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APPLICATION OF INTEGRATED ANALYTIC
HIERARCHY PROCESS (AHP) AND TECHNIQUE OF
ORDER PREFERENCE BY SIMILARITY TO IDEAL
SOLUTION (TOPSIS) IN MATERIAL SELECTION FOR
AUTOMOTIVE FENDER DESIGN
GOH CHIA MIN
B051110126
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2015
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
APPLICATION OF INTEGRATED ANALYTIC HIERARCHY
PROCESS (AHP) AND TECHNIQUE OF ORDER PREFERENCE
BY SIMILARITY TO IDEAL SOLUTION (TOPSIS) IN
MATERIAL SELECTION FOR AUTOMOTIVE FENDER
DESIGN
This report submitted in accordance with requirement of the Universiti Teknikal
Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Manufacturing Design) (Hons.)
by
GOH CHIA MIN
B051110126
911018-04-5520
FACULTY OF MANUFACTURING ENGINEERING
2015
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: APPLICATION OF INTEGRATED ANALYTIC HIERARCHY PROCESS (AHP) AND TECHNIQUE OF ORDER PREFERENCE BY SIMILARITY TO IDEAL SOLUTION (TOPSIS) IN MATERIAL SELECTION FOR AUTOMOTIVE FENDER DESIGN
SESI PENGAJIAN: 2014/15 Semester2 Saya GOH CHIA MIN mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan
pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan ( )
SULIT
TERHAD
TIDAK TERHAD
(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
Alamat Tetap:
40, Jalan Murni 12,
Taman Malim Jaya,
75250 Melaka.
Tarikh: 20th June 2015____________
Disahkan oleh:
Cop Rasmi: Tarikh: _______________________
** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.
DECLARATION
I hereby, declared this report entitled ‘Application of Integrated Analytic Hierarchy
Process (AHP) And Technique of Order Preference by Similarity to Ideal Solution
(TOPSIS) In Material Selection for Automotive Fender Design' is the results of my
own research except as cited in references.
Signature : …………………….
Author’s Name : GOH CHIA MIN
Date : 20th June 2015
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a
partial fulfilment of the requirements for the Degree of Manufacturing Engineering
(Manufacturing Design) (Hons.). The member of the supervisory committee is as
follow:
……………………………………
(Supervisor)
(PROF. MADYA DR. HAMBALI BIN AREP@ARIFF)
i
ABSTRACK
Laporan ini merupakan kajian tentang Integrasi AHP dan TOPSIS dalam
proses pemilihan bahan untuk reka bentuk fender automotif. Bahan-bahan untuk
pembinaan kenderaan automotif telah ditukar dari besi tuang dan keluli karbon
rendah kepada bahan-bahan yang ringan seperti rencam matriks polimer, aloi
magnesium dan aloi aluminium. Oleh itu, pemilihan bahan fender automotif dalam
laporan ini akan memberi tumpuan kepada bahan-bahan ringan kerana trend baru
dalam menghasilkan kenderaan ringan dalam industri automotif. Objektif utama
adalah menentukan bahan yang terbaik bagi fender automotif dengan menggunakan
kaedah integrasi AHP-TOPSIS dan megenalpastikan kriteria yang penting dalam
pemilihan bahan untuk fender automotif. Pemilihan bahan adalah berdasarkan
rekabentuk sedia ada dan proses pembuatan untuk fender automotif. Sifat-sifat bahan
penting yang perlu dipertimbangkan dalam pemilihan bahan adalah prestasi, kos,
berat dan pembuatan untuk fender automotif. Sepuluh bahan calon yang dicadangkan
adalah keluli kekuatan tinggi, Aluminium aloi dan termoplastik. Pertama, kaedah
AHP telah digunakan untuk menentukan keberatan untuk setiap kriteria. Kemudian,
kaedah TOPSIS digunakan untuk melaksanakan kedudukan alternatif dalam
pemilihan bahan untuk fender automotif. Kaedah integrasi AHP-TOPSIS telah
membuktikan sangat berguna semasa membuat keputusan yang melibatkan pelbagai
kriteria dan alternatif seperti proses pemilihan bahan untuk fender automotif.
