UNIVERSITI TEKNIKAL MALAYSIA MELAKA OPTIMIZATION OF THE UTEM FV MALAYSIA RACE CAR SUSPENSION SYSTEM DESIGN TO REDUCE ROLLING EFFECT This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Engineering Technology (Automotive Technology) (Hons.) by MOHD FIRDAUS BIN JUHARI B071210560 911116-10-5777 FACULTY OF ENGINEERING TECHNOLOGY 2015
UNIVERSITI TEKNIKAL MALAYSIA MELAKA BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA TAJUK: OPTIMIZATION OF THE UTEM FV MALAYSIA RACE CAR SUSPENSION SYSTEM DESIGN TO REDUCE ROLLING EFFECT SESI PENGAJIAN: 2014/15 Semester 2 Saya MOHD FIRDAUS BIN JUHARI 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 (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972) TIDAK TERHAD Disahkan oleh: (TANDATANGAN PENULIS) (TANDATANGAN PENYELIA) Alamat Tetap: 76 F-3, Kg Puah Cop Rasmi: Jalan Gombak, 53000 Kuala Lumpur, ** 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.
FAKULTI TEKNOLOGI KEJURUTERAAN Tel : +606 234 6623 Faks : +606 23406526 Rujukan Kami (Our Ref) : Rujukan Tuan (Your Ref) : Pustakawan Perpustakaan UTeM Universiti Teknikal Malaysia Melaka Hang Tuah Jaya, 76100 Durian Tunggal, Melaka. 28 JAN 2015 Tuan/Puan, PENGKELASAN LAPORAN PSM SEBAGAI SULIT/TERHAD LAPORAN PROJEK SARJANA MUDA TEKNOLOGI KEJURUTERAAN PEMBUATAN (COURSE NAME): MOHD FIRDAUS BIN JUHARI Sukacita dimaklumkan bahawa Laporan PSM yang tersebut di atas bertajuk OPTIMIZATION OF THE UTEM FV MALAYSIA RACE CAR SUSPENSION SYSTEM DESIGN TO REDUCE ROLLING EFFECT mohon dikelaskan sebagai *SULIT / TERHAD untuk tempoh LIMA (5) tahun dari tarikh surat ini. 2. Hal ini adalah kerana IANYA MERUPAKAN PROJEK YANG DITAJA OLEH SYARIKAT LUAR DAN HASIL KAJIANNYA ADALAH SULIT. Sekian dimaklumkan. Terima kasih. Yang benar, Tandatangan dan Cop Penyelia * Potong yang tidak berkenaan NOTA: BORANG INI HANYA DIISI JIKA DIKLASIFIKASIKAN SEBAGAI SULIT DAN TERHAD. JIKA LAPORAN DIKELASKAN SEBAGAI TIDAK TERHAD, MAKA BORANG INI TIDAK PERLU DISERTAKAN DALAM LAPORAN PSM.
DECLARATION I hereby, declared this report entitled Optimization of the UTeM FV Malaysia Race Car Suspension System Design to Reduce Rolling Effect is the results of my own research except as cited in references. Signature Name : : MOHD FIRDAUS BIN JUHARI Date : 10 DECEMBER 2015 iv
APPROVAL This report is submitted to the Faculty of Engineering Technology of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Engineering Technology (Automotive Technology) (Hons.). The member of the supervisory is as follow:. (Mr Nor Azazi bin Ngatiman) v
ABSTRACT One of the most important factors that affect the performance of the racing cars are the behaviour and responses of the car suspension. Rolling can reduce the performance of the car due to unnecessary motion that occur such as rolling. This study will help to improve the suspensions of the UTeM FV Malaysia race car so that the car will experience more confidents handling especially while enter and exit from the corner by doing some improvements on the rolling centre of the suspensions. By using current UTeM FV Malaysia racing car as a reference and FSAE rules as our guidance, an improvement on suspension has taken place using related CAD software through simulation. Most of racing car use double wishbone suspension link as their suspension system due to its advantages. The current suspension design is analysed using Altair Multi Body Dynamic Motion View, and the result will be used for optimization. In conclusion, the result from optimization must be better compared to existing to ensure the objective to reduce rolling on the car is achieved. vi
