This document is a seminar report submitted by Sandeep Kumar on vibration damping characteristics of hybrid polymer matrix composites. It includes an abstract that discusses developing a glass-epoxy composite with added carbon fillers to improve mechanical and damping properties. The report also includes sections on polymer matrix composites, polymer matrix hybrid composites, damping characteristics, materials and methodology used, and results and discussion. Tables of contents and references are also provided.

1. 1
A SEMINAR REPORT ON
VIBRATION DAMPING CHARACTERISTICS OF HYBRIDE
POLYMER MATRIX COMPOSITE
SUBMITTED BY
SANDEEP KUMAR
(ROLL NO.: 1404540044)
IN PARTIAL FULFILLMENT FOR
SEMINAR – IME-654 COURSE
UNDER THE GUIDANCE OF
Shri. JITENDRA BHASKAR
ASSOCIATE PROFESSOR
ME, DEPARTMENT
DEPARTMENT OF MECHANICAL ENGINEERING
HARCOURT BUTLER TECHNICAL UNIVERSITY
KANPUR
MARCH 2017

2. 2
CERTIFICATE
It is certified that Mr. Sandeep Kumar has carried out the seminar on the topic “Dynamic
Characteristics of Polymer Hybrid Matrix Composite” from the Department of
Mechanical Engineering, Harcourt Butler Technical University, Kanpur.
Date: (Jitendra Bhaskar)
Place: Associate Professor
Department of Mechanical Engineering
Harcourt Butler Technical University, Kanpur.

3. 3
ACKNOWLEDGEMENT
First and foremost, I express my deep sense of gratitude and respect to Shri. Jitendra Bhaskar,
Associate Professor, Department of Mechanical Engineering, Harcourt Butler Technical
University, Kanpur for his invaluable comments, teachings and overall support in the
completion of this seminar report.
I am especially indebted to my parents for their love, sacrifice and support. I wish to express
my deep gratitude to all my teachers and colleagues who extended their helping hands
towards me in various ways during compilation of this report. Lastly I acknowledge all the
members of Department of Mechanical Engineering, Harcourt Butler Technical University,
Kanpur.
SANDEEP KUMAR
(Roll No. 1404540044)

4. 4
ABSTRACT
This paper aims to study the damping characteristics of Hybrid polymer composite, which
can be used in many applications and in engineering structures. The investigation aims to
develop glass-epoxy composite with addition of carbon (600mesh) fillers with different
weight fractions and to characterize the mechanical and damping properties. The carbon filler
are used reinforcement and fabricated using Hand lay-up and vacuum bag moulding
technique. The damping characteristics were evaluated using free and forced vibration test
with different amplitudes. The result indicates that the damping characteristics improved with
increase in weight percentage of carbon reinforcement content. Further it was found that glass
fiber-epoxy matrix with 5% carbon particles better damping properties which can be used for
structural application.

5. 5
TABLE OF CONTENTS
TITLE PAGE…………………………………………………………………………1
CERTIFICATE………………………………………………………………………2
ACKNOWLEDGEMENT…………………………………………………………...3
ABSTRACT………………………………………………………………………......4
TABLE OF CONTENTS…………………………………………………………….5
LIST OF FIGURE……………………………………………..……………………..7
1. INTRODUCTION……………………………………………………………………8
1.1 Hybrid Composite 8
1.2 Designing Hybrid Composites 9
2. POLYMER MATRIX COMPOSITE…...………………………………………...10
2.1 Constituents 11
2.1.1 Matrix 10
2.1.2 Thermoset 10
2.1.3 Thermoplastic 12
2.1.4 Reinforcement 13
2.2 Properties 13
2.3 Applications 15
3. POLYMER MATRIX HYBRIDE COMPOSITES……………………….. .........15
3.1 Properties 15
3.1.1 Tensile Strength 15
3.1.2 Yield Strength 16
3.1.3 Peak Load 17
3.1.4 Ductility 17
3.2 Applications 18
4. DAMPING CHARACTERISTICS…………..…………………………………..19
5. MATERIALS AND METHODOLOGY……………..…………………………..21
5.1 Material Used 21
5.2 Fabrication Process 21
5.2.1 Free Vibration Test 21

