effect of natural sisal fiber reinforcement on the ... test composite as well as the using natural...
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International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:01 30
N SI J E IJENS February 2017IJENS © -IJMME-4848-170601
Effect of Natural Sisal Fiber Reinforcement on the
Composite Plate Buckling Behavior Muhannad Al-Waily, Alaa Abdulzahra Deli, Aziz Darweesh Al-Mawash, Zaman Abud Almalik Abud Ali
Abstract— Buckling behavior of composite plate taking into
account the effect of natural sisal fiber reinforcement is
presented in this work. Investigating the buckling load of
composite plate was done using both experimental and
theoretical (including analytical and numerical) techniques. The
composite plate specimens examined was reinforced with various
volume fractions of natural sisal fiber. Furthermore, the
composite plate was supported with different boundary
conditions. The experimental and analytical data obtained for the
buckling load are further supported with numerical data
evaluated using the finite element method by ANSYS 14.0
commercial code. In the experimental method, the samples of the
tensile test composite as well as the buckling plate are firstly
manufactured. Then, the modulus of elasticity for the samples of
composite plate with tensile test was evaluated, while the
buckling load of plate was evaluated by the buckling test of
composite plate. The results of buckling plate reveal that the
reinforcement of natural sisal fibers leads to increasing the plate
stiffness, and hence, causes an increase in the buckling load of
composite plate. Moreover, a comparison was conducted between
the data obtained for the buckling load, where a good agreement
was found. The maximum error found between the results
obtained experimentally and those estimated theoretically was
about (12.28%), while it was about (3.9%) between the analytical
and numerical predictions.
Index Term-- Buckling Plate, Sisal Fiber Reinforcement,
ANSYS Program Buckling, experimental buckling, composite
plate buckling, composite material plate, composite buckling.
I. INTRODUCTION
Natural fibers are usually classified as plant, animal and
mineral fibers. The plant fibers include many types, which are
seed fiber, stalk fiber, Leaf fiber, fruit fiber, stem and Tracheid
(Wood (Softwood & Hardwood)). The natural fibers have a
significant role in the industry field and contribute
considerably in reducing the production cost, especially the
consumables, [1].
When fibers obtained from plant origin or some other living
species, i.e. natural fibers, are used as reinforcement in
polymer composites, then it is called natural fiber polymer
composite.
Muhannad Al-Waily University of Kufa, Faculty of Engineering, Mechanical Engineering
department, Iraq, [email protected]
Alaa Abdulzahra Deli University of Kufa, Faculty of Engineering, Mechanical Engineering
department, Iraq, [email protected]
Aziz Darweesh Al-Mawash University of Kufa, Faculty of Engineering, Mechanical Engineering
department, Iraq, [email protected]
Zaman Abud Almalik Abud Ali University of Kufa, Faculty of Engineering, Mechanical Engineering
department, Iraq, [email protected]
The major factors affecting the structure as well as chemical
composition of plant fibers are the environmental conditions
and its age. The primary ingredient of any plant fiber is water.
However, if considered on dry basis, all natural fibers consist
of cellulose and hemicellulose combined with lignin along
with small amount of starch, proteins and other extractives
which are distributed all over the cell wall.
The effect of sisal reinforcement fiber on composite plate
behavior has gained increasing interest recently. An
experimental and numerical study was presented by Zaman
[2] regarding the preparation of composite material specimen
using natural fibers sisal and polyester resin. The specimens
were pretreated in different volume fractions of sisal and
resins, which were (5-35) % sisal. Specimen model was
fabricated in a plate shape, where vibration and tensile tests
were applied. Natural frequency was obtained through
numerical analysis using ANSYS 14.0 commercial code. A
similarity was observed between the experimental and
numerical data obtained. The findings obtained reveal that
increasing the volume fraction of sisal fibers results in
improving the dynamic behavior of the plate tested. The
mechanical and thermal properties of composite materials
with silica reinforcement effect were examined by Gowthami
et al. [3]. The mechanical properties studied were the strength
and modulus of elasticity of composite materials with silica
reinforcement. In addition, influence of thermal properties of
composite materials, taking silica effect into account, was
studied, e.g. specific heat. It was also shown that using silica
reinforcement in the composite materials improves the
mechanical properties significantly. The impact of fiber
orientation on mechanical properties of sisal fiber reinforced
composites was experimentally studied by Kumaresan et al.
