consisting of many simple repeating units .man
made polymers are generally called synthetic resins or simply resins. Polymers can be
classified under two types thermoplastic and thermosetting according to the effect of heat
on their properties.
Thermoplastics, like metals, soften with heating and eventually melt, hardening
again with cooling. This process of crossing the softening or melting point on the
temperature scale can be repeated as often as desired without any appreciable effect on
the material properties in either state. Typical thermoplastics include nylon,
polypropylene and abs, and these can be reinforced, although usually only with short,
chopped fibers such as glass.
Thermosettingmaterials, or, thermo sets, are formed from a chemical reaction in
situ, where the resin and hardener or resin and catalyst are mixed and then under go a
non-reversible chemical reaction to form a hard, infusible product. In some thermo sets,
such as phenolic resins, volatile substances are produced as by-products. Other
thermosetting resins such as polyester and epoxy, by mechanisms that do not produce any
volatile by products and thus are much easier to process. Once cured, thermo sets will not
7/28/2019 Composite Project b Tech[1]
24/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 24
become liquid again if heated, although above a certain temperature their mechanical
properties will change significantly. This temperature is known as the glass transition
temperature (Tg), and varies widely according to the particular resin system used, its
degree of cure and whether it was mixed correctly. Above the Tg, the molecular structure
of the thermo set changes from that of a rigid crystalline polymer to a more flexible,
amorphous polymer. This change is reversible on cooling back below the Tg. Above the
Tg properties such as resin modulus drop sharply, and as a result the compressive and
shear strength of the composite does too. Other properties such as water resistance and
color stability also reduce markedly above the resins Tg.
Although there are many different types of resin in use in the composite industry,
the majority of structural parts are made with three main types, namely polyester, vinyl
ester and epoxy.
3.5.1 Polyester resins
Polyester resins are the most widely used resin systems, particularly in the marine
industry. By far the majority of dinghies, yachts and workboats built in composites make
use of this resin system. Polyester resin is the preferred material in marine industries
marine due to its superior. Polyester resin is the preferred material in marine industries
marine due to its superior water resistance.
Polyester resins are of the unsaturated type. Unsaturated polyester resin is a
thermo set, capable of being cured from a liquid or solid state when subject to the right
conditions. It is usual to refer to unsaturated polyester resins as polyester resins, or
simply as polyesters. There is a whole range of polyesters made from different acids,
glycols and monomers, all having varying properties. For use in molding polyester resin
requires the addition of several ancillary products. These products are generally a catalyst,
an accelerator and additives such as pigments and fillers.
7/28/2019 Composite Project b Tech[1]
25/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 25
3.5.2 Epoxy resins
The large family of epoxy resins represents some of the highest performance
resins of those available at this time. Epoxies generally out-perform most other resin
types in terms of mechanical properties and resistance to environmental degradation,
which leads to their almost exclusive use in aircraft components. As a laminating resins
their increased adhesive properties and resistance to water degradation make these resins
ideal for use in applications such as boat building. Here epoxies are widely used as a
primary construction material for high-performance boats or as a secondary application to
sheath a hull or replace water-degraded polyester resins and gel coats.
The term epoxy refers to a chemical group consisting of an oxygen atom bon ded
to two carbon atoms that are already bonded in some way. the simplest epoxy is a three-
member ring structure known by the term alpha-epoxy or 1,2-epoxy. The idealized
chemical structure is shown in the figure below and is the most easily identified
characteristic of any more complex epoxy molecule.
Figure 11: Idealized chemical structure of a simple epoxy (ethylene oxide)
Usually identifiable by their characteristic amber or brown coloring, epoxy resins
have a number of useful properties. Both the liquid resin and the curing agents form low
viscosity easily processed systems. Epoxy resins are easily and quickly cured at any
temperature from 5c to 150c, depending on the choice of curing agent. One of the most
advantageous properties of epoxies is their low shrinkage during cure, which minimizes
fabric print-through, and internal stresses. High adhesive strength and high mechanical
properties are also enhanced by high electrical insulation and good chemical rsistance.
Epoxies find uses as adhesives, caulking compounds, casting compounds, sealants,
varnishes and paints, as well as laminating resins for a variety of industrial applications.