6. 6
5.2.2 Forced Vibration Test 22
6. RESULT AND DISCUSSION…………………………………………………….23
7. CONCLUSION……………………………………………………………………..24
8. REFERENCES……………………………………………………………………..25

7. 7
LIST OF FIGURES
1. Tri-corner approach in designing of high performance bio composites……………10
2. Thermoset and Thermoplastic…………………………………………………….….12
3. Matrix and Reinforcement sectional view………………………………………..….13
4. Effect of Reinforcements on UTS of the Fibers Reinforced Composites………..…..16
5. Effect of Reinforcements on Yield Strength of the Fibers Reinforced Composites....16
6. Effect of Reinforcements on Peak Load of the Fibers Reinforced Composites…..…17
7. Effect of Reinforcements on Ductility of the Fibers Reinforced Composites…….…18
8. Block diagram for free vibration test…………………………………………….…..22
9. Block diagram for forced vibration test…………………………………………..….23

8. 8
1. INTRODUCTION
1.1 Hybrid Composite
The incorporation of several different types of fibers into a single matrix has led to the
development of hybrid bio composites. The behavior of hybrid composites is a weighed sum
of the individual components in which there is a more favorable balance between the inherent
advantages and disadvantages. Also, using a hybrid composite that contains two or more
types of fiber, the advantages of one type of fiber could complement with what are lacking in
the other. As a consequence, a balance in cost and performance can be achieved through
proper material design [1]. The properties of a hybrid composite mainly depend upon the
fiber content, length of individual fibers, orientation, extent of intermingling of fibers, fiber to
matrix bonding and arrangement of both the fibers. The strength of the hybrid composite is
also dependent on the failure strain of individual fibers. Maximum hybrid results are obtained
when the fibers are highly strain compatible [2]. The properties of the hybrid system
consisting of two components can be predicted by the rule of mixtures.
PH = P1 V1 + P2 V2 [1]
Where, PH is the property to be investigated, P1 the corresponding property of the first
system and P2 the corresponding property of the second system. V1 and V2 are the relative
hybrid volume fractions of the first and second system and
V1 + V2 = 1 [2]
A positive or negative hybrid effect is defined as a positive or negative deviation of a certain
mechanical property from the rule of hybrid mixture.
The term hybrid effect has been used to describe the phenomenon of an apparent synergistic
improvement in the properties of a composite containing two or more types of fiber [3]. The
selection of the components that make up the hybrid composite is determined by the purpose
of hybridization, requirements imposed on the material or the construction being designed.
The problem of selecting the type of compatible fibers and the level of their properties is of
prime importance when designing and producing hybrid composites. The successful use of
hybrid composites is determined by the chemical, mechanical and physical stability of the
fiber / matrix system. There are several types of hybrid composites characterized as:
(1) Interply or tow by tow, in which tows of the two or more constituent types of fiber are
mixed in a regular or random manner;
(2) Sandwich hybrids, also known as core-shell, in which one material is sandwiched
between two layers of another;

9. 9
(3) Interply or laminated, where alternate layers of the two (or more) materials are stacked in
a regular manner;
(4) Intimately mixed hybrids, where the constituent fibers are made to mix as randomly as
possible so that no over-concentration of any one type is present in the material;
(5) Other kinds, such as those reinforced with ribs, pultruded wires and thin veils of fiber or
combinations of the above.
The concept of hybrid systems for improved material or structural performance is well-
known in engineering design. However, it is the inspiration from natures’ own materials that
is recently motivating the path towards innovative material and structural designs. Studies on
natural materials show how high structural performance can be achieved with non-exotic
materials through hybrid combinations assembled in optimized hybrid hierarchical
configurations.
1.2 Designing Hybrid Composites
Although hybrid fiber reinforced polymer composites are gaining interest, the challenge is to
replace conventional glass reinforced plastics with bio-composites that exhibit structural and
functional stability during storage and use and yet are susceptible to environmental
degradation upon disposal. An interesting approach in fabricating bio-composites of superior
and desired properties include efficient and cost effective chemical modification of fiber,
judicious selection if fibers, matrix modification by functionalizing and blending and efficient
processing techniques. (Figure 1)
Another interesting concept is that of “engineered natural fibers” to obtain superior strength
bio composites [3].This concept explores the suitable blending of baste (stem) and leaf fibers.
The judicious selection of blends of bio-fibers is based on the fact that the correct blend
achieves optimum balance in mechanical properties for e.g., the combination of baste and leaf
fiber is expected to provide a stiffness toughness balance in the resulting bio composites