[4]. Sisal fiber was used as a reinforcement, which is treated
with NaOH solution to enhance the bonding strength between
fiber and resin. Samples having various orientations of sisal
fiber were firstly fabricated by compression molding, and then
their mechanical properties, i.e. tensile strength and flexural
strength, were investigated. Romildo et al. [5] presented a
study for the effect of sisal fiber reinforcement on the tensile,
compression, and bending behaviors in addition to the creep
and other properties of composite materials. It was noticed
that the sisal fiber reinforcement improves the properties of
composite materials; hence, sisal fiber reinforcement
composite materials can be utilized efficiently in civil
construction. Kumar et al. [6] conducted an experimental
vibration analysis of composite laminate taking into account
the effect of different natural reinforcement fiber. The
reinforcement natural fibers tested were the short sisal and
banana reinforcement fibers. The composite materials
examined was combined form random short reinforcement
International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:01 31
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sisal or banana fiber and polyester resin materials. The results
concluded indicate that the mechanical properties and
vibration of composite laminate is improved with increasing
the reinforcement of natural fibers. Oladele et al [7]
investigated the effects of production processes on the
mechanical properties of sisal fiber reinforced polypropylene
(PP) composites. The sisal fiber used for the reinforcement
was extracted by soil retting, and then chemically treated.
Both treated and untreated sisal fiber were characterized and
used for the reinforcement of homopolymer and copolymer
polypropylene. The composites were produced by
compression molding technique after which mechanical tests
such as tensile, impact and hardness tests were carried out on
the samples. The results showed that soil retting is efficient for
the extraction of sisal fiber and that chemical treatment can be
used to enhance the properties of the fiber as well as the
mechanical properties of the composites produced.
The above mentioned researches examined thoroughly the
mechanical properties and vibration behavior of sisal
reinforcement effect. However, the impact of sisal fiber
reinforcement on the buckling behavior of composite
structures has not been investigated before. Thus, the current
work aims to experimentally and numerically study the
influence of sisal reinforcement on the buckling behavior of
composite plate with different supports. It is also aimed to
investigate the buckling load analytically for simply supported
plate with sisal reinforcement. Also, the mechanical properties
of composite materials plate is planned to be studied
analytically and experimentally.
II. EXPERIMENTAL INVESTIGATION
The experimental study includes estimation of the mechanical
properties of composite materials that consist of polyester
resin materials, which is reinforced with sisal natural fiber.
Then, the buckling load of composite plate is measured for
various sisal volume fractions and boundary conditions. The
manufacture of composite tensile test sample and buckling
plate sample includes mixing the polyester resin materials
with the sisal natural fiber inside mineral mold. Later, pressure
is applied on the samples using hydraulic jack, as illustrated in
Fig. 1. The mechanical properties of composite materials is
determined for five samples of fiber volume fractions as
shown in Figs. 2 and 3 for longitudinal and transverse
directions; so, the mechanical properties for each volume
fraction is evaluated for five samples depending on the
average value for each ratio as in Fig. 4.
The samples used in tensile test of orthotropic composite
materials, are shown in Figs. (5-a) & (5-b) for longitudinal and
transverse directions, are taken from the ASTM (D 3039 M-
E122) [8]. The tensile test is accomplished using the universal
machine to get results illustrated in Fig. 6.
The five tensile samples for each volume fraction are
evaluated by dividing the sample made for each volume
fraction with dimensions detailed below, as given in Fig. 7:
1. The length of composite tensile sample .
2. The width of composite tensile sample .
3. The thickness of composite tensile sample .
Fig. 1. Block to manufacture the composite plate structure.
Fig. 2. Modulus of elasticity in longitudinal direction of composite materials.
Fig. 3. Modulus of elasticity in transverse direction of composite materials.
Fig. 4. Experimental Modulus of Elasticity for Different Sisal Volume
Fraction Reinforcement of composite Materials.
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a. Longitudinal direction fiber.
b. Transverse direction fiber.
Fig. 5. Longitudinal and transverse tensile test samples.
Fig. 6. Universal tensile test machine.
