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DESIGN AND DEVELOPMENT OF
CARBON FIBER DOUBLE WISHBONE SUSPENSION ARM FOR
UTeM FORMULA STYLE RACE CAR
MOHD IZAMUDIN BIN ITAM AHMED
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
I have read this thesis
and from my opinion this thesis
is sufficient in aspect of scope and quality for awarding
Bachelor of Mechanical Engineering (Automotive)
Signature :…….………………………
Supervisor : Muhd Ridzuan bin Mansor
Date :…… ………………………
DESIGN AND DEVELOPMENT OF CARBON FIBER DOUBLE WISHBONE
SUSPENSION ARM FOR UTeM FORMULA STYLE RACE CAR
MOHD IZAMUDIN BIN ITAM AHMED
This report is presented as a requirement for a degree undergraduate in
Bachelor of Mechanical Engineering (Automotive)
Faculty of Mechanical Engineering
Universiti Teknikal Malaysia Melaka
MAY 2010
ii
“I declare this report is on my own work except for summary and quotes that I have
mentioned its sources”
Signature : …………………….
Author : MOHD IZAMUDIN BIN ITAM AHMED
Date : 24th
MAY 2010
iii
To my family
for their support and love.
Together with supports from friends,
honourable teachers and lecturer.
iv
ACKNOWLEDGEMENT
Praise to Allah SWT to who seek help and guidance and under His
benevolence we exist and without His help this project could not have been
accomplished
I would like to take this opportunity to express my gratitude to my supervisor,
Mr. Muhd Ridzuan bin Mansor for his constant guidance and encouragement during
the past one year. He always appreciated whether little progress I have achieved and
continuously give me so much inspiration by sharing his precious knowledge and
experiences. Although there were so many weaknesses in myself, he never shows the
negative attitude and always thinks positive about his student.
Not forgetting, my dedication to the members of the academic and technical
stuffs that continuously support and guiding me directly and indirectly to complete
this project in time. The sharing of experiences helps me to overcome the obstacles
encountered during completing this project
Last but not least, to my family and friends for their supports, praises and
helps all the way during this project being implemented. I really appreciate and
grateful for what they have done. It was their kindness that gave me opportunity to
successfully complete this project.
v
ABSTRACT
The one of most important factors in racing car is weight of car. This can
reduce the performance of the car due to unnecessary weight. This study will reduce
the weight by replacing their suspension system. By choosing current UTeM
Formula Varsity racing car as a reference and FSAE rules as our guidance, a
development of composite suspension has taken place. Most of racing car use double
wishbone suspension link as their suspension system due to its advantages. The
design of this suspension system involved the calculation of load transfer during
cornering and braking condition. Then followed by the force acting on the link
suspension is calculated by using matrix vector unit. After that, the strength of the
composite is calculated by using stiffness matrix equation which it determines the
strength of the composite layers according to its orientation. The value of composite
must greater than value of force acting on the suspension system in order to prevent
failure when it operating in certain condition. Then, the fabrication process of
component will take place using carbon fiber polymer with polyester resin matrix
using conventional hand lay-up technique. Final finished product will undergo
compression testing using INSTRON Universal Testing Machine to determine the
maximum compressive strength.
.
vi
ABSTRAK
Salah satu faktor penting dalam sesebuah kereta lumba adalah berat kereta
tersebut. Keupayaan kereta tersebut akan berkurang disebabkan berat yang
berlebihan. Kajian ini akan mengurangkan berat kereta tersebut dengan
menggantikan sistem suspensinya. Dengan mengambil kereta lumba UTeM Formula
Varsity sebagai contoh dan peraturan FSAE sebagai petunjuk, pembangunan sistem
suspensi berasaskan komposit telah dibuat. Kebanyakkan kereta lumba menggunakan
penyambung suspensi tulang selangka berdasarkan kelebihannya. Rekabentuk sistem
suspensi ini melibatkan pengiraan pemindahan beban ketika dalam keadaan
membelok dan membrek secara mengejut. Diikuti dengan daya yang bertindak
terhadap penyambung suspensi tulang selangka dikira dengan menggunakan
persamaan unit vektor matrik. Kemudian, kekuatan komposit dikira dengan
menggunakan persamaan matrik simpulan yang akan menentukan kekuatan lapisan-
lapisan komposit berdasarkan orientasinya. Nilai komposit mesti melebihi nilai daya
yang bertindak terhadap sistem suspensi supaya dapat mencegah kegagalan semasa
ia sedang beroperasi dalam keadaan tertentu. Kemudian, proses pembuatan
komponen suspensi telah dilakuknn dengan menggunakan serat karbon bersama
resin polyester. Proses ini menggunakan teknik hand lay-up. Hasil daripada proses
tersebut akan digunakan untuk menentukan kekuatan tekanan kritikal dengan
menggunakan mesin ujian universal INSTRON.