Kesimpulannya, resin PPE/PA/989 telah dipilih sebagai bahan yang terbaik bagi
fender automotif dengan mengunakan kaedah integrasi AHP-TOPSIS.
ii
ABSTRACT
This report was study about integration of AHP and TOPSIS in the material
selection process of an automotive fender design. The materials for the construction
of automotive vehicles are rapidly changed from cast iron and low carbon steel
towards lighter materials such as polymer matrix composites, magnesium alloys and
aluminium alloys due to greater emphasis on the weight reduction vehicles. The
material selection of the automotive fender will focused on lighter materials due to
new trend in producing light weight vehicles in automotive industry. The main
objective was to determine the best material for automotive fender using integrated
AHP-TOPSIS method by identified important criteria in material selection of the
automotive fender. The material selection was based on existing design and
manufacturing process of the automotive fender. The material property needs to be
considered in the material selection was Performance, Cost, Weight and
Manufacturing criteria. Ten candidate materials proposed were High Strength Steel,
Aluminium Alloy and Thermoplastic. First, AHP method was used to determine the
weight of the selection criteria. Then, TOPSIS method was used to perform the
ranking of alternatives. The integrated AHP-TOPSIS method was proven very
successfully in multi-criteria decision making processes which involved many
criteria and alternatives in the material selection of the automotive fender. As a
conclusion, the PPE/PA/989 resin was selected as the best material for the
automotive fender using integrated AHP-TOPSIS method.
iii
ACKNOWLEDGEMENT
In performing this project, it would not have been possible without the kind
support and help of many individuals and university. I would like to extend my
sincere gratitude and appreciation to all of them.
First and foremost, special thanks to my supervisor, Prof. Madya Dr. Hambali
Bin Arep @Ariff for his vital encouragements, guidance and constant supervision as
well as for providing necessary information regarding this project.
In addition, I would like to acknowledge with much appreciation the crucial
role of my parents who supported me in any respect during the completion of this
report. They always remind me that my report should always be useful and serves
good purposes to all mankind. They showed me different ways in approaching a
problem and made me realize the value of persistent in accomplishing any goals.
An honorable mention goes to my friends who have willingly helped me out
with their abilities by sharing with me their experiences in report-writing and
providing me their valuable comments and suggestions which gave me an inspiration
to improve my project. Last but to least, I offer my regards and blessings to all of
those who helped me in putting pieces together.
iv
DEDICATION
Dedicated to my beloved father, Goh King Chong,
my appreciated mother, Chong Ah Kim
and my adored sisters and brother, Goh Chia Nee, Goh Chia Han and Goh Chia
Chia for giving me moral support, cooperation, encouragement and also
understandings.
v
TABLE OF CONTENTS
Abstrak i
Abstract ii
Acknowledgement iii
Dedication iv
Table of contents v
List of Tables ix
List of Figures x
List of Abbreviations xi
List of Symbols xii
CHAPTER 1: INTRODUCTION 1
1.1 Background 1
1.2 Problem Statement 4
1.3 Objectives 5
1.4 Scopes of Research 5
CHAPTER 2: LITERATURE REVIEW 6
2.0 Overview 6
2.1 Introduction of Automotive Fender 6
2.2 Existing Material Used For Automotive Fender 7
2.2.1 Steel 8
2.2.2 Plastic 8
2.2.3 Noryl GTX resin 8
2.2.4 High modulus ductile (HMD) resin 10
2.2.5 Carbon fiber 10
2.2.6 Aluminium-Blech 11
2.3 Automotive Fender Material Selection Criteria 12
2.3.1 Density 12
2.3.2 Cost 12
2.3.3 Painting capability 13
vi
