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MODE II + III DELAMINATION BEHAVIOUR OF FLAX FABRIC
REINFORCED POLYMER COMPOSITE
MOHD HAFIDZUL BIN SALLEH
A project report submitted in partial fulfilment of the
requirements for the award of the degree of
Master of Science (Mechanical Engineering)
Faculty of Mechanical Engineering
Universiti Teknologi Malaysia
SEPTEMBER 2017
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Dedicated to
My Family
&
Special dedication to
My Wife & Children
iv
ACKNOWLEDGEMENT
Alhamdulillah, I am very grateful and would like to thank all the people who
contribute in some way to the work describe in this thesis.
First and foremost I wish my deepest gratitude and my sincere appreciation to
my academic supervisor, Dr Wong King Jye, his excellent guidance, caring, patience
and providing me constant motivation throughout the course of work. Without his
guidance and persistent help this dissertation would not have been possible.
Special appreciation goes to the staff of Mechanical Engineering department
for providing laboratory facilities to complete my experiment work. My research
experiment will not have been possible without their helps.
I would like to thanks my wife and my four wonderful children for being
pillar for me and provide moral support throughout this course of study as well. My
parent who always pray for me and let his son to strive his ambition and sharing this
valuable knowledge to others. I would not be who am I today without them.
Last but not least, I would like to thank my friends who lend their hand to
assist me to complete my final year project successfully.
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ABSTRACT
Flax fibres, along with a number of other natural fibres are being considered
as environmentally friendly alternative of synthetic in fibre reinforced polymer
composite. This paper deals with mode II & III mixed mode delamination behaviour
of flax behaviour of flax fabric reinforced polymer composite experimentally. The
six point bending (6PBP) test was proposed and developed to obtain mixed mode
ratios (II +III). The specimens used for six-point bending plates with woven flax
fabric reinforced polymer composite. The experiment result shows non-uniform
distribution of GII and GIII and considerable geometric non-linearity. 6PBP testing
carried out based on different parameter of dimension (type II & type III) and type of
Teflon.
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ABSTRAK
Serat rami (Flax) yang merupakan salah satu serat semulajadi dikategorikan
sebagai serat yang mesra alam sekitar. Serat Flax adalah alternatif kepada serat
sintetik polimer bertetulang. Dalam tesis ini, sifat sempadanan mod tergabung II + III
untuk serat flax polimer bertetulang di kaji dengan menjalankan ujikaji makmal.
6PBP iaitu suatu keadah ujikaji yang dicadangkan dijalan kan untuk mencari mod
tergabung II + III. Bahan ujikaji yang di gunakan adalah serat rami (Flax) sintetik
polimer bertetulang komposit. Hasil ujikaji yang dijalankan menunjukkkan,
ketidakseragaman nilai bagi ketegangan patah bagi mod II (GII) dan mod III (GIII)
dan boleh diklasifikasikan sebagai geometri bukan linear. Pengujian 6PBP yang telah
dijalankan di uji dengan mempelbagaikan parameter dari segi ukuran saiz bagi iaitu
jenis II dan jenis III. Paramater lain yang diuji adalah dari segi jenis Teflon yang
berlainan .
