In the recent trends, several researches are happening in the area of Composite Materials especially in the case of hybrid composites to avail the higher properties of the hybridized fibres. It has become more challenging in the Aerospace industry as it is essential to develop a material which satisfies all property strength and to attain better strength to weight ratio. In this line of research, properties such as tensile, compression, shear and flexural are considered for the materials with the hybridization of E-glass in Kevlar 49 fibres at different orientation. Initially experimental analyses were done on these materials at a constant volume fraction of varying orientation and obtained the property strength values as per ASTM standard of composite material test procedure. In continuation to this experimental work, detailed Finite Element Analysis on same configuration is conducted using ANSYS. The primary objective is to do static structural analysis of the hybrid composites under tensile, compression, shear and flexural load and to validate with the experimental results.

1. http://www.iaeme.com/IJMET/index.asp 446 editor@iaeme.com
International Journal of Mechanical Engineering and Technology (IJMET)
Volume 9, Issue 11, November 2018, pp. 446–454, Article ID: IJMET_09_11_043
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=9&IType=11
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication Scopus Indexed
FINITE ELEMENT ANALYSIS OF COMPOSITES
UNDER DIFFERENT LOAD CONDITIONS WITH
THE EFFECT OF HYBRIDIZATION OF GLASS
REINFORCEMENT ON KEVLAR FIBRES
Anu Jacob Paul
Associate Professor, North Malabar Institute of Technology, Kerala, India
Research Scholar, Karunya Institute of Technology and Sciences, Coimbatore, India
S Darius Gnanaraj
Professor, School of Mechanical Engineering, VIT University, Vellore,
Tamil Nadu, India
ABSTRACT
In the recent trends, several researches are happening in the area of Composite
Materials especially in the case of hybrid composites to avail the higher properties of
the hybridized fibres. It has become more challenging in the Aerospace industry as it
is essential to develop a material which satisfies all property strength and to attain
better strength to weight ratio. In this line of research, properties such as tensile,
compression, shear and flexural are considered for the materials with the
hybridization of E-glass in Kevlar 49 fibres at different orientation. Initially
experimental analyses were done on these materials at a constant volume fraction of
varying orientation and obtained the property strength values as per ASTM standard
of composite material test procedure. In continuation to this experimental work,
detailed Finite Element Analysis on same configuration is conducted using ANSYS.
The primary objective is to do static structural analysis of the hybrid composites
under tensile, compression, shear and flexural load and to validate with the
experimental results.
Key words: Hybrid composites; Kevlar glass fibre; Epoxy LY5052, FEA; Mechanical
properties; ANSYS.
Cite this Article: Anu Jacob Paul and S Darius Gnanaraj, Finite Element Analysis of
Composites Under Different Load Conditions with the Effect of Hybridization of
Glass Reinforcement on Kevlar Fibres, International Journal of Mechanical
Engineering and Technology 9(11), 2018, pp. 446–454.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=9&IType=11

2. Anu Jacob Paul and S Darius Gnanaraj
http://www.iaeme.com/IJMET/index.asp 447 editor@iaeme.com
1. INTRODUCTION
Hybrid composites are developed by incorporating two or more fibres in a matrix. It may also
have two resin systems also. Hybrid Composites in short named as “hybrids”. There are many
researches happening in the automobile and aerospace application. The utilization of hybrid
composites is expanding rapidly, and they have been acknowledged as structural materials
with superior properties [1]. Much research has been done through the investigation of
hybrids with the mix of carbon and glass fibre. There are several configurations of hybrids
like, fibre by fibre mixture, tow by tow and layer by layer mixtures. In this research work,
hybridization of E-glass fibre with Kevlar49 in an epoxy resin matrix system LY5052. Kevlar
49 used here is in the form of bidirectional fibre with mild varying properties in wrap and
weft directions of the woven mat. Kevlar forms a strong and flexible material. Kevlar fibres
are strengthened with the layers of resin to develop a rigid material which is light having high
strength compared to steel [4].
E-glass, very commonly used as reinforced fibre in composites, creates textures with
incredible dimensional stability under different kinds of loading conditions. Glass fabrics
show good heat resistance at relatively low cost. Glass fibres are durable, and exhibits better
thermal conductivity and chemical resistance. LY5052 epoxy commonly used in Aerospace
industry having low viscosity provides better mechanical and dynamic behaviour even when
cured at room temperature.
The results of the experimental analysis and the finite element analysis (ANSYS) of the
laminates of above hybrid configuration are studied to validate the strength values of this
reinforced composite material.
The significant application of the developing composite material is in aircraft wing box
construction [3]. It makes stronger, lighter weight, and a thicker frame to build a wing. A
wing box made of 3 basic components like skin, ribs and spars is designed to react mainly the
bending and the shear loads developed in the wing. Wing box also acts as a torque box which
resists the torsional loads.
2. EXPERIMENTAL WORK
Layer by layer lamina are stacked to develop the laminates of thickness approximately 3.2mm
[2]. For the experimental analysis of the properties, nine laminates of different orientations
were prepared as shown in Table1. Layers of Kevlar, E-Glass and the corresponding bonding
material LY5052 are taken to process the laminates [2].
Table 1 Stacking sequence of the laminates with orientations
1 2 3 4 5 6 7 8 9
K00
G00
K900
G900
K00
G450
K900
G450
K00
G900
K900
G00
K450
G00
K450
G900
K450
G450
6 layers of Kevlar and 5 layers of E glass arranged alternatively. Top and
bottom layer as Kevlar
Laminates are processed using vacuum bag technique. Raw materials weight and volume
fraction in all laminates are kept constant and only orientation has been changed. Further tests
like tensile, flexural, compression, shear and impact were conducted in our previous work [2]
to obtain the strength and modulus values in both longitudinal and lateral direction of the
laminates.