vii
CONTENTS
CHAPTER TITLE PAGE
NUMBER
DECLARATION ii
DEDICATION Iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
CONTENTS vii
LIST OF TABLES xii
LIST OF FIGURES xiii
LIST OF APPENDIX xv
CHAPTER 1 INTRODUCTION
1.1 Background Study 1
1.2 Problem Statement 2
1.3 Project Objectives 2
1.4 Project Scope 2
1.5 Project Outline 3
CHAPTER 2 LITERATURE REVIEW
2.1 Overview Suspension System 4
2.2 Types of Suspension System 6
2.2.1 Non-Independent Suspension
System
6
viii
CHAPTER TITLE PAGE
NUMBER
2.2.2 Independent Suspension
System
7
2.2.3 Double Wishbone Suspension
Arm
8
2.2.4 Suspension Geometry 10
2.2.5 Suspension Kinematics/ Load
Transfer
11
2.2.6 Suspension Loading and
Dynamics
13
2.2.6.1 Tire Loads 13
2.2.6.2 Suspension Forces 15
2.3 Composite 16
2.3.1 Fibres 16
2.3.2 Resins 18
2.3.3 Process 20
2.3.3.1 Prepregging Process 20
2.3.3.2 Wet Filament Winding 21
2.3.3.3 Hand Lay-Up of
Prepreg Process
22
2.3.3.4 Automated Tape
Placement Process
23
2.3.3.5 Resin Transfer
Molding
23
2.3.3.6 Pultrusion 24
2.3.3.7 Injection Molding 24
2.3.3.8 Vacuum Bagging,
Autoclave Cure
25
2.3.3.9 Machining Finishing 26
2.4 Joining Technique 26
2.4.1 Mechanical Joining Technique 27
ix
CHAPTER TITLE PAGE
NUMBER
2.4.2 Bonded Joining 27
2.4.2.1 Adhesive Material 27
CHAPTER 3 METHODOLOGY
3.1 Introduction 29
3.2 General Methodology 30
3.3 Load Calculation Methodology 31
3.4 Composite Calculation Methodology 32
3.5 Fabrication Methodology 33
3.6 Methodology Details in PSM 1 34
3.6.1Problem Statement Identification 34
3.6.2 Literature Review 34
3.6.3 Calculation 35
3.7 Methodology Details in PSM 2 36
3.7.1 Fabrication Process 36
3.7.2 Testing 36
3.7.3 Discussion and Conclusion 36
3.8 Suspension Design 37
3.8.1 Concept Design 37
3.9 Introduction to Calculation Theory 40
3.10 Members Nomenclature 41
3.11 Suspension Link Calculation 43
3.12 Composite Laminate Analysis 46
3.13 Introduction to Fabrication Process 47
3.14 Fabrication of Suspension
Component
48
3.14.1 Preparation before
Component Fabrication
48
3.14.2 1st Stage Component
Fabrication (Lay-Up)
51
x
CHAPTER TITLE PAGE
NUMBER
3.14.3 2nd
Stage Component
Fabrication
54
3.15 Construction of Testing Jig 56
3.16 Compression Test for Composite
Suspension
58
3.16.1 Compression Test for
Composite Suspension in
Longitudinal Direction
59
3.16.2 Compression Test for
Composite Suspension in
Lateral Direction
60
CHAPTER 4 RESULT AND DISCUSSION
4.1 Introduction 61
4.2 Suspension Members Calculation 62
4.3 Composite Calculation Analysis 64
4.4 Calculation Theory Summary 65
4.5 Experimental Result 66
4.6 Discussion 69
CHAPTER 5 CONCLUSION
5.1 Conclusion 71
5.2 Recommendation 72
REFERENCE 73
APPENDICES 75
xi
LIST OF TABLES
NO. TITLE PAGE
NUMBER
2.1 Double Wishbone Arrangement (Mark Wan, 1998-
2000)
9
6.1 Suspension Labelling Coordinate Points 62
6.2 Wheel Centre Loading for Front Right Corner of
the Suspension (Borg, 2009)
63
6.3 Wheel Centre Loading for Front Right Corner of
the Suspension
64
xii
LIST OF FIGURES
NO. TITLE PAGE
NUMBER
2.1 De Dion Axle Suspension System (Mark Wan,
1998-2000)
7
2.2 Double Wishbone Suspension System (Longhurst,
2006)
8
2.3 Suspension Geometry Factors (Milliken, 1995) 10
2.4 Variable and Dimension Associated with lateral
Load Transfer (Milliken, 1995)
12
2.5 Calspan TIRF Tire Measurement Machine (Borg,
2009)
13