The weight required for tensile sample for each volume
fraction are shown in Table I, which are calculated as,
(1)
Where
, [2], and
are volume fractions of sisal fiber and
polyester resin materials, respectively.
Moreover, the tensile sample is divided into five tensile test
samples with the dimensions below, [9, 10]:
1. The length of composite tensile sample .
2. The width of composite tensile sample .
3. The thickness of composite tensile sample .
(a) Longitudinal tensile samples.
(b) Transverse tensile samples.
Fig. 7. Divided of longitudinal and transverse tensile samples.
Longitudinal tensile plate sample
𝑆𝑙1
𝑆𝑙2
𝑆𝑙3
𝑆𝑙4
𝑆𝑙5
Fiber direction
𝑆𝑡1
𝑆𝑡2
𝑆𝑡3
𝑆𝑡4
𝑆𝑡5
Transverse tensile plate sample
Fiber direction
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Table I
Required weight for sisal and polyester resin of tensile test composite sample
Sample (%)
(%)
Weight of
fiber (g)
Weight of
resin (g)
1 0 100 0 220
2 10 90 28 198
3 20 80 56 176
4 30 70 84 154
5 40 60 112 132
In the second part of experimental work, the sample's buckling
load of composite plate were evaluated, as seen in the Fig. 8,
for different fiber volume fractions with two boundary
conditions as:
1. Two edges free and other two edges fixed supported
(CCFF).
2. Two edges free and other two edges simply supported
(SSFF).
The dimensions of composite plate sample are,
1. The length of composite plate sample .
2. The width of composite plate sample .
3. The thickness of composite plate sample .
Also, the weight of fiber reinforcement and polyester resin
materials required to made buckling plate sample are shown in
Table II, where the required weight can be calculated as,
(2)
Table II
Required weight for sisal and polyester of vibration plate composite samples
Sample (%)
(%)
Weight of
fiber (g)
Weight of
resin (g)
1 0 100 0 132
2 10 90 16.8 118.8
3 20 80 33.6 105.6
4 30 70 50.4 92.4
5 40 60 67.2 79.2
Fig. 8. Vibration sample of composite plate with sisal reinforcement.
The buckling load of each volume fraction ratio is evaluated
for four samples, as shown in Figs. 9 and 10, and then, the
average value of each samples is estimated, as explained in
Fig. 11 for various boundary conditions as,
1. Simply supported for two edges (at sides) and free
supported for other two edges (at sides) (SSFF), Fig.
12.a.
2. Clamped supported for two edges (at sides) and free
supported for other two edges (at sides) (CCFF), Fig.
12.b.
Another measurement of the buckling load was done by
conducting compression between the composite plate samples
after supporting the plate in the universal tensile machine with
compression parte, as displayed in Fig. 13. Then, the lateral
displacement of composite plate is recorded depending on the
(dial gauge) from both sides, surrounding the value of
buckling load when the (dial gauge) begins to read the
deflection of composite plate, as demonstrated in Fig. 14.
Alternatively, the buckling load can be measured by locating
the point where the compression curve changes from linear to
another trend, which is known as the buckling load, [11], as
indicated in Fig. 15.
Later on, from Figs. 4 and 11, it can be observed that
increasing the sisal reinforcement causes an enhancement in
the composite materials strength and modulus of elasticity in
directions 1 and 2. Therefore, increasing the sisal
reinforcement augments the buckling load of composite plate
with CCFF and SSFF supported plate. Also, Fig. 11, shows
that the buckling load of CCFF supported plated is more than
it is for the SSFF supported plate since the stiffness of the
latest is greater than the stiffness of the SSFF supported
composite plate.
Fig 9. Experimental buckling load for four samples of each volume fraction of
sisal reinforcement for SSFF plate boundary.
Fig. 10. Experimental buckling load for four samples of each volume fraction
of sisal reinforcement for CCFF plate boundary.
𝑤𝑏
𝑙𝑏
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Fig. 11. Experimental buckling load for different sisal volume fraction and
various boundary condition of composite plate.
(a) SSFF plate supported.
(b) CCFF plate supported.
Fig. 12. Supported of composite plate samples.
Fig. 13. Buckling load machine.
Fig. 14. Buckling plate sample.
Fig. 15. Compression load- displacement relation.