3. Finite Element Analysis of Composites Under Different Load Conditions with the Effect of
Hybridization of Glass Reinforcement on Kevlar Fibres
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3. FINITE ELEMENT ANALYSIS
The scope of work is static structural analysis of hybrid composites [5] under loading
conditions of tensile load, compressive load, shear load and flexural load. Here again nine
laminates of the same stacking sequences as of experimental work are taken (Table 1).
Dimensions of test piece are also taken as same as experimental work as per ASTM standards.
All laminates are modelled according to the input details available for the raw materials as per
the details given in Table 2.
Table 2 Input details of Raw Material’sproperties
Properties Kevlar 49 E-Glass EpoxyLY5052
Density (Kg/m3
) 1440 2580 1170
Young’s Modulus[GPa]
Ex 80 41 3.64
Ey 72 12 3.64
Ez 72 12 3.64
Poison’s ratio
Vxy 0.34 0.28 0.35
Vxz 0.34 0.28 0.35
Vyz 0.4 0.5 0.35
Shear modulus [Gpa]
Gxy 2.2 5.5 3.30
Gxz 2.2 5.5 3.30
Gyz 1.8 3.5 3.30
Layer Thickness [mm] 0.25 0.2 0.07 (avg)
Analysis of mathematical model of laminates was carried out. The procedures adopted
are, Input study & Identifying geometry details of model for analysis; Generate new FE model
based on the dimensions; Structural analysis with applied force and further deformation and
von misses stress are evaluated on various cases.
3.1. FEA on Tensile Property
For comparison of FEA with experimental strength values on tensile property, all nine
laminates are prepared as per ASTM dimensions (ref fig 1a). Each laminates are modelled
separately (sample model of laminate-1 is referred in Fig 1b) and gradually applied loads
were considered at the boundary condition till the peak load is obtained. The peak load taken
with respect to the loads obtained during the experimental work and these loads (in N) of each
laminates are 11240, 13578, 12211, 11493, 10017, 15950, 10499, 2487, and 3709(N)
respectively.
Figure 1 a) Specimen dimension as per ASTM standard b) Sample model of laminate 1

4. Anu Jacob Paul and S Darius Gnanaraj
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These laminates under varying gradually applied load were further simulated and analysed
the stress- strain and the load-deflection behaviour of the developed composites to obtain the
tensile strength value (ref fig 2a and 2b). For the laminate 1, the tensile strength in
longitudinal fibre direction is 333 MPa. Similarly the strength values are obtained for all the
laminates and the comparison with its experimental values are illustrated graphically below
(ref fig 3). Sample deformation and equivalent stress plots of laminate-1 analysed in ANSYS
are also presented in Fig 4. The comparison of deformation of all laminates is shown in Fig 5.
Figure 2 a) Load – deflection behaviour for laminate-1, b) Stress strain behaviour for laminate-1
Figure 3 Comparison of FEA Tensile strength value in longitudinal direction of all laminates with
Experimental values
Figure 4 a) Sample deformation plots of laminate -1 in ANSYS b) Sample equivalent Von mises plots
of laminate-1

5. Finite Element Analysis of Composites Under Different Load Conditions with the Effect of
Hybridization of Glass Reinforcement on Kevlar Fibres
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Figure 5 Comparison of deformation under tensile load of all laminates
3.2. FEA of Compressive strength property
Static structural analysis with boundary condition of compressive forces applied at both ends.
It is modelled again as per the geometry of ASTM standard on compressive test in reinforced
polymers, which is a rectangular shape of 100x12.5mm with 3.2mm thickness (ref fig 6).
Maximum compressive load as per the experimental test to delamination is again considered
as the peak load in FEA compressive analysis by applying it gradually at certain intervals. For
all laminates the load taken in “N” are 1425, 1895, 559, 573, 791, 1090, 1816, 1257 and 664
N respectively. The comparison of compressive strength is given in figure=7. Deformation
and stress plots using ANSYS of laminate – 1 are given in f figures 8a and 8b. The
comparison of deformation under compression for all laminates is given in figure 9.
Figure 6 Sample model of laminate – 1 as per ASTM geometry
Figure 7 Comparison of FEA Compressive strength value in longitudinal direction of all laminates
with Experimental values