7/28/2019 Composite Project b Tech[1]
26/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 26
Epoxy resins are formed from a long chain molecular structure similar to vinyl
ester with reactive sites at either end. In the epoxy resin, however, epoxy groups instead
of ester groups form these reactive sites. The absence of ester groups means that the
epoxy resin has particularly good water resistance. The epoxy molecule also contains two
ring groups at its center which are able to absorb both mechanical and thermal stresses
better than linear groups and therefore give the epoxy resin very good stiffness, toughness
and heat resistant properties.
3.6 Typical structural matrix resins
Table 3: Typical structural matrix resins
ResinTensile
strength
(Mpa)
Tensilemodulus
(Mpa)
Tg(k)
Thermo sets
Epoxy 103.4 4.1 463
Bismaleimide 82.7 4.1 547
Polyamide 137.9 4.8 630
Thermoplastic
Polynylene 65.5 4.3 366
Polyetheretherketon 70.3 1.1 400
7/28/2019 Composite Project b Tech[1]
27/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 27
CHAPTER-4
EXPERIMENTAL INVESTIGATIONS
4.1 Fabrication techniques of composite materials
Various processes are available for making composite materials. The different
processes available for the fabrication of fiber-reinforced composites are
1) Hand lay-up
2) Vacuum bag moulding
3) Pressure bag moulding
4) Autoclave moulding:
4.1.1 Hand lay-up
Hand lay-up is the simplest process for making the composites laminates. The
selected fibers are wetted with resin and placed in the mould and entrapped air is removed
with rollers. Layers of glass and resin are added to build up to desired thickness and it is
normally allowed to cure at room temperature.
7/28/2019 Composite Project b Tech[1]
28/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 28
Figure 12: Hand lay-up process
4.1.2 Vacuum bag moulding
In this method vacuum is used to eliminate voids and force out entrapped air and
excess resin. The component is first lay up in the mould with the resin, over the layers. Aseries of bleeders is placed, to provide a permeable space between lay-up and bag for
escape of evacuated air. A suitable sealing material such as cellophane of nylon is placed
over the lay-up and sealed at the edges. Vacuum is draw-in on the bag formed by the film,
and a laminate is formed. In this technique pressure less than atmosphere is possible.
4.1.3 Pressure bag moulding
In pressure bag moulding, usually a rubber bag is placed over the lay-up and
then at the pressure is applied to eliminate voids; force out entrapped air and squeezes
the excess resin. In pressure bag moulding higher pressure of the order of 100-mpa are
possible. Laminate with better mechanical properties are obtained.
7/28/2019 Composite Project b Tech[1]
29/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 29
4.1.4 Autoclave moulding
Autoclave moulding is similar to vacuum bag moulding and it is a modification
of pressure bag moulding. Autoclave moulding refers to the process of lying of
reinforcing materials and resin matrix in required shape and quantity in suitable open
moulds and effecting the polymerization of the product with simultaneous application
of pressure, heat and vacuum. The entire operation is carried out in special equipment
called autoclave, which is essentially a pressure vessel with heating and evacuating
equipment.
The autoclave moulding can be employed where,
Large contoured, odd shaped parts are moulded.
Preparation of moulds or dies are difficult to make or expensive in construction.
4.2 Method adopted for fabrication
Usually the laminates can be prepared by lay-up techniques. But, the laminates
produced will have voids, cracks and may delaminate easily, applying pressure or
applying vacuum can overcome this. This can be achieved through by bagging the
laminates. This process is called vacuum bagging. A vacuum bag provides both pressure
up to 14.7psi, depending on your altitude and vacuum.
4.3 Accessories
4.3.1 Peel ply
One the laminate is in place; its time to apply the bag the first item to go down is a
peel ply. Peel plies are a tightly woven fabric, often nylon, and impregnated with some
type of release agent. The peel ply will stick to the laminate, but it will pull away without
to much difficulty.
7/28/2019 Composite Project b Tech[1]
30/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 30
Peel ply is optional. Most often it is used to give the laminate a rough, rather than
smooth, finish. Many engineers consider this a bondable finish, and it usually passes a
wet out test.