10. 10
Figure:1 Tri-corner approach in designing of high performance bio composites [2]

11. 11
2. POLYMER MATRIX COMPOSITE
Polymer matrix composites (PMCs) are comprised of a variety of short or continuous fibers
bound together by an organic polymer matrix. Unlike a ceramic matrix composite (CMC), in
which the reinforcement is used primarily to improve the fracture toughness, the
reinforcement in a PMC provides high strength and stiffness. The PMC is designed so that
the mechanical loads to which the structure is subjected in service are supported by the
reinforcement. The function of the matrix is to bond the fibers together and to transfer loads
between them.
Polymer matrix composites are often divided into two categories: reinforced plastics, and
“advanced composites.”The distinction is based on the level of mechanical properties
(usually strength and stiffness); however, there is no unambiguous line separating the two.
Reinforced plastics, which are relatively inexpensive, typically consist of polyester resins
reinforced with low-stiffness glass fibers. Advanced composites, which have been in use for
only about 15 years, primarily in the aerospace industry, have superior strength and stiffness,
and are relatively expensive. Advanced composites are the focus of this assessment. Chief
among the advantages of PMCs is their light weight coupled with high stiffness and strength
along the direction of the reinforcement. This combination is the basis of their usefulness in
aircraft, automobiles, and other moving structures. Other desirable properties include superior
corrosion and fatigue resistance compared to metals. Because the matrix decomposes at high
temperatures, however, current PMCs are limited to service temperatures below about 600° F
(316° C).Experience over the past 15 years with advanced composite structures in military
aircraft indicates that reliable PMC structures can be fabricated. However, their high cost
remains a major barrier to more widespread use in commercial applications. Most advanced
PMCs today are fabricated by a laborious process called lay-up.[4]
2.1 CONSTITUENTS
2.1.1 Matrix
The matrix properties determine the resistance of the PMC to most of the degradative
processes that eventually cause failure of the structure. These processes include impact
damage, delamination, water absorption, chemical attack, and high-temperature creep. Thus,
the matrix is typically the weak link in the PMC structure. The matrix phase of commercial
PMCs can be classified as either thermoset or thermoplastic.

12. 12
2.1.2 Thermoset
Thermosetting resins include polyesters, vinylesters, epoxies, bismaleimides, and
polyamides. Thermosetting polyesters are commonly used in fiber-reinforced plastics, and
epoxies make up most of the current market for advanced composites resins. Initially, the
viscosity of these resins is low; however, thermoset resins undergo chemical reactions that
crosslink the polymer chains and thus connect the entire matrix together in a three-
dimensional network. This process is called curing. Thermoses, because of their three-
dimensional crosslinked structure, tend to have high dimensional stability, high-temperature
resistance, and good resistance to solvents. Recently, considerable progress has been made in
improving the toughness and maximum operating temperatures of thermosets.
2.1.3 Thermoplastic
Thermoplastic resins, sometimes called engineering plastics, include some polyesters, poly
etherimide, polyamide imide, poly-phenylene sulfide, polyether-etherketone (PEEK), and
liquid crystal polymers. They consist of long, discrete molecules that melt to a viscous liquid
at the processing temperature, typically 500” to 700” F (260° to 3710 C), and, after forming,
are cooled to an amorphous, semi-crystalline, or crystalline solid. The degree of crystallinity
has a strong effect on the final matrix properties. Unlike the curing process of thermosetting
resins, the processing of thermoplastics is reversible, and, by simply reheating to the process
temperature, the resin can be formed into another shape if desired.Thermoplastics, although
generally inferior to thermoses in high-temperature strength and chemical stability, are more
resistant to cracking and impact damage. However, it should be noted that recently developed
high-performance thermoplastics, such as PEEK, which have a semi-crystalline
microstructure, exhibit excellent high temperature strength and solvent resistance.
Thermoplastics offer great promise for the future from a manufacturing point of view,
because it is easier and faster to heat and cool a material than it is to cure it. This makes
thermoplastic matrices attractive to high-volume industries such as the automotive industry.
Currently, thermoplastics are used primarily with discontinuous fiber reinforcements such as
chopped glass or carbon/graphite. However, there is great potential for high-performance
thermoplastics reinforced with continuous fibers. For example, thermoplastics could be used
in place of epoxies in the composite structure of the next generation of fighter aircraft.