2.3.4 Design freedom 14
2.3.5 Performance requirements 14
2.4 Lightweight Materials Used in Automotive Industry 14
2.4.1 Steel 14
2.4.2 Aluminium Alloys 16
2.4.3 Magnesium Alloys 19
2.4.4 Titanium Alloys 20
2.4.5 Stainless Steels 20
2.4.6 Cast Iron 21
2.4.7 Polymer Matrix Composites 22
2.4.7.1 Thermoplastics and Thermoplastics 22
Matrix Composites
2.4.7.2 Thermoset–Matrix Composites 23 2.5 Analytic Hierarchy Process (AHP) 25
2.5.1 Application of AHP in multi-criteria decision making 25
(MCDM) process
2.6 Technique For Order Preference By Similarity To Ideal Solution 27
(TOPSIS)
2.6.1 Application of TOPSIS in multi-criteria decision making 28
(MCDM) process
2.7 Integration of AHP-TOPSIS Method 28
2.7.1 Implementation of Integrated AHP-TOPSIS method 29
2.8 Other Material Selection Method 29
2.9 Summary and Research Gap 30
CHAPTER 3: METHDODOLOGY 32
3.0 Overview 32
3.1 Project Flow Chart 33
3.2 AHP Method 35
3.3 TOPSIS Method 39
CHAPTER 4: ANALYSIS USING INTEGRATED AHP-TOPSIS METHOD 44
4.0 Overview 44
vii
4.1 Data Collection 45
4.2 Weighting of Criteria Using AHP Method 47
4.2.1 Hierarchy Framework 47
4.2.2 Main Criteria With Respect To Goal 49
4.2.2.1 Pair-Wise Comparison 49
4.2.2.2 Consistency Analysis 50
4.2.2.2.1 Eigenvalue ((ƛmax) 50
4.2.2.2.2 Consistency Index (CI) 51
4.2.2.2.3 Consistency Ratio (CR) 52
4.2.3 Sub-Criteria With Respect To Main Criteria 52
4.2.4 Sub-Criteria With Respect To Goal 53
4.3 Ranking of Alternatives Using TOPSIS Method 54
4.3.1 Overall TOPSIS Decision Matrix 54
4.3.2 Normalized Decision Matrix 54
4.3.3 Weighted Normalized Decision Matrix 55
4.3.4 Positive Ideal Solution (PIS) and Negative Ideal Solution (NIS) 58
4.3.5 Separation Measures 58
4.3.6 Relative Closeness 59
CHAPTER 5: RESULTS AND DISCUSSIONS 61
5.0 Overview 61
5.1 AHP Results 62
5.1.1 Expert Choice TM Software 62
5.1.1.1 Main Criteria With Respect To Goal 62
5.1.1.2 Sub-Criteria With Respect To Main Criteria 64
5.1.1.3 Sub-Criteria With Respect To Goal 65
5.2 TOPSIS Results 66
CHAPTER 6: CONCLUSION AND RECOMMENDATIONS 68
6.1 Conclusion 68
6.2 Recommendations 68
REFERENCES 69
viii
APPENDICES
A Gantt Chart for FYP I
B Gantt Chart for FYP I
C AHP Analysis of Main Criteria With Respect to Goal
D AHP Analysis of Sub-criteria with Respect to Performance main criteria
E AHP Analysis of Main Criteria with Respect to Manufacturing Main
Criteria
F TOPSIS Analysis of Alternatives
ix
LIST OF TABLES
1.1 Material distributions in typical automobile 2
2.1 Steels categories, properties and application 16
2.2 List of aluminium alloys and automotive applications 18
2.3 Application of thermoplastics polymer in automotive industry 22
2.4 Polymer blends in automotive application 23
2.5 Application of AHP in MCDM process 27
2.6 Application of AHP in MCDM process 28
2.7 Implementation of Integrated AHP-TOPSIS method 29
2.8 Other Material Selection Method 30
3.1 Saaty rating scale for pair-wise comparison 37
3.2 Random Index (Saaty, 2001) 39
4.1 Material properties of candidate materials (MatWeb, 2012) 46
4.2 A hierarchy framework for the material selection 49
4.3 Pair-wise of main criteria 50
4.4 Synthesized pair-wise comparison and priority vector 50
4.5 Calculated the eigenvalue (ƛmax) 51
4.6 Consistency test for main criteria 52
4.7 Consistency test for sub-criteria of Performance 53
4.8 Consistency test for sub-criteria of Manufacturing 53
4.9 Overall priority vector 54
4.10 Overall TOPSIS decision matrix 56
4.11 Modified decision matrix 56
4.12 Normalized decision matrix 57
4.13 Weighted normalized decision matrix 57
4.14 PIS and NIS 58
4.15 Separation from PIS and NIS 59
4.16 Relative Closeness 60
5.1 Relative Closeness 67
x
LIST OF FIGURES
2.1 Automotive fender design 7
3.1 Project flow chart 33
3.2 AHP algorithm (Saaty, 2001) 36
3.3 A hierarchical framework 37
3.4 Flow chart of TOPSIS method 40
4.1 A hierarchy framework for the material selection 47