2.6 Tire Contact Patch under Slip Angle and Effects of
Pneumatic Trails (Gillepsie, 1992)
14
2.7 Example Graph of Lateral Force versus Vertical
Load (Milliken, 1995)
14
2.8 Prepregging Schematic (Milauskas, 2010) 20
2.9 Filament Winding Schematic (Milauskas, 2010) 21
2.10 Hand Lay-Up of Prepreg (Milauskas, 2010) 21
2.11 Automated Tape Placement (Milauskas, 2010) 22
2.12 Resin Transfer Molding (Milauskas, 2010) 23
2.13 Pultrusion Processing (Milauskas, 2010) 23
2.14 Injection Molding (Milauskas, 2010) 24
2.15 Vacuum Bagged Part Place in Autoclave for Cure
(Milauskas, 2010)
25
2.16 Example of Adhesive Use In This Project 28
3.1 General Methodology 30
xiii
NO. TITLE PAGE
NUMBER
3.2 Load Calculation Methodology 31
3.3 Composite Calculation Methodology 33
3.4 Fabrication Methodology 33
3.5 Aerodynamic Drag Coefficient
(www.ceepo.com, 2010)
37
3.6 Final Design of Upper Arm Wishbone Suspension 38
3.7 Engineering Drawing for Upper Arm Wishbone
Suspension
39
3.8 SAE Car Coordinate System (Gillespie, 1992) 40
3.9 3D Graphic Modelling for Front Right Suspension
Assembly with Point Label
42
3.10 Mould made from box for Lower Arm 48
3.11 Grinded Metallic Ball Joint 49
3.12 Carbon Fiber Woven Roving 49
3.13 Mold Release Wax 50
3.14 Mold Release Wax Being Applied 50
3.15 Hardener Being Added At Ratio 99:1 into Setup
Resin
51
3.16 The First 4 Plies Applied To the Mold with Matrix
Resin
51
3.17 The Metallic Ball Joint Has Been Positioned 52
3.18 Finished Lay-Up Component Consist Metallic Ball
Joint and Eight (8) Plies of Carbon Fiber
52
3.19 The Component Already Cured 53
3.20 Trimming Process Using Grinder (The Box Will
Remove When We Get Necessary Shape after
Trimming)
54
3.21 Our Final Product after Trimming Process 54
3.22 Adhesive Been Applied To Metallic Ball Joint 55
xiv
NO. TITLE PAGE
NUMBER
3.23 Mild Steel Rectangular Have Been Cut Into Needed
Dimension
56
3.24 The Jig Members Being Welded According To
Specification
56
3.25 50% Complete Jig Construction 57
3.26 Composite Wishbone Assemble Together With Its
Testing Jig
57
3.27 Assembled Composite Wishbone Has Been Placed
In INSTRON Universal Testing Machine
59
3.28 Buckling Behaviour on Composite Wishbone 59
3.29 Upper Arm Has Been Placed in Lateral Direction 60
3.30 Buckling Behavior in Lateral Direction 60
6.1 Stress – Strain Graph for Composite Wishbone -
Upper Arm in Longitudinal Direction
66
6.2 Stress – Strain Graph for Composite Wishbone -
Lower Arm in Longitudinal Direction
66
6.3 Stress – Strain Graph for Composite Wishbone -
Upper Arm in Lateral Direction
67
6.4 Stress – Strain Graph for Composite Wishbone -
Lower Arm in Lateral Direction
67
6.5 Failure Component from Compression Test 68
xv
LIST OF APPENDIX
NO. TITLE PAGE
NUMBER
A Current Design on UTeM Formula Varsity Race
Car
75
B Full Result of Suspension Link Calculation 77
C Composite Properties 78
D The Assembly Design of Double Wishbone
Suspension Arms
79
E Detail Drawings of Double Wishbone Suspension
Arms
80
F LOCTITE Adhesive 81
G Gantt Charts for PSM 1 & PSM 2 82
1
CHAPTER 1
INTRODUCTION
1.1 Background Study
The objective of this study is to design and develop a racing car suspension
system based on composite materials. The main goal is to decrease the weight of
suspension but in the same time, it provides strength beyond metallic material.