13. 13
Figure:2 Thermoset and Thermoplastic [5]
2.1.4 Reinforcement
The continuous reinforcing fibers of advanced composites are responsible for their high
strength and stiffness. The most important fibers in current use are glass, graphite, and
aramid. Other organic fibers, such as oriented polyethylene, are also becoming important.
PMCs contain about 60 percent reinforcing fiber by volume. The strength and stiffness of
some continuous fiber reinforced PMCs are compared with those of sheet molding compound
and various metals in figure 3. For instance, unidirectional, high- strength graphite/epoxy has
over three times the specific strength and stiffness (specific properties are ordinary properties
divided by density) of common metal alloys. Of the continuous fibers, glass has a relatively
low stiffness; however, its tensile strength is competitive with the other fibers and its cost is
dramatically lower. This combination of properties is likely to ensure that glass fibers remain
the most widely used reinforcement for high-volume commercial PMC applications. Only
when stiffness or weights are at a premium would aramid and graphite fibers be used.
Figure:3 Matrix and Reinforcement sectional view [6]

14. 14
2.2 PROPERTIES
The properties of the PMC depend on the matrix, the reinforcement, and the interphase.
Consequently, there are many variables to consider when designing a PMC. These include
not only the types of matrix and reinforcement but also their relative proportions, the
geometry of the reinforcement, and the nature of the interphase. Each of these variables must
be carefully controlled to produce a structural material optimized for the conditions for which
it is to be used. The use of continuous-fiber reinforcement confers a directional character,
called an isotropy, to the properties of PMCs. PMCs are strongest when stressed parallel to
the direction of the fibers (0°,axial, or longitudinal, direction) and weakest when stressed
perpendicular to the fibers (90°, transverse direction). In practice, most structures are
subjected to complex loads, necessitating the use of fibers oriented in several directions (e.g.,
0, ±45, 90°). However, PMCs are most efficiently used in applications that can take
advantage of the inherent anisotropy of the materials. When discontinuous fibers or particles
are used for reinforcement, the properties tend to be more isotropic because these
reinforcements tend to be randomly oriented, Such PMCs lack the outstanding strength of
continuous-fiber PMCs, but they can be produced more cheaply, using the technologies
developed for unreinforced plastics such as extrusion, injection molding, and compression
molding. Sheet molding compound (SMC) is such a material, widely used in the automotive
industry; see figure 3-3. The complexity of advanced composites can complicate a
comparison of properties with conventional materials. Properties such as specific strength are
relatively easy to compare, advanced composites have higher specific strengths and stiffness
than metals, as shown in figure 3-3. In many cases, however, properties that are easily
defined in metals are less easily defined in advanced composites. Toughness is such a
property. In metals, wherein the dynamics of crack propagation and failure are relatively well
understood, toughness can be defined relatively easily. In an advanced composite, however,
toughness is a complicated function of the matrix, fiber, and interphase, as well as the
reinforcement geometry. Shear and compression properties of advanced composites are also
poorly defined. Another result of the complexity of PMCs is that the mechanical properties
are highly interdependent. For instance, cracking associated with shear stresses may result in
a loss of stiffness. Impact damage can seriously reduce the compressive strength of PMCs.
Compressive and shear properties can be seen to relate strongly to the toughness of the
matrix, and to the strength of the interfacial bond between matrix and fiber.[7]