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Figure 8 a) Sample deformation plots of laminate -1 in ANSYS b) Sample equivalent Von mises plots
of laminate-1
Figure 9 Comparison of deformation under compressive load of all laminates
3.3. FEA of Flexural Property
Three point bending test and analysis of 3D model of FRP are carried out. Static structural
analysis carried out on beams supported at both ends under various bending loads applied at
mid-point of the beam. Geometry is taken as per ASTM as 130x12.7x3.2mm. The
displacement of Uz is constrained on both ends of beam as shown in figure 10. Bending loads
are applied gradually at the mid-point of the simply supported beam to the experimental peak
load withstood by the specimen before the onset of delamination or failure took place. And
the loads considered for all laminates are 226, 290, 119, 156, 176, 217, 309, 144 and 109 N
respectively. Comparison of flexural strength obtained through FEA of each laminate with
experimental values is shown in figure 11. Deformation and stress plots of laminate – 1 using
ANSYS are shown in figs 12a and 12b. The comparison of mid-point deformation under
bending load for all laminates are illustrated is shown in figure 13.
Figure 10 Sample model of laminate – 1 with boundary condition as per ASTM geometry

7. Finite Element Analysis of Composites Under Different Load Conditions with the Effect of
Hybridization of Glass Reinforcement on Kevlar Fibres
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Figure 11 Comparison of FEA Flexural strength value in longitudinal direction of all laminates with
Experimental values
Figure 12 a) Sample deformation plots of laminate -1 in ANSYS b) Sample equivalent Von mises plots of
laminate-1
Figure 13 Comparison of mid-point deformation under bending loads of all laminates
3.4. FEA of Shear Property
3D model with dimensions 50x16x3.2mm are analyzed. The boundary conditions are applied.
The displacement constraints of Uy & Uz are fixed. Shear forces are applied along X
direction of the beam as shown in fig 14. Shear forces of 7080, 6433, 6034, 5292, 6323, 8164,
8222, 7041 and 9137 N respectively are applied on laminates with respect to the peak load
from experimental results. Shear strength values are obtained and the comparison between
experimental values and values obtained through simulation is shown graphically in figure15.
Deformation and stress plots of laminate-1 using ANSYS are shown in figs 16a and 16b.
Comparison of deformation under shear load for all laminates is shown in figure-17.

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Figure 14 Sample model of laminate – 1 with boundary condition as per ASTM.
Figure 15 Comparison of FEA Shear strength value in longitudinal direction of all laminates with
Experimental values.
Figure 16 a) Sample deformation plots of laminate -1 in ANSYS b) Sample equivalent Von mises
plots of laminate-1
Figure 17 Comparison of deformation under shear loads along X Direction of beam in all
laminates

9. Finite Element Analysis of Composites Under Different Load Conditions with the Effect of
Hybridization of Glass Reinforcement on Kevlar Fibres
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4. DISCUSSIONS
Both experimental and the FEA results were compared. In most of the cases, the values are
comparatively closer to each other. However in few cases, compression test in laminate-7 and
tensile test in laminate-9 show larger differences.
From the above results, it is seen that the laminates 2 and 6 are comparatively better in
tensile strength having lesser deformation. Laminates 2 and 8 are better in compressive
strength with more deformation. Laminates 2 and 7 have higher bending strength;
deformation of laminate 2 is smaller but the deformation of laminate 7 is very high.
Laminates 5 and 6 have high shear strength but the shear deformation is high. It can be said
that laminate 2 is the best composite compared to all other composites. Laminate 2 has
orientation of K90°/G90°. It has been observed that the hybridization of E-glass with a
constant Kevlar orientation of 90o
is much superior in most of the properties compared to
other laminates. Also, the volume fraction for all laminates is same as we have taken the same
number of layers of Kevlar and E-glass.
5. CONCLUSIONS
Finite element analysis carried out on 9 laminates of hybrid composites with different
orientations. Simulations were made using tensile, compressive, bending and shear loads. The
results were compared with experimental results and comparison is closer for many laminates.
Laminate-2 with orientation K90°/G90° was found to have good tensile, compressive and
bending properties compared to other laminates.
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[2] Anu Jacob Paul and Darius Gnanraj S, “The Effects of Hybridization of Glass Fiber on the
Mechanical Properties of Kevlar Composites with LY5052 Epoxy Polymer Matrix”,
Proceedings of International Conference on FEAST, NIT Trichy, Vol-2, ISBN 978-81-
908388-8-7, 2017
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