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TABLE OF CONTENTS
CHAPTER TITLE PAGE
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES ix
LIST OF FIGURES x
LIST OF ABBREVIATIONS xii
1 INTRODUCTION
1.1 Research background 1
1.2 Research objectives 2
1.3 Problem Statements 2
1.4 Scope of research 2
1.5 Theorectical framework 3
1.6 Thesis outline 4
1.7 Research methodology and flowchart 5
2 LITERATURE REVIEW
2.1 Introduction 7
2.2 Flax Fiber epoxy composite 7
2.3 Mode of fracture 7
2.4 Interlaminar fracture toughness 11
2.5 Mixed mode II + III 11
3 RESEARCH METHODOLOGY
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3.1 Introduction 14
3.2 Experimental Conduct 14
3.3 Material Selection 15
3.4 Fabrication process 18
3.4.1 Marking and measurement 19
3.4.2 Cutting Flax fiber sheet 20
3.4.3 Hand lay-up with epoxy and Teflon 22
3.4.4 Vacuum Begging 25
3.4.5 Dimension marking 27
3.4.6 Cutting fabricated flax composite 28
3.4.7 Six point bending plate 29
3.4.7.1 Experiment set up 30
3.4.7.2 Flax sample readiness 31
3.4.7.3 Mixed mode II + III 32
3.5 Apparatus 33
3.5.1 Testing machine – Shimadzu AG-X10kN 33
3.5.2 Mixed mode II + III testing jig 34
4 RESULTS AND DICUSSIONS
4.1 Introduction 35
4.2 Experiment result of 6PBP mixed mode 35
4. 2.1 Type II result 36
4. 2.2 Type II result 38
4.3 Result discussion 41
5 CONCLUSION AND RECOMMENDATION
5.1 Conclusion 42
5.2 Recommendation 45
REFERENCES
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LIST OF TABLES
TABLE NO TITLE PAGE
2.1 Density and tensile properties of different natural and
syntactic fiber
8
3.1 Type of dimension 31
4.1 Average critical fracture load for type II + III flax composite 40
4.2 Average critical fracture load for type II + III polymeric
woven fabric
40
x
LIST OF FIGURES
FIGURE NO TITLE PAGE
1.1 Scope of research 2
1.2 Theoretical framework 3
1.3 Flowchart of research 6
2.1a Opening mode, mode I 10
2.1b Sliding mode, mode II 10
2.1c Tearing mode, mode III 10
2.2 6PBP testing of Flax epoxy laminated configuration 12
2.3 6PBP testing of Flax polymeric woven fabric
configuration
13
3.1 Experiment research methodology framework 15
3.2 Main material flax fiber 16
3.3 Pre-cut flax fiber 16
3.4 Hardener and epoxy 1006 series 17
3.5 Laminated Teflon 17
3.6 Fabrication process 18
3.7 Marking 19
3.8 Measurement 19
3.9 Cutting process 20
3.10 Cutting to final dimension 20
3.11 Flax fiber sheet dimension 21
3.12 Teflon dimension 21
3.13 Mixture of epoxy with hardener 22
3.14 Stir the mixture 22
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LIST OF FIGURES
FIGURE NO TITLE PAGE
3.15 Arrangement of flax fiber 24
3.16 Arrangement of flax fiber with Teflon 24
3.17 Teflon covering 25
3.18 Vacuum begging 25
3.19 Fabricated sample 26
3.20 Dimension marking with plan 27
3.21 Cutting process 28
3.22 Mechanical testing 29
3.23 Experiment set up 30
3.24 Flax readiness 31
3.25 Mixed mode II + III testing 32
3.26 Shimadzu AG-X10kN 33
3.27 Testing jig 34
4.1 Force (N) versus displacement sample 1 type II 36
4.2 Force (N) versus displacement sample 2 type II 36
4.3 Force (N) versus displacement sample 3 type II 37
4.4 Force (N) versus displacement sample 4 type II 37
4.5 Force (N) versus displacement sample 1 type III 38
4.6 Force (N) versus displacement sample 2 type III 38
4.7 Force (N) versus displacement sample 3 type III 39
4.8 Force (N) versus displacement sample 3 type III 39
4.9 Flax epoxy plate 40
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LIST OF ABBREVIATIONS
6PBP - Six point bending plate
G - Energy release
DCB - Double cantilever beam,
MMB - Mixed-mode bending
UD - Tests on unidirectional
MD - Multidirectional
STB - Shear-torsion bending
Gj (j = I, II, III) - Energy release rate component
P - Applied Load
S - Span
N - Forces
1
CHAPTER 1
INTRODUCTION
1.1 Research Background
In recent days, environmental health aspects and increase in pollution have
become each and every nation issue to provide better sustainable development for the
public. Flax fiber along with number of other natural fibers, are being considered an
environmentally friendly alternative of synthetic fibers in fiber-reinforced polymer
composite. The common feature of natural fiber is much higher variability of
mechanical properties [1]. This necessitates study of flax fiber particularly it employ
in automotive industry, apparel, fabric, decoration and insulation.