15. 15
2.3 APPLICATIONS
PMCs are more mature technology than structural ceramics. With the experience gained in
military applications such as fighter aircraft and rocket motor casings beginning in the 1970s,
advanced composites now have a good record of performance and reliability. They are
rapidly becoming the baseline structural material of the defense/aerospace industry. Because
of their high cost, diffusion of advanced composites into the civilian economy is likely to be a
top-down process, progressing from relatively high value-added applications such as aircraft
to automobiles and then to the relatively low-technology applications such as construction,
which generally requires standardized shapes such as tubes, bars, beams, etc. On the other
hand, there is also a bottom-up process at work in which savings in manufacturing costs
permit unreinforced engineering plastics and short fiber-reinforced PMCs to replace metals in
applications in which high strength and stiffness are not required, such as use of SMC for
automobile body panels

16. 16
3. HYBRID POLYMER MATRIX COMPOSITE
3.1 Properties
3.1.1 Tensile Strength
The effect of reinforcement on Ultimate Tensile Strength (UTS) of the fiber reinforced
composites. The ultimate tensile strength of the carbon reinforced composite was higher as
compared to other type of composites. The 60% carbon fiber reinforced composites shows
65.24% increase in the UTS as compared to 60% glass fiber reinforced composites and
38.01% increase in the UTS with that of 30% glass fiber and 30% carbon reinforced hybrid
composite. The UTS of carbon fiber reinforced composite is higher because the strength of
carbon fiber is higher and it behaves like elastic material during tensile loading. The inclusion
of carbon fiber mat reinforced polymeric composite significantly enhanced the ultimate
tensile strength of the composite.
Figure:4 Effect of Reinforcements on UTS of the Fibers Reinforced Composites [8]
3.1.2 Yield Strength
The yield strength of the glass fiber and carbon fiber reinforced epoxy composites depends
upon the strength and modulus of the fibers, strength, and chemical stability of the matrix,
fiber matrix interaction, and fiber length. The 60% carbon fiber reinforced composites shows
61.31% increase in the yield strength as compared to 60% glass fiber reinforced composites
and 30% increase in the yield strength with that of 30% glass fiber and 30% carbon
reinforced hybrid composite. Figure shows the effect of reinforcements on yield strength of
the fibers reinforced composites. Yield strength increases with increase in addition of
reinforcement to composites this may be due to improved in interfacial bonding strength
between filler, matrix, and fiber.

17. 17
Figure 5: Effect of Reinforcements on Yield Strength of the Fibers Reinforced Composites[8]
3.1.3 Peak Load
The effect of reinforcements on peak load of the fibers reinforced hybrid composites. The
60% carbon fiber reinforced composites shows 68.52% increase in the peak load withstand
capability as compared to 60% glass fiber reinforced composites and 35% increase in the
peak load withstand capability with that of 30% glass fiber and 30% carbon reinforced hybrid
composite. The hybrid composite shows more peak load withstand capability as the carbon
fiber reinforcement percentage increases in the hybrid composite.
Figure 6: Effect of Reinforcements on Peak Load of the Fibers Reinforced Composites [8]
3.1.4 Ductility
The variation of ductility of fiber reinforced composites is shown in Figure 5. The ductility of
30% glass fiber and 30% carbon reinforced hybrid composite is lower as compared to other
two composites. The 60% carbon fiber reinforced composites shows 26.19% increase in the