III. ANALYTICAL INVESTIGATION
The analytical part of the present work includes evaluating the
mechanical properties and critical buckling load of simply
supported plate with different fiber volume fractions. Also, the
theoretical results were compared with the numerically
computed data, where an excellent good agreement was found.
The results obtained analytically for the modulus of elasticity
were also compared with the experimentally measured data.
The equation can be used to evaluate the critical buckling load
for orthotropic composite plate is [12],
( )
(1)
Where w is the deflection of plate in z-direction.
Then, by solving Eq. 1 for simply supported plate with
substituting
(for are length and
width of plate, respectively) into Eq. 1, and then using
orthogonally method; a general equation for the buckling load
(N/m) of simply supported plate is derived as,
2√ 11 22
2[√
11
22(
)
( 12 66)
√ 11 22 √
22
11( 2
)
]
(2)
𝑤𝑏
𝑙𝑏
𝑆 𝑆
𝐹
𝐹
𝑤𝑏
𝑙𝑏
𝐶 𝐶
𝐹
𝐹
Output read load
Composite buckling
plate sample
Dial gage
Move supported
Buck
lin
g p
late
D
ial
gage
Sup
po
rted
of
pla
te p
arts
International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:01 35
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Where 1
3
( 12 21) ,
2 3
( 12 21) ,
2
3
( 12 21) ,
12 3
While are the moduli of elasticity of composite
plate in 1 and 2-direction, respectively. Also, is the
Passion’s ratio of composite plate in 1,2-direction, stands
for the modulus of rigidity in 1,2-direction of plate, and h
represents the thickness of plate (can be used ).
Apparently, the above equation requires the mechanical
properties of the composite material investigated. Therefore,
the mechanical properties for both the sisal reinforcement
fiber and polyester resin materials are evaluated provided
separately, i.e. modulus of elasticity, modulus of rigidity, and
Poisson’s ratio. Thus, the Poisson's ratio and modulus of
elasticity for sisal fibers are respectively , [7], while the corresponding values for the resin
polyester are , [8], respectively.
Eventually, the modulus of rigidity for sisal and polyester
materials can be evaluated as,
( ) , so,
, (3)
Where, G: shear modulus, E: Modulus elasticity, ν: Poisson
ratio; while the Poisson ratio of composite material specimen
can be found using the equation below [9],
(4)
Where, : Volume fraction of fibres, : Poison’s
ratio of fibres, : Volume fraction of polyester, and
: Poisson’s ratio of polyester
The shear modulus of composite material can be found using
equation below: [9],
(5)
Also, the modulus of elasticity in longitudinal and transverse
directions can be evaluated by, [13],
( ) (6)
Thus, the theoretically calculated mechanical properties of
composite materials required for evaluating the buckling load
of simply supported composite plate using equation Eq. 2 are
listed in Table III.
Table III
Theoretical input data of mechanical properties required.
Sample ( )
( )
( )
1 100 0 4 4 1.43 0.4
2 90 10 4.65 4.26 1.53 0.392
3 80 20 5.3 4.57 1.64 0.384
4 70 30 5.95 4.91 1.77 0.376
5 60 40 6.6 5.32 1.92 0.368
Then, the experimentally estimated mechanical properties
given in Fig. 4 were compared with the theoretical data
presented in table 3, as illustrated in Figs. 16 and 17 where a
good agreement has been observed with maximum error about
(9.8%).
The analytical solution derived for the simply supported
composite plate (compound of the unidirectional fiber and
resin materials) using the general equation of buckling load,
i.e. Eq. 2. The analytical data obtained from this equation are
illustrated in Fig. 18 for the relation between the buckling load
and sisal reinforcement volume fraction. It is clear that the
buckling load is enhanced with increasing the fiber sisal due to
augmentation in the modulus of elasticity of composite
materials. Also, it is noticed that the buckling load of simply
supported plate is more than it is for other supported plates
presented in the experimental work.
Fig. 16. Comparison between experimental and theoretical work for modulus
of elasticity in longitudinal direction composite materials.
Fig. 17. Comparison between experimental and theoretical work for modulus
of elasticity in transverse direction composite materials.
Fig. 18. Buckling load of simply supported composite plate with various sisal
volume fraction.