If peel ply is used, it will absorb a small amount of resin, and this must be
accounted for. A net resin prepared may end up too dry. Peel ply specs should say how
much resin would be absorbed, in ounces per squire foot, or grams per squire meter.
7/28/2019 Composite Project b Tech[1]
31/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 31
Figure 13: Modeling methods and tooling
7/28/2019 Composite Project b Tech[1]
32/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 32
4.3.2 Release film
After the peel ply comes a layer of release film. This is a thin plastic, which has
been treated so it wont bond to the laminate. It is highly stretchable so it can conform to
complex geometries.
Peel ply can be either a solid sheet, or it can have perforations (in the latter case, it
is often called peel ply). The perforations might be like pin pricks, or they might be small
holes, which are punched out. The spacing can also vary from 2 inches to 8 inches.
Choose spacing based on the amount of resin that needs to be bled out: wet lay-ups can
use close spacing; prepared manufactures can recommend spacing for their particular
products; and net resin systems of course use imperforated release films.
Not all release films are compatible with every resin system. a few years ago, they
were preparing some cyan ate-ester test coupons, and the release film we normally used
for epoxies bonded to the coupons. You can also get release film treated so it will bond to
the laminate (bondable one side, bos, or bondable both sides, bbs). Bos can be used to
create a permanent release layer on composites tools, or as a moisture barrier on
laminates.
4.3.3 Bleeder and Breather
At least one layer of bleeder cloth goes above the release film. Bleeder is a thick,
felt like cloth. It purposes is to absorb excess resin. The bleeder also acts as a breather,
providing a continuous air path for pulling the vacuum. If the bag wrinkles agent against
the hard lament, it will trap air. The breather prevents this from happening.
The breather must be thick enough so that it does not become fully saturated with
resin. a thick breather is also desirable to keep resin from coming in contact with the bag.
It does not hurt anything if that happens, but preventing it makes the bag easier to
remove.
7/28/2019 Composite Project b Tech[1]
33/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 33
4.3.4 Bag
The bag is the last item to be placed. Its a relatively thick plastic layer, available
in different amount of conformability. The bag is usually applied along one edge at a
time. Start at one corner and press the bag in to the other corner, removing the release
paper from the tape. As you move along the edge.
Be careful not to get any wrinkles in the bag or it will leak. Plates will be required
for anything but flat or simply curved structures. Make sure you remember to attach the
vacuum port (not shown in the figure) before closing the bag. The base of the port goes
inside the bag; cut a small cross in the bag for the attachment flange to fit through. If the
tool has an area for the port, make sure there is a breather path from the port to the part. If
the port goes on the part itself, put several layers of breather under the port to prevent
print through.
7/28/2019 Composite Project b Tech[1]
34/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 34
CHAPTER-5
EXPERIMENTAL RESULTS
5.1 Introduction to testing
Depending up on the method of load application as a function of time,
mechanical testing can be divided into static, dynamic and fatigue testing. Static and
dynamic are primarily to the study of the extended effects of forces on rigid bodies, i.e.
the bodies for which the change in shape can be neglected.
In static tests, the load on the test specimen is either increased slowly and
progressively or maintained constant for a long time, with the result that the rate of test
piece strain is very low
In dynamics tests, the test piece is subjected to loading at considerable speeds,
so that the rate of strain is high. In case of fatigue tests, the piece is subjected to repeat
loading, which may vary in magnitude only or in magnitude and directions. Mechanical
tests differ also in the methods of load application. Tests in tension, compression,
bending, and torsion etc. are carried out to estimate the mechanical strength or at high or
low temperature, depending on the service conditions of the metals tested.
5.2 Purpose of testing
1) To access the quality of the material in order to prove a competitive marketing for
consumer goods.
2) Evaluate and optimize materials.
3) Evaluate and optimize marketing process variables.
4) To establish engineering design information.
7/28/2019 Composite Project b Tech[1]
35/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 35
Figure 14: Stress- strain diagram
5.3 Test procedure
1. The parameters specified for the compression, tensile inter laminar and flexural
specimens are prepared according to the geometry.