18. 18
ductility as compared to 60% glass fiber reinforced composites and 50.94% increase in the
ductility with that of 30% glass fiber and 30% carbon reinforced hybrid composite.
Figure 7: Effect of reinforcements on ductility of the fibers reinforced composites [9]
3.2 APPLICATIONS
The natural fiber-reinforced composites have been used for various applications and for
replacing the existing higher weight materials. The composite solid cones were developed
using the oil palm/coir fiber-reinforced hybrid composites. The low-cost hybrid bio-fiber
based composites for structural cellular plates were fabricated for structural applications. The
glass/jute fiber-reinforced pipe bend was fabricated by Cicala etal. with a cost reduction of
20% and a weight reduction of 23% when hemp mat have been used compared to commercial
pipe construction.[10]
The important applications are:-
 Building and construction industry: panels for partition and false ceiling, partition
boards, wall, floor, window and door frames, roof tiles etc.
 Storage devices: post-boxes, grain storage silos, biogas containers, etc.
 Furniture: chair, table, shower, bath units, etc.
 Electric devices: electrical appliances, pipes, etc.
 Everyday applications: lampshades, suitcases, helmets, etc.
 Transportation: automobile and railway coach interior, boat, gears etc.

19. 19
4. DAMPING CHARACTERISTICS
Vibrations are undesirable for structural, owing to the need for structural stability, position
control, durability (particularly against fatigue). Performance and noise reduction .Vibration
are of concern to large structures such as air craft, as well as small structures such as
electronics, vibration reduction can be attained by increasing the damping capacity (loss of
energy) and/or increasing the stiffness (storage modulus). The loss modulus is the product of
these two quantities and thus can be considered a figure of merit for the vibration reduction.
Damping of a structure can be attained by passive or active methods. Passive methods make
use of the inherent ability of certain materials (whether structural or non-structural material)
to absorb the vibration energy, Thereby providing passive energy dissipation. Active methods
make use of sensor and actuators to attain vibration sensing and activation to suppress the
vibration in a real time, the sensors and actuators can be piezoelectric devices. Materials for
vibration damping are mainly 1.metals, 2.polymers and rubber because of their viscoelastic
character. Rubber is commonly used as a vibration damping material owing to its
viscoelastic. However Viscoelastic is not only mechanism for damping. Defects such as
dislocation, phase boundaries, grain boundaries and various interfaces also contribute to
damping, since defects may move slightly and surfaces may slip with respect to one another
during vibration, Thereby dissipating energy. Thus, The microstructure greatly affects the
damping capacity of the material. The damping capacity depends not only on the material,
but also on the loading frequency, as the viscoelasticity as well as defects response depends
on the frequency. The damping capacity also defends on the temperature. Owing to the
interface between reinforced (particles, whiskers or fibers) and matrix in a composite,
Composite formation tends to increase the damping capacity, in addition to the well-known
effects of increasing the stiffness. A high stiffness is useful for vibration reduction. However,
metal matrix composites are expensive to make and their competition with the high damping
alloy is difficult, a particular common form of composite is a laminate in which a high
damping layer is sandwiched and constrained by stiff layers. The shear deformation of the
constrained layer provides damping, while the stiff layer allows structural use of
the laminate. Polymers for vibration damping are Due to their Viscoelastic behavior,
polymers (particularly thermoplastic) can provide damping. Rubber is particularly well
known for its damping ability. However, rubber suffers from low
stiffness, which results in a rather low value of the loss modulus; other polymers used for
vibration damping include polyurethane.[11] The common Viscoelastic materials are:-

