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.

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: _______________________

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

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)

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.

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.

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.

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

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

2.3.4 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

4.1 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

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

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

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

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

LIST OF SYMBOLS

$/kg - Cost per kg

$/m³ - Cost per metre cubic

o _{- Degree}

o_{C - 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

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

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 _{vehicle weight(%)} Percentage of 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

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

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.

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.

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,

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.

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 _{vehicle weight(%)} Percentage of 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

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

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.

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.

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,

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.