2. Store the specimen in the conditioned environment until test time, if the testing
area environment is different than the conditioning environment.
3. Apply the load to the specimen at the specified rate until failure, while recording
data.
4. Record load verses strain continuously, or at frequent regular intervals.
5. Record the mode and the location of failure of the specimen.
6. Re-examine the means of load introduction in to the material if a significant
fraction of failures in a sample population occur with in one specimen width of the
tab or grip.
5.3.1 Sampling
Test at least 5 specimens per test conditions unless valid results can be gained
through the use of fewer specimens, such as in the case of a design experiment.
7/28/2019 Composite Project b Tech[1]
36/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 36
5.3.2 Labeling
Label the coupons so that they will be distinct from each other and traceable
back to the raw material and in a manner that will both be unaffected by the test and not
influence the test.
5.4 Apparatus
5.4.1 Micrometers
A micrometer with a 4to5mm nominal diameter double-ball interface shall be
used to measure the thickness of the specimen. A micrometer with a flat anvil interface
shall be used to measure the width of the specimen. The accuracy of the instruments shall
be suitable for reading to within 1% of the sample width and thickness.
5.4.2 Testing machine
The testing machine shall be in conformance with practices e4, and shall satisfy
the following.
5.4.2.1 Testing machine heads
The testing machine shall have both an essentially stationary head and a movable
head.
5.4.2.2 Drive mechanism
The testing machine drive mechanism shall be capable of imparting to the
movable head shall be capable of being regulated.
5.4.2.3 Load indicator
The testing machine load-sensing device shall be capable of indicating the total
load being carried by the specimen. This device shall be essentially free from inertia-lag
at the specified rate of testing and shall indicate the load with accuracy over the load
range(s) of interest of within 1% of the indicated value. The load range (s) of interest
may be fairly low for modulus evaluation, much higher for strength evaluation, or both.
7/28/2019 Composite Project b Tech[1]
37/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 37
5.5 Standard test methods for tensile properties of polymer matrix
composite material
ASTM D 3039/D 3039-00
5.5.1 Scope
This test method determines the in-plane tensile properties of polymer matrix
composite materials reinforced by high modulus fibers. The composite material forms
are limited to continuousfiber or discontinuous-fiber reinforced composites in which the
laminate is balanced and symmetric in respect to the test direction.
Figure 15: Standard test specimen details for tensile test
5.5.2 Summary of test method
A thin flat strip of material having a constant rectangular cross-section is mounted
in the grips of a mechanical testing machine and monotonically loaded in tension while
recording load. The ultimate strength of the material can be determined from the
maximum load carried prior to failure. If the coupon strain is monitored with strain or
displacement transducers then the stress-strain response of the material can be
determined, from which the ultimate tensile strain, tensile modulus of elasticity, Poissons
ratio, and transition strain can be derived.
7/28/2019 Composite Project b Tech[1]
38/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 38
5.5.3 Significance and use
This test method is designed to produce tensile property data for material
specifications, research and development, quality assurance, and structural design and
analysis. Factors that influence the tensile response and should therefore be reported
include the following:
Material, methods of material preparation and lay-up, specimen stacking
sequence, specimen preparation, specimen conditioning, environment of testing, time at
temperature. Void content, and volume percent reinforcement properties, in the test
direction, which may be obtained from this test method include the following:
Ultimate tensile strength,
Ultimate tensile strain,
Tensile chord modulus of elasticity,
Poissons ratio, and
Transition strain.