5.1 Tree diagram 62
5.2 Pair-wise comparison of the main criteria in matrix format 62
5.3 Pair-wise comparison of the main criteria in graphical 63
5.4 Local weight of the main criteria 63
5.5 Priority of the main criteria with respect to the goal 63
5.6 Pair-wise comparison of the Performance sub-criteria 64
5.7 Priority of the sub-criteria with Performance 64
5.8 Pair-wise comparison of the Manufacturing sub-criteria 65
5.9 Priority of the sub-criteria with Manufacturing 65
5.10 Global weight of the sub-criteria 66
5.11 Priorityof the sub-criteria with respect to the goal 66
5.12 Percentage of relative closeness of alternatives 67
xi
LIST OF ABBREVIATIONS
AA2036T4 - Aluminium Alloy 2036 in the T4 temper
AA6010T4 - Aluminium Alloy 6010 in the T4 temper
AHP - Analytic Hierarchy Process
AR/PC - Acrylic/Polycarbonate Alloy
CTE - Linear Coefficient of Thermal Expansion
D - Density
D1000DP - Docol Cold Rolled Steel 1000 Dual Phase
D600DP - Docol Cold Rolled Steel 600 Dual Phase
EB - Elongation at Break
ER - Electrical Resistivity
IP - Izod Impact, Notched
MC - Material cost
MCDM - Multiple-criteria Decision Making
NY66/40CF - Nylon 66 with 40% Carbon Fiber Filled
PC/PBT - Polycarbonate with Polybutylene Terephthalate Blend
PPE/PA/989 - Polyphenylene Ether with Polyamide Blend
PPO/PA66 - Polyphenylene Oxide with Nylon 66
PPS/40CF - Polyphenylene Sulfide with 40% Carbon Fiber Filled
SHC - Specific Heat capacity
TOPSIS - Technique of Order Preference by Similarity to Ideal
Solution
UTS - Ultimate Tensile Strength
YM - Young's Modulus
YS - Yield Strength
xii
LIST OF SYMBOLS
$/kg - Cost per kg
$/m³ - Cost per metre cubic o - Degree oC - Degree celcius
ρ - Density
κe - Electrical conductivity
ρe - Electrical resistivity
GPa - Giga pascal
J/cm - Joule per centimeter
kg/m3 - Kilogram per metre cubic
MPa - Mega pascal
µm/m-°C - Micro meter per meter per celsius degree
µohm-cm - Micro ohm centimeter
N/m - Newtons per metre
N/m2 - Newtons per metre square
Ω⋅m - Ohm metre
Pa - Pascal
% - Percentage
10−6/K - Per million per kelvin
: - Ratio
(Ω⋅m)−1 - Reciprocal of ohm metre
S/m - Siemen per meter
1
CHAPTER 1 INTRODUCTION
1.1 Background
In recent years, new materials are used to replace traditional materials to
achieve weight reduction and performance improvement in engineering application
especially in automotive industry (Rao, 2008). The materials currently used in
automotive industry such as advanced steels, light alloys such as magnesium alloys,
aluminium alloys and titanium alloys, plastics and composites to produce lightweight
vehicles. Design modification, material substitution and efficient manufacturing
process are alternative solutions need to be considered in producing lightweight
vehicles with the increasing demand of improving fuel economy and emission
control. Fuel economy improvement strategies must consider vehicle weight
reduction as the key factor. Several options to achieve significant reduction in
vehicle weight are downsizing of vehicles and reducing the weight of automotive
components using design optimization, parts consolidation and also material
substitution (Mallick, 2010a).
New trends of lightweight vehicles not only can enhance fuel efficiency; the
driving performance improvement can also lower the emissions (Fuchs et al., 2008).
Reducing the weight of vehicle can cause a significant reduction of vehicle power
requirement and hence increase the fuel economy. Studies have shown that every
10% of vehicle weight reduction can cause 5 to 8% greater fuel efficiency (Brooke
and Evans, 2009). Weight reduction of automotive components becomes a new trend
because it can meet the customer expectation in terms of fuel economy, emission
reduction, vehicles safety and performance. Redesigning existing components with
2
lightweight materials is one method to reduce weight in vehicle body construction.