20. 20
 Acrylic rubber
 Polypropylene/butyl rubber blend
 Polyvinyl chloride/chlorinated
 Polyethylene/ epoxidized natural rubber blend
 Polyimide / Polyimide blend
 Polysulfide / Polysulfide blend
 Nylon-6/polypropylene blend
 Fluor silicon rubber
 Nits rile rubber
 Silicon rubber
In General purpose of viscoelastic materials are used for low amplitude vibration damping,
such as sound transmission and acoustical wave thought elastic media. Industrial uses of
rubber products Isolation systems, automobile tires, bushing, mounts, seals, diaphragm,
rubber pads, lubricants, speakers, machinery pads, electronic devices etc. In automobile
engines and pump applications, bearing are very important to maintain smooth transmission
of motion and enables noiseless operation. In general babbit metal, bronze, cast iron, gun
metal and non-metals such as carbon, graphite and rubber are used for the construction of
bearing. In recent development of material science polymer and ceramic composites are
considered the most practical and light weight structural materials in the composite
industries. Compared with conventional metal bearing with polymer and ceramic bearing
have been shown to offer significant benefits in terms of rolling contact fatigue life, and the
low density of material greatly reduce the dynamic loading in very high speed applications
such as machine tools and aircraft and gas turbine engines. The technological developments
in composite materials are responsible for partially meeting the global industrial demand for
materials with improved performance capabilities. Polymer composites are used mainly in
automobile and aircraft industries applications. Polymer matric are generally thermosets and
thermoplastics polymers are being used as matrices. Unsaturated polyesters resins have been
in use for decades in production of many industrial applications. For heavy duty structural
applications epoxides, phenolic, and a few specialty polymer materials are used on a
commercial scale. Polymers such as PEEK, PSUL, polyesters, vinyl ester, epoxies,
polyamides etc. These polymers are used in many combinations in different fibers for
developing the bearing materials with high wear resistance and less coefficient of
friction.[12]

21. 21
5. MATERIALS AND METHODOLOGY
5.1 Material Used
The following materials such as Glass fiber, epoxy resin and carbon particles are used. The
E-glass chopped mat fabric of 0.4mm and epoxy resin (LY 556) with room temperature
curing hardener (HY 951 grade) with diluent DY 021 mix was employed for the matrix
material. The carbon particle [600_mesh] materials are used in the Glass and carbon-epoxy
composite.
5.2 Fabrication Process
The fabrication process is done by vacuum bag molding. The vacuum bag molding is
modification to the wet hand layup technique. The circular mold is prepared as per required
beam dimensions (300mm x25mmx4.5mm). The Glass-epoxy material and carbon particles
with different volume fractions is mixed and stirred manually. The mixed materials are
poured into the prepared mold. The mold is placed inside the bag made of flexible film and
all edges are sealed. The bag is then evacuated, so that pressure eliminates voids in the
laminate, forcing excess air and resin from the mold. The laminate is then placed in the oven
with 100°c temperature and kept for 1hour for curing completely. The cutting operation is
done for cutting the laminate into dimensions required for the test such as Free and Forced
vibration by using LABVIEW software
5.2.1 Free vibration test
The system was displaced from its mean position and released .the resulting free vibrations
are recorded. From which information regarding the natural frequency and damping can be
obtained, In practice, a mechanical system under test is rapped by impact from a light
hammer to include free vibrations.

22. 22
Figure:8 Block diagram for free vibration test [13]
5.2.2 Forced vibration test
External forces using by mini shaker. The system was displaced from its mean position and
released .the resulting free vibrations are recorded. From which information regarding the
natural frequency and damping can be obtained, In practice, a mechanical system under test is
rapped by impact from a light hammer to include free vibrations.
Figure:9 Block diagram for forced vibration test [14]

23. 23
6. RESULT AND DISCUSSION
6.1 Natural Frequency:
The density of the GFRP beam is about 1.98 g/cm3 is much lesser than the density of the
glass fiber. Therefore, the natural frequencies of the GFRP with carbon beams are decreased
accordingly due to the increase of the overall density of the beams. However, this
phenomenon can be changed by using composite materials with high tensile modulus. The
natural frequencies of the composite beams with different volume of fiber hat the natural
frequencies initially decrease for the beam with different volume fraction. The decrease of the
natural. The frequencies are then increased with continuously increasing the damping
ratio.
6.2 Damping property
The damping property of the beam is tested by free and forced vibration test then comparing
results, And Different compositions shows the free vibration of the GFRP beam and natural
frequency. The Settling time decreases due to the increase in force generated by the hybrid
composite beam

24. 24
7. CONCLUSIONS
The carbon fiber and glass fiber reinforced hybrid composites have been fabricated by
vacuum bag method. Experimental evaluation of mechanical properties like micro hardness,
tensile and flexural strength of hybrid composites as per ASTM standards has been
successfully completed. The micro hardness of carbon fiber reinforced composite is higher
than the other composites. The tensile properties have been studied and the breaking load has
been measured. The inclusion of carbon fiber mat reinforced polymeric composite
significantly enhanced the ultimate tensile strength, yield strength and peak load of the
composite. The ductility of carbon fiber reinforced composite is higher than the other
composites.