Characterization of delamination resistance of high performance laminated
composite has been subject of considerable research Delamination propagation is one
of the most common degradation mechanisms of continuous fiber reinforced
polymer-matrix composite material [6]. Because of laminated structure, delamination
may easily occur in fiber-reinforced composites due to manufacturing defect, impact
of object and high stress concentrations from geometrical discontinuity. In general,
they cause a considerable reduction in crack growth resistance facture toughness.
2
1.2 Research Objective
The objective for this research is:
To study delamination behavior of flax-fabric reinforced composite polymer under
mode II + III loading.
1.3 Problem Statements
Delamination propagation is one of the most common degradation
mechanism of continuous fiber reinforced polymer-matrix composite [6].
Characteristic of delamination under basic loading mode II + III are one of the
factors which determine performance of flax-epoxy polymer reinforced composites
1.4 Scope of Research
In this research brief description on delamination behaviour will be discussed.
The experiment of 6PBP setting up of mode II + III under type II and III will be
shown in this research. Sequence of experiment starting from materials, fabrication,
sampling and testing will be shown below diagram.
Figure 1.1 Scope of research
Material Fabrication Sampling Testing
3
1.5 Theoretical Framework
This study will determine the delamination behavior of flax epoxy composite
under mode II + III loading. Figure 1.1 summaries the frame work of this research.
Figure 1.2 Theoretical Framework
Phase 1: Fabrication Flax
composite fibre
Side View
Top View
6PBP Testing
(Mode II + III)
Phase 2: Mechanical Testing
Phase 3: Analysis
Experiment Analysis
Evaluation of G value &
comparison with other
material
Brown: Flax Fibre
Red: Epoxy
Blue: Teflon
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1.6 Thesis Outline
Chapter 1 presents on the research introduction. In this chapter, the research
background, problem statement, objective and scope of this study, research
contribution, methodology of research and overall thesis outline has been discussed.
Chapter 2 presents the literature review related subjects concerning to the
research done. In this chapter, the extensive literature review has been done on
flax/epoxy composite, delamination of flax/epoxy composite and type of testing
method mixed mode I+III conducted related with delamination
Chapter 3 presents methodology and experimentation of flax epoxy
composite under 6PBP testing. Sets of apparatus and experiment set up elaborated in
this chapter for mixed mode II + III.
Chapter 4 presents the results obtained by conducted 6PBP testing for mixed
mode II + III. Resulted indicated average critical load applied for set of sample under
type II and type III of 6PBP testing. Graph force against displacement been plotted,
analyzed and discussed. Discussion on the delamination behavior from previous
established data and research related to force and displacement been discussed and
compared.
.
Chapter 5 is concluding chapter. This chapter summarizes the works done in
the entire research on this thesis. The directions and recommendations for future
research works are also have been described in this chapter.
5
1.7 Research Methodology and Flowchart
The methodologies involved in this research have been shown in Figure 1.3.
The research started with gathering and collecting literature review from different
mean of reading material such as books, journals and technical papers related to
delamination of flax epoxy under mixed mode II + III
The materials collected from the literature review have been extensively
utilise and extracted to garner main understanding and concept in order to carry out
six-point bending plate testing (6PBP) of Flax epoxy composite. Based on reviewed,
more extensive study need to carry out especially for delamination of flax epoxy
composite under mixed mode II + III.
Until now, since first test carried out for delamination under mode II + III,
several set up of standard method has been proposed which included recently
modified test method organised by the ASTM committee, but yet to achieved
specific standard of mixed mode II + III.
Nevertheless, several extensive studies done by researchers to analyse of
mixed mode II + III interlaminar crack growth in other polymer used as a guideline
and comparison with variable parameter. In this research of flax fibre composite,
experiment of variable parameters being use in term of different dimension of
specimen and type of Teflon.Finally, the thesis has been concluded and future
recommendation has suggested for further improvement of analysis of mixed mode II
+ III delamination of flax fibre.
6
Figure 1.3 Flowchart of research
44
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