5.5.4 Calculations
The tensile strength of the laminate can be calculated by using the relation,
f=p/bd
Where
f=Tensile strength in N/mm2
p= Max. load in N
b=Breadth of the tensile specimen in mmd=Thickness of the tensile specimen in mm
7/28/2019 Composite Project b Tech[1]
39/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 39
Table 4: Tensile specimen geometry recommendations
Table 5: ASTM standards used for testing the laminates
Fiber
OrientationWidth
mm
Overall
Length
mm
Thickness
mm
Tab
Length
mm
Tab
Thickness
mm
Tab
Bevel
Angle
0
Unidirectional
15 250 1.0 56 1.5 7 or 90
90
Unidirectional
25 175 2.0 25 1.5 90
Balanced and
Symmetric
25 250 2.5 emery
cloth
----- -----
Random
Discontinuous
25 250 2.5 emery
cloth
----- -----
Type of test ASTM designation Length * width Thickness
Range
Tensile
Compressive
Flexural
In-plane shear
Interlaminar shear
d 3039/d 3039-00
d 3410-75
d 790-98
d 4255/d 4255m-83
d 2344-84
250 * 25.0 mm
120 * 12.5 mm
127 *1 2.7 mm
130 * 25.0 mm
020 * 10.0 mm
2-3 mm
2-3 mm
2-3 mm
2-3 mm
2-3 mm
7/28/2019 Composite Project b Tech[1]
40/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 40
5.6 Standard test method for compressive properties of polymer matrix
composite material
ASTM D 3410/D 3410M
5.6.1 Scope
This test method determines the in-plane compressive properties of polymer
matrix composite materials reinforced by high modulus fibers. The composite materials
are limited to continuous fiber or discontinuous fiber re enforced composites in which the
laminate is balanced.
Figure 16: Standard test specimen details for compression test
5.6.2 Summery of test method
A flat strip of material having rectangular cross section is mounted in the grip of
the mechanical testing mission and monotonically loaded in compression while recording
load. The ultimate compressive strength of the material can be determined from the
maximum load carried to failure. If the coupon strain is monitored with strain or
displacement transducers than the stress stain of the response of the material can be
determined, from which the ultimate compressive strain, compressive modulus of
elasticity, Poissons ratio and transition strain can be determined.
7/28/2019 Composite Project b Tech[1]
41/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 41
5.6.3 Significance and use
This test method is designed to produce the compressive property data for material
specification, research and development and quality assurance, and structural design and
analysis. Properties in the test direction, which may be obtained from this test method,
include the following
Ultimate compressive strength
Ultimate compressive strain
Modulus elasticity
Poissons ratio
Transition strain
5.6.4 Geometry
Table 6: Compression specimen geometry recommendations
Design of mechanical test coupons, especially those using end tabs remains to a
large extent. Each major composite testing laboratory has developed gripping methods for
the specific material systems and environments commonly encountered with in that
Fiber
Orientation
Width
mm
Gauge
Length
mm
Tab Length
mm
Overall
Length
mm
Tab
Thickness
mm0
Unidirectional 10 10-25 65 140-155 1.5
90
Unidirectional 25 10-25 65 140-155 1.5
Specially
Orthotropic 25 10-25 65 140-155 1.5
7/28/2019 Composite Project b Tech[1]
42/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 42
laboratory. The compression tensile specimen geometry recommendations are shown in
the following table.
5.6.5 Calculations
The compressive strength of the laminate can be calculated by using the relation
f=p/bd
Where
f=Compressive strength in N/mm2
p= Max. load in N
b=Breadth of the tensile specimen in mm
d=Thickness of the tensile specimen in mm
7/28/2019 Composite Project b Tech[1]
43/88
7/28/2019 Composite Project b Tech[1]
44/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 44
Figure 17: Standard test specimen details for flexural test
5.7.3 Calculations
The flexural strength S of the specimen is given by the formula
S=3pl/2bd2
Where
S=Stress in the outer fires at midspan in N/mm2
p=Load at a given point on the load-displacement curve in N
l=Support span in mm
b=Width of the beam tested in mm.
d=Depth of the specimen in mm.
7/28/2019 Composite Project b Tech[1]
45/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 45
5.8 Standard test method for inter laminar shear properties of polymer
matrix composite material
ASTM D 2344
5.8.1 Scope
This test has been used for determining interlaminar shear strength of bi-
directional laminate specimens. It is believed applicable for any constant temperature at
which the constituent materials are structurally stable. Creep effects are neglected.
Polymeric composites with a laminated and fibrous structure have typical shortcoming in
their low shear resistance, especially in the planes where the properties of the materials
are determined by the matrix (resin). Hence shear strength gives the properties of resin
used.