25. 25
8. REFRENCES
1. Amar Patnaik and Mahapatra S S(2009), “Study on Mechanical and Erosion W ear
Behavior of Hybrid Composites Using Taguchi Experimental Design”, J. Materials
and Design,Vol. 30, pp. 2791-2801.
2. Chauhan S, Kumar A, Patnaik A, Satapathy A and Singh I (2009), “Mechanical and
Wear Characterization of GF Reinforced Vinyl Ester Resin Composites with Different
Co-monomers”, J. Reinf. Plast. Compos.,Vol. 28, pp. 2675-2684.
3. Folkes M J (1992), “Multi Component Polymer Systems”, in Miles I S and Rostami S
(Eds.), Longman Scientific and Technical: Essex, Chapter 8, UK.
4. Gururaja M N and Hari Rao A N (2012), “A Review on Recent Applications and
Future Prospectus of Hybrid Composites”, International Journal of Soft Computing
and Engineering (IJSCE), Vol. 1, No. 6, pp. 352-355.
5. Manders P W and Bader M G (1981), “The Strength of Hybrid Glass/Carbon Fibre
Composites: Part 1 Failure Strain Enhancement and Failure Mode”, Journal of
Materials Science, Vol. 16, pp. 2233-2245.
6. Marom G, Fischer S, Tuler F R and Wagner H D (1978), “Hybrid Effects in
Composites: Conditions for Positive or Negative Effects versus Rule-of-Mixtures
Behavior”,Journal of Materials Science,Vol. 13, pp. 1419-1426
7. Prabhakaran R T D, Madsen B,Toftegaard H and Markussen C M (2012),“Flexural
Properties of Hybrid Natural Composite-Micromechanics and Experimental
Assessment”, Proceedings of 3 Asian Conference on Mechanics of Functional
Materials and Structures (ACMFMS), Vol. 1, pp. 469-472, Indian Institute of
Technology, New Delhi.
8. Manex Martinez-Agirre, Maria Jesus Elejabarrieta. Dynamic characterization of high
damping Viscoelastic materials from vibration test data. Journal of Sound and
Vibration, Vol. 330, 2011, PP. 3930–3943
9. B.Darabi, J.A.Rongong. Polymeric particle dampers under steady-state vertical
vibrations. Journal of Sound and Vibration, Vol. 331, 2012, PP. 3304–3316.
10. Y.Hong, X.D.He, R.G.Wang. Vibration and damping analysis of a composite
blade.Material and design, Vol. 34, 2012, pp. 98-105
11. Chensong Dong, Ian J.Davies. Optimal design for the flexural behavior of glass and
carbon fiber reinforced polymer hybrid composites. Materials and Design, Vol. 37,
2012, pp. 450–457
12. Chensong Dong, Heshan A. Flexural properties of hybrid composite reinforced by S-
2glass and T700S carbon fibers Composites. Composites Part B, Vol. 43, 2012,
pp.573–581.
13. Yuvaraja.M, Senthilkumar.M. Comparative study on vibration characteristics of a
flexible GFRP composite beam using SMA and PZT Actuators, Manuf. and Ind.
Engg, Vol. 11(1), 2012, pp. 1338-6549.
14. Yuvaraja.M, Senthilkumar.M, I.Balaguru.Study on vibration characteristics of PZT
Actuated mild steel and aluminum cantilever beams. International journal of
engineering, Vol. 1, 2011, pp. 1584-2673