In recent event, Universiti Teknikal Malaysia Melaka has participated in the
Formula Varsity race event and secured second place during the competition.
Improvements on the vehicle were later carried out in order to sustain the good
performance and achieve better results for similar future races.
Suspension is one of important part in vehicle. The main purpose of
suspension is to absorb vibration and impacts come from road profile due to load
transfer and extreme manoeuvres. Sneaking into race car world, the suspension will
hold the tyres to its maximum area contact with road profile in order to maximize its
grip. The suspension design also affects the chamber gain in tyres and further
information will explain in Chapter 2.
In over 40 years, carbon fiber polymer has been proven for its weight and
stiffness in various fields. By expecting that our racing car weight will decrease by
replacing their metal suspension with composite suspension, this study has taken
their place.
2
1.2 Problem Statement
The current UTeM racing car used double wishbone suspension arm built
from mild steel and it can affect the weight of vehicle. In addition, according to the
racing team, they do not have conducted any strength analysis regarding the vehicle
in extreme manoeuvre in racing circuit.
Therefore, in order to make new improvement and overcome this problem, a
study about racing car suspension has been carry away and it involving composite
material. Carbon fiber polymer has proven for it strength beyond the steel and
provide less weight. By apply this fact; the study about racing car suspension in
composite form has taken place.
1.3 Project Objective
The main purpose of this project is to design and develop the suspension arm
for UTeM Formula Style Racing Car using carbon fiber polymer composite.
1.4 Project Scope
This study focuses on new composite racing car suspension. Before
composite laminate analysis can be undergo, the analysis on load acting must done
following the UTeM 2nd
Formula Varsity Regulation and International FSAE Racing
Event. Thus, the analysis has taken place.
In short the project scope is listed as follow:
i. To calculate the load acting on the component during operation.
ii. To perform composite laminate analysis.
iii. To produce detail design of the component using 3D CAD software.
iv. To fabricate the component using carbon fiber-polyester matrix.
v. To perform compression test and evaluate the component performance.
3
1.5 Project Outline
This report on “Design and Development Carbon Fiber Double Wishbone
Suspension Arm for UTeM Formula Style Race Car” is divided into several chapters.
Chapter 1 introduces the audience to the general background of this research, the
problem statement, project objectives, as well as the project scope. Also, it offers an
overall view of the project outline.
Chapter 2 is a literature reviews and background study gathered from
electronic media, published journals, and books. This chapter will elaborate about
this project briefly.
Chapter 3 explains about the methodology used in this project pictured as
flow chart along with explanation of every stage process. This chapter also explains
the theoretical calculation of load acting on component followed by composite
laminate analysis calculation along with the new double wishbone suspension design.