Weight saving in automotive components such as power-train, chassis and
suspension, body panels and body structure might be achieved by using lightweight
materials to replace high density materials like steels (Mayyas et al.,2011).
Material scenario in automotive industry are rapidly changed from cast iron
and low carbon steel towards lighter materials such as polymer matrix composites,
magnesium alloys and aluminium alloys due to greater emphasis on the weight
reduction vehicles. Table 1.1 shows that the materials used in large quantities in
automotive industry are cast iron and low carbon steel as compared to other materials.
Table 1.1: Material distributions in typical automobiles (Mallick, 2010a)
Material Percentage of vehicle weight(%) Main application
Steel 55 Body panels, body structures, engine and transmission components, driveline components, suspension components
Cast iron 9 Engine components, suspension and brakes Aluminium 8.5 Wheel, engine block Copper 1.5 Wiring, electric components Polymers (plastics) and polymer matrix composites
9 Interior components, electric components, fuel line components, under-the hood components
Elastomers 4 Trims, tires, gaskets Glass 3 Glazing Other 10 Fluids, carpes, lubricants
In the last 20 years, many manufacturing processes and new materials have
been developed to decrease the weight of the body panels, body structure, and
suspension components. Existing component weight reduction opportunity in the
body and chassis components is about 60% of a vehicle's weight, engine and
transmission in the Power-train weight is around 25 to 30% of the vehicles weight
(Mallick, 2010a).
An integrated Analytic Hierarchy Process (AHP) and Technique of Order
Preference by Similarity to Ideal Solution (TOPSIS) are the multiple-criteria decision
making problem (MCDM) methods that can be applied in the material selection
decision making process of automotive fender. The AHP method is used to
determine the weight of the selection criteria, while TOPSIS method is used to
3
perform the ranking task and it proposes the best solution among the candidate
materials (Mansor et al., 2014b). This was proven very successfully in many decision
making processes especially involving multiple criteria and alternatives with
attributes need to be analyzed simultaneously to get the best solution. This method
can also apply in other areas that are related to engineering, design and
manufacturing system (Bahraminasabet al., 2014).
The AHP which developed by Saaty in the 1970s (1980) has proven its
efficiency in decision making process and has been widely used in manufacturing
and production systems, business planning, economic planning, conflict resolution,
logistics and capital budgeting (Dweiri& Al-Oqla, 2006). The AHP hierarch model
enables a decision maker to break a complex problem into smaller sub-problems.
Objectives, criteria and sub-criteria are structured from highest level to lowest level
of the model which can help the decision maker to understand more about the
problem. Pair-wise comparison between sub-criteria or alternatives at the same level
with respect to the objectives or criterion of the higher level can reduce the
inconsistencies that possible made by the decision maker. The AHP also helps the
decision makers to evaluate the relative importance of the multiple criteria. The
relative weightage of each criterion tells the decision makers which criterion is the
most important and selects the highest weighted criteria as the best alternatives.
(Mansor et al., 2014b).
Furthermore, Hwang and Yoon (1981) has proposed TOPSIS method for
solving MCDM problem with several alternatives. This method stated that an
alternative which has the shortest distance from the positive ideal solution (PIS) and
the longest distance from the negative ideal solution (NIS) is the most appropriate
alternative. The alternative has the maximum similarity with PIS and minimum
similarity with NIS. PIS maximizes the benefit criteria and minimizes cost criteria,
whereas NIS minimizes the benefit criteria and maximizes the cost criteria. The
TOPSIS method is very useful in material selection decision making process because
it is a quick and easy decision where its ranking output gives a better understanding
of similarities and differences among alternatives (Jahan et al., 2010). TOPSIS has
4
been applied in many multi criteria decision making processes in different
applications such as design selection and process selection.
In this project, integration of AHP and TOPSIS are used in the material
selection process of automotive fender under certain criteria and a wide range of
alternatives. By combining both methods, a more efficient way in analyzing the
decision structure as well as determining the criteria weight can be achieved
especially in dealing with practical and theoretical problem.