The ILSS is used to determine the adhesive force at the matrix reinforcement
interface and tangential stresses acting at that interface therefore in the experimental
determination ofILSS, it is important to know the actual magnitude of tangential stresses
which can lead to the failure of the specimen. Because of its simplicity, it is used as a
quality control tool. It involves a three-point flexure specimen with the span to depth ratio
l/h, chosen to produce interlaminar shear failure. A complexity is presented by the short
beam shear method when used for laminated materials.
In particular, the ILSS will be parabolic within each layer, but a discontinuity in
slope will occur at the ply interfaces, as a result the maximum shear stresses will not
necessarily occur at the center. Laminated beam theory is hence required to calculate the
stresses. Thus, the short beam method is applicable only to polymeric and composite
materials, which can be treated as homogenous.
Practical experience showed that interlaminar shear failures are difficult to attain
at higher span to depth ratios. A specimen width maximum thickness of 6.4 mm is
required by ASTM standards. There is no such minimum thickness specified, hence
specimens as thin as 2.9 mm have been used.
7/28/2019 Composite Project b Tech[1]
46/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 46
Figure 18: Standard test specimen details for flexural test
5.8.2 Interlaminar shear strength (ILSS)
The inter facial adhesion between the fiber and matrix resin was measured by
shunt beam there product binding test (ASTM D2344). The width of the specimen was 10
mm and the length was 20-mm. the crosshead speed for the test was 2 mm/min
5.8.3 Procedure
According to ASTM standards D-2344-76 the thickness and width of the
specimen is measured (to nearest 0.025) at the midpoint and the overall length of the
specimen is 20mm and width is 10mm.
The test specimen is placed in the test fixture and aligned so that its midpoint is
centered and long axis is perpendicular to the cylindrical axis or under the loading nose
push the side support into the span previously determined. (10mm). Apply the load to the
specimen at a crosshead rate of 2mm/min.the load to fracture the specimen (maximum
load, displacement on the indicating mechanism) is recoded.
5.8.4 Calculations
The inter laminar shear strength S is calculated by using the formula,
S= (3/4) (w/ab)
S=Inter laminar shear strength in kg/mm2
w=Breaking load in kg
a=Width of the specimen in mm
b= Thickness of specimen in mm
7/28/2019 Composite Project b Tech[1]
47/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 47
BLISS UNIVERSAL TESTING MACHINE
Capacity: 1-50 KN
Figure 19: universal testing machine
FLEXURAL TEST TENSILE TEST COMPRESSION TEST
http://www.instron.in/wa/solutions/solutions_combos.aspx?ParentID=5&ChildID=97http://www.instron.in/wa/solutions/tension_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/flexure_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/solutions_combos.aspx?ParentID=5&ChildID=97http://www.instron.in/wa/solutions/tension_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/flexure_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/solutions_combos.aspx?ParentID=5&ChildID=97http://www.instron.in/wa/solutions/tension_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/flexure_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/solutions_combos.aspx?ParentID=5&ChildID=97http://www.instron.in/wa/solutions/tension_testing_solutions_metals.aspxhttp://www.instron.in/wa/solutions/flexure_testing_solutions_metals.aspx7/28/2019 Composite Project b Tech[1]
48/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 48
CHAPTER-6
RESULTS AND DISCUSSION
6.1 Laminating procedure
1. First the slab was cleaned thoroughly with acetone.
2. Then sealant was put around the required area to be kept under vacuum.
3. Wax was applied within the area enclosed with sealant.
4. The fabric was cut considering the required size and number of layers.
5. The weight of fabric was weighted and noted (wf).
6. The weight of matrix required (wm) was calculated based on the weight of fabric andthe fibre weight fraction.
7. The resin and hardener were mixed appropriately and the time was noted.
8. Teflon mat slightly bigger than the laminate being prepared was put in the area
enclosed with sealant and it was wet a little resin.
9. A single layer of the cut fabric was put on the Teflon mat and wet thoroughly.
10. This process was repeated until the required number of layers was wet (within the geltime of matrix). A Teflon mat was put over the wet layers.
11. Some waste fabric was put on it to absorb the excess resin.
12. This arrangement was covered with a polythene sheet.
13. A breather was put over the polythene sheet and covered with the vacuum bag.
14. Then vacuum was applied just before gelling for two hour.
15. Curing: the laminate was left overnight after removing the vacuum to cure at room
temperature.