The fabrication process along with components fabrication using carbon fiber and
polyester matrix as resin including the design of testing jig and its fabrication process
will be included in this chapter In addition; the testing procedure also will be
explained in this chapter.
Chapter 4 indicates the results of the calculation and compared with actual
value (experimental data). This chapter also will discuss on the difference of the
value obtained in this project with previous researcher.
Finally, Chapter 5 will present the conclusion and suggestion in upgrading
the project for a better performance in future.
4
CHAPTER 2
LITERATURE REVIEW
2.1 Overview Suspension System
The main functions of a vehicle’s suspension systems are to isolate the
structure and the occupants from shocks and vibrations generated by the road surface.
The suspension systems basically consist of all the elements that provide the
connection between the tires and the vehicle body. According to Gillepsie (1992), the
primary functions for suspension systems are;
Provide vertical compliance so the wheels can follow the uneven road,
isolating the chassis from roughness in the road.
Maintain the wheels in the proper steer and camber attitudes to the road
surface.
React to the control forces produced by the tires-longitudinal (acceleration
and braking) forces, lateral (cornering) forces, and braking and driving
torques.
Resist roll of the chassis.
Keep the tires in contact with the road with minimal load variations
To accomplish all functions, the suspension system requires an elastic
resistance to absorb the road shocks and this job is fulfilled by the suspension springs.
Various different types of springs have been used in vehicle suspensions such as leaf
springs, helical coil springs, torsion bar springs, air springs, rubber springs. It is
obvious that a suspension system must be able to withstand the loads acting on it.
5
These forces may be in the longitudinal direction such as acceleration and braking
forces, in the lateral direction such as cornering forces, and in the vertical direction.
This chapter consists of three main sections. In the first section, the types of
suspension systems are introduced and the advantages of double wishbone
suspension system are presented. In the second section, vehicle dynamics and
suspension kinematics are presented under different cases in order to obtain axial
loads on the double wishbone suspension links.
6
2.2 Types of Suspension System
Suspensions basically can be identify into two main groups-non-independent
and independent suspensions. Each group carried different functions and therefore,
this differentiation will be discussed generally in this chapter.
2.2.1 Non-Independent Suspension System
In non-independent suspension systems (known as solid axle suspension
system), wheels are mounted at the ends of a rigid beam so that any movement of
one wheel is transmitted to the opposite wheel causing them to steer and camber
together.
Solid drive axles are used on the rear of many cars and most trucks and on the
front of many four-wheel-drive trucks. Solid beam (non-driven) axles are commonly
used on the front of heavy trucks where high load-carrying capacity is required.
These types of suspension have the advantage that wheel camber is not
affected by body roll. Thus there is little wheel camber in cornering, except for that
which arises from slightly greater compression of the tires on the outside of the turn.
In addition, wheel alignment is readily maintained, minimizing tire wear. It also
claimed to be cheaper than independent suspension. The major disadvantage of non-
independent suspension system is their bad ride quality, and both wheel chambered
on bump which we want to reduce in Formula Varsity Race. The most common solid
axles are Hotchkiss, Four link and De Dion (Figure 2.1).
7
Figure 2.1: De Dion Axle Suspension System (Mark Wan, 1998-2000)
2.2.2 Independent Suspension System
In contrast to non-independent suspension system, independent suspensions
allow each wheel to move vertically without affecting the opposite wheel. Nearly all
passenger cars and light trucks use independent front suspensions, because of the
advantages in providing room for the engine and the better resistance to steering
vibrations. The independent suspension also has the advantage that it provides
inherently higher roll stiffness relative to the vertical spring rate. Further advantages
include easy control of the roll centre by choice of the geometry of the control arms,
larger suspension deflections, ideal chamber control and greater roll stiffness for a
given suspension vertical rate.
Over the years, many types of independent front suspension have been tried
such as Mac Pherson, Trailing arm, Swing axle, Torsion Beam, Multi link and
Double Wishbone suspension (Figure 2.2). Many of them have been discarded for a
variety of reasons, with only two basic concepts, the double wishbone and the
Macpherson strut, finding widespread success in many varied forms.