IV. NUMERICAL INVESTIGATION
The finite element method is used to numerically determine
the buckling load of composite plate, where the well-known
commercial code ANSYS 14.0 is employed. The element type
used to determine the buckling load is Shell 281 because it can
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be used to layer the applications for composite shell or
sandwich construction modeling. Besides, this element is
suitable for analyzing thin shell to moderately-thick shell
structures. In addition, the element is suitable for linear, large
rotation and/or large strain nonlinear applications. The
element has eight nodes with six degrees of freedom at each
node: translations in the x, y, and z axes, and rotations about
the x, y, and z axes. The geometry and nodes of the element
type Shell 281 are shown in Fig. 19, [13].
Fig. 19. Geometry and Nodes of Sell 281.
In order to compare the numerical results with the
experimental results, data are required for filling out the fields
of ANSYS. These data (E1 and E2) can be extracting from
tensile test as shown in Fig. 4. Other data (shear modulus and
Poisson's ratio) are estimated from theoretical equations (eqs.
3-5). The mechanical properties, mentioned above, are listed
in table IV, and used to evaluate the buckling load using
Ansys program for the experimental and numerical
comparisons.
Table IV
Experimental and theoretical input mechanical properties required for Ansys.
Sample ( )
( )
( )
1 100 0 3.75 3.75 1.43 0.4
2 90 10 4.38 3.84 1.53 0.392
3 80 20 5.18 4.25 1.64 0.384
4 70 30 5.53 4.53 1.77 0.376
5 60 40 6.03 4.96 1.92 0.368
Similarly, for the comparison of the analytical and numerical
results of the bucking load, mechanical properties are required
to be used in ANSYS. These properties (modulus of elasticity
E1, E2, shear modulus G12 and Poisson's ratio ) can be
extracting from analytical equations (eqs. 3-6), as listed in
Table III.
Figs. 20 and 21, present the comparison between the
experimental and numerical works of the buckling load of
SSFF and CCFF composite plate. Good agreements with
maximum error about (12.6%) were shown in there figures.
Also, Fig. 22 shows the comparison between the analytical
and numerical results of simply supported composite plate for
various sisal volume fractions. Good agreement with
maximum error about (3.9%) was also shown in Fig. 22.
Then, the comparison of the buckling load with different
boundary condition of plate can be shown in Fig. 23, where
Fig. 23 shown the numerical results for buckling load with
various fiber volume fraction for different plate boundary
condition as (SSSS, SSFF, CCFF), and then, the figure shown
that the buckling load of simply supported plate greater than
buckling load for other supported plate. Since, the fixed and
stiffness of simply supported greater than for other supported.
Fig. 20. Comparison between experimental and numerical buckling load
results of SSFF plate.
Fig. 21. Comparison between experimental and numerical buckling load
results of CCFF plate.
Fig. 22. Comparison between theoretical and numerical buckling load results
of SSSS plate.
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Fig. 23. Numerical buckling load for different sisal volume fraction and
various boundary condition of composite plate.
V. CONCLUSION
From the results discussed earlier regarding the mechanical
properties and buckling load obtained experimentally and
theoretically along with the comparison of the results found
with the numerically computed data, the following remarks
can be concluded,
1. The comparison between experimental and numerical
results showed a good agreement with maximum error
about (12.6%). Hence, the experimental work is a powerful
technique to evaluate the buckling load of composite plate.
2. As the comparison between the theoretical and numerical
results showed a good agreement with maximum error
about (3.9%), the theoretical work can be considered as a
powerful technique to evaluate the buckling load of simply
supported composite plate.
3. The sisal reinforcement fiber causes an increase in the
strength of composite materials; hence, increasing the
volume fraction of sisal reinforcement fiber improves the
modulus of elasticity (mechanical properties of composite
materials).
4. Increasing the volume fraction of reinforcement fiber
causes an enhancement in the composite materials
strength, thus, increasing the sisal reinforcements leads to
improving the buckling load of composite plate with
different boundary conditions.
5. Fixing the plate from all sides causes an increase in the
plate strength; therefore, the buckling load of composite
plate is enhanced. Thus, the buckling load of SSSS is
greater than it is for both the SSFF and CCFF. Also, the
buckling load of CCFF plate is greater than it is for the
SSFF composite plate.
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