1.2 Problem Statement
The materials for the construction of automotive vehicles are rapidly changed
from cast iron and low carbon steel towards lighter materials such as polymer matrix
composites, magnesium alloys and aluminium alloys due to greater emphasis on the
weight reduction vehicles. Most of these lighter materials are used in smaller
quantities in automotive industry in different applications. However, these materials
will be used in larger quantities in future vehicles in order to produce lightweight
vehicles to fulfil fuel economy improvement and reduce environmental pollution.
Material selection is not only affected by weight saving potential, other factors also
need to be considered such as durability, safety, joining, processing, recycling and
cost (Mallick, 2010a). These are the issues need to be considered in material
selection of automotive fender as compared to current used steel fender. Steel
fender's higher density contributes to high vehicle weight, fuel consumption, and
associated energy and greenhouse gas (GHG) footprints. An effective way to choose
the right lightweight material is to tailor with the suitable materials for the
automotive fender as well as to select the best method for the material selection.
Material selection for automotive fender is a multiple-criteria decision making
problem, priority in selecting criteria and candidates for material selection of
automotive fender, are therefore very important. The methodology used in material
selection must be able to solve the multiple-criteria decision making problem.
5
1.3 Objectives
Main objective of the project was to determine the best material for automotive
fender, to specify the objective was as follow:
To identify important criteria in material selection of automotive fender.
To integrate AHP- TOPSIS method in material selection of automotive
fender
1.4 Scopes of Research
The material selection of automotive fender is based on existing design and
manufacturing process of the automotive fender. The material of automotive fender
focuses on lighter materials due to new trend in producing light weight vehicles in
automotive industry. The suitable light weight candidate materials will be selected
based on their performance, cost, service condition and weight requirements in order
to achieve total weight reduction of the vehicle to produce lighter automotive fender.
AHP is a powerful and flexible decision making process as it helps people set
priorities to make the best decision when the both qualitative and quantitative aspects
of a decision need to be considered. Therefore, this project will focus on the
application of integrated AHP and TOPSIS methods in the material selection of
automotive fender.
6
CHAPTER 2 LITERATURE REVIEW
2.0 Overview
This chapter studies about literature review integration of AHP-TOPSIS
method in material selection of automotive fender design. Secondary sources such as
books, journals and online researches are used to get related information regarding
the project. This chapter will provide a understanding about existing materials used
in automotive fender and their related material properties, as well as the method that
is most appropriate for material selection of automotive fender.
2.1 Introduction of Automotive Fender
Fender is a part of exterior body panels of vehicles that located at front and
rear sides of the vehicles body to surround vehicles wheels. Fender is also known as
wing or mudguard. Fender is the panels on the side of the vehicle, right by the door
and over and around the front and rear wheels. Oftentimes they take the shape of the
wheels. Some fenders are integrated into the anatomy of the automobile but some are
stand alone panels which may be bought in dealer shops and installed easily.
Fenders are also designed to avoid wind resistance and make the vehicle
more aerodynamic. Its primary purpose is to prevent sand, mud, rocks, liquids, and
other road spray from being thrown into the air by the rotating tire. It also prevents
other road debris from splashing on and scratching the coat of the vehicle. Fenders
are typically rigid and can be damaged by contact with the road surface. Instead,
7
flexible mud flaps are used close to the ground where contact may be possible as
well as to keep off mud, pebbles,
Fenders of motor vehicles usually are one-piece structures made of sheet
metal that is stamped to shape. In modern motor cars the fenders are of complex
shape, thus requiring expensive, complicated, and relatively huge dies for the
manufacture thereof. Vehicle fenders are subject to hard service, especially in the
winter season when they are splashed with mud and ice, and frequently with salt that
may be used on city streets for melting the snow thereon. Consequently the fenders
usually deteriorate before the other parts of vehicle bodies. Furthermore, the fenders
of vehicles are especially vulnerable to denting such as occurs from collision with
obstructions or other vehicles while the vehicles are being driven or parked. Figure
2.1 shows an automotive fender design.
Figure 2.1: Automotive fender design
2.2 Existing Material Used For Automotive Fender
Fenders are usually made from sheet metal steel as metal provide best
protection during a collision event. Other famous materials used for fenders are
plastics, fibre glass, and carbon fibre. These non-ferrous materials are rust-resistance,
light weight and provide better car design which has advantages over steel. Besides
that, they can sustain damage more readily and easy repairs for small damage.