16. Post curing: this was done by putting it in an oven at 85oc for two hours.
17. The specimens were cut according to the required size using band saw. Then they
Were ground and polished to the required dimensions. They were stored in airtight
Polythene bags and sent for testing.
7/28/2019 Composite Project b Tech[1]
49/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 49
6.2 Fabrication details of JRP
6.2.1 Specifications of jute reinforced plastics
Materials
Reinforcement fibers: Jute fibers of 1 feet * l feet
Matrix: Resin LY 556 and HardenerHY 951
Process: Hand lay-up and Vacuum bagging at room temperature.
Number of layers: 6 layers of jute fibers.
6.2.2 Reinforcement details of jute reinforced plastics
Thickness of the jute fiber ply = 0.4 mm
No. of jute fibers = 6
Total thickness of the jute fiber ply = 6*0.4 mm
=2.4 mm
Weight of the jute fiber ply = 44 gms
No. of jute fibers = 6
Total weight of the jute fiber ply = 6*44 gms
= 264 gms
For 0.55 weight fraction of jute
The weight of the laminate = 264 gms
7/28/2019 Composite Project b Tech[1]
50/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 50
6.2.3 Stacking sequence of jute reinforced laminate
Figure 20: Stacking sequence of jute reinforced laminate
7/28/2019 Composite Project b Tech[1]
51/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 51
6.2.4 Matrix system details of jute reinforced plastics
For 0.45 weight fraction of matrix system
The weight of the matrix system =0.45*264/0.55
= 216 gms
Weight ratio of resin to hardener =100:12
Weight of the resin only =100*216/112
=193 gms
Weight of the hardener only =12*216/112
=23 gms
6.2.5 Time schedule for jute reinforced plastics
Resin mixed at =10.02 AM
Lay-up started at =10.08 AM
Lay-up completed at =10.40 AM
Vacuum applied (on) at =10.45 AM
Vacuum release (off) at =12.50 AM
7/28/2019 Composite Project b Tech[1]
52/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 52
6.3 Fabrication details of GJRP
6.3.1 Specifications of glass jute reinforced plastics
Material
Reinforcement: Glass cloth E-grade (uni-directional),
Jute fiber of 1 feet* 1 feet
Matrix: Resin LY 556 and HardenerHY 951
Process: Hand lay-up and Vacuum bagging at room temperature.
Number of layers: 5 layers of Glass cloth and 4 layers of Jute cloth.
Mill used: 8 mill
6.3.2 Reinforcement details of hybrid
Thickness of the jute fiber ply = 0.4 mm
No. Of jute fibers = 4
Total thickness of the jute fiber ply = 4*0.4 mm
=1.6 mm
Thickness of the glass fiber ply = 0.17 mm
No. Of glass fibers = 5
Total thickness of the jute fiber ply = 5*0.17 mm
=0.85 mm
7/28/2019 Composite Project b Tech[1]
53/88
7/28/2019 Composite Project b Tech[1]
54/88
Performance of natural @ synthetic fibers reinforced epoxy composites
Page No 54
6.3.4 Weight details of Hybrid
Weight of the jute fiber ply = 44 gms
No. Of jute fibers = 4
Total weight of the jute fiber ply = 4*44 gms
= 176 gms _________ R1
Weight of the glass fiber ply = 13.1 gms
No. Of glass fibers = 5
Total weight of the jute fiber ply = 5*13.1 gms
= 65.5 gms __________R2
Total weight of the reinforcement =R1+R2
=176+65.5
=241.5 gms
For 0.55 weight fraction of (jute+glass)
The weight of the laminate = 241.5 gms
5.3.5 Matrix system details of hybrid
For 0.45 weight fraction of matrix system
The weight of the matrix system =0.45*241.5/0.55
= 197.5 gms
Weight ratio of resin to hardener =100:12
Weight of the resin only =100*197.5/112
=176.5 gms
Weight of the hardener only =12*197.5/112
=21 gms
7/28/2019 Composite Project b Tech[1]
55/88
Performance of natural @ synthetic fibers re
Top Related