ABSTRAK Salah satu faktor penting yang perlu diambil kira dalam memastikan prestasi kereta lumba dalam keadaan yang terbaik adalah kelakuan atau tindakbalas sistem gantungan kereta tersebut ketika dipandu. Ini sangat menyumbang kepada penurunan prestasi kereta lumba dengan kehadiran pergerakan yang tidak diperlukan seperti gulingan. Kajian ini akan membantu untuk meningkatkan lagi kebolehan sistem gantungan kereta lumba UTeM FV Malaysia untuk menahan kesan gulingan ketika mengambil selekoh dengan melakukan pengubahsuaian pada roll centre sistem gantungan. Kereta lumba sedia ada UTeM akan digunakan sebagai rujukan dan peraturan oleh FSAE dijadikan sebagai petunjuk dalam melakukan penaiktarafan ini yang dijalankan secara simulasi oleh perisian CAD yang berkenaan. Kebanyakan kereta lumba menggunakan sistem gantungan jenis Double Wishbone disebabkan oleh kelebihan-kelebihan yang dimiliki olehnya. Sistem gantungan semasa akan dianalisis menggunakan perisian Altair Multi Body Dynamic Motion View, dan keputusan analisis akan dijadikan panduan untuk melakukan penaiktarafan. Kesimpulannya, keputusan daripada penambahbaikan yang dibuat perlulah lebih baik berbanding keputusan sistem gantungan sedia ada supaya objektif untuk mengurangkan kadar gulingan itu dapat dicapai. vii
DEDICATIONS This thesis is dedicated to my parents for their love, support and encouragement. And to my Supervisor, Mr Nor Azazi Bin Ngatiman for has been my constant source of knowledge and inspiration. viii
ACKNOWLEDGMENTS 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 Nor Azazi Bin Ngatiman for his support, guidance and constant guidance. All appreciation from him has motivate me so much and thanks for all of the precious knowledge and experience that have been shared. And million thanks to Madam Nor Hamizah Binti Miswan for all the guides and support also for all the knowledge that had been shared. Special dedication also to the members of the academic and technical staffs that continuously support and guiding me directly and indirectly to complete this project within the time. The sharing of experiences helps me to overcome the obstacles encountered during completing this project Last but not least, to my lovely family and friends for the non-stop supports, motivates and helps all the way during this project being implemented. Big appreciation and grateful for them. Thank you also to those indirectly supporting me to complete this project. May Allah SWT bless be with us. ix
TABLE OF CONTENTS DECLARATION... iv APPROVAL... v ABSTRACT... vi ABSTRAK... vii DEDICATIONS... viii ACKNOWLEDGMENTS... ix TABLE OF CONTENTS... x LIST OF FIGURES... xv LIST OF TABLE... xvi LIST OF SYMBOLS AND ABBREVIATIONS... xvii CHAPTER 1 : INTRODUCTION... 1 1.0 Introduction... 1 1.1 Background... 1 1.2 Classification of Suspension System... 2 1.2.1 Double Wishbone... 3 1.2.2 MacPherson Strut... 3 1.3 Problem Statement... 4 1.4 Objective... 5 1.5 Scope... 5 CHAPTER 2 : LITERATURE REVIEW... 6 x
2.1 Introduction... 6 2.2 History... 6 2.3 Suspension Fundamental... 7 2.3.1 Unsprung weight... 7 2.3.2 Sprung weight... 7 2.3.3 Wheelbase... 7 2.3.4 Wheel track... 8 2.3.5 Center of gravity... 8 2.3.6 Mass centroid axis... 8 2.3.7 Roll center... 9 2.3.8 Camber... 10 2.3.9 Caster... 11 2.3.10 Toe... 12 2.3.11 Kingpin... 12 2.3.12 Scrub radius... 13 2.3.13 Dive and squat... 14 2.4 Function of Suspension... 14 2.5 Springs... 16 2.5.1 Springs Terminology... 17 2.5.2 Coil Spring... 17 2.5.3 Leaf Spring... 18 2.6 Shock Absorbers... 18 2.6.1 Oil filled shock absorber... 19 xi
2.6.2 Gas charged shock absorber... 19 2.6.3 Reservoir shock absorber... 20 2.7 Type of Suspension System... 20 2.7.1 Solid Axle Suspension... 20 2.7.2 Independent Suspension... 21 2.7.2.1 MacPherson Strut... 22 2.7.2.2 Multi-link Suspension... 23 2.7.2.3 Double Wishbone... 24 2.8 Formula SAE Race Car Suspensions... 26 2.9 Multi Body Dynamics... 27 CHAPTER 3 : METHODOLOGY... 29 3.1 Introduction... 29 3.2 Execution of Project... 29 3.2.1 Identification of FV rules and regulations... 29 3.2.2 Modelling and analysis parameter... 29 3.3 Design flowchart... 30 3.4 Identification of relevant Formula Varsity rules... 31 3.4.1 Suspensions... 31 3.4.2 Track width... 31 3.4.3 Wheelbase... 31 3.5 Modelling and analysis parameters... 32 3.6 Suspension modelling... 32 3.7 Analysis... 36 xii
3.8 UTeM FV Race Car in Motion View... 37 CHAPTER 4 : RESULT AND DISCUSSION... 38 4.1 Introduction... 38 4.2 Modelling the Suspensions... 38 4.3 Trial results... 39 4.3.1 Upper ball joint adjustment... 39 4.3.1.1 First run... 39 4.3.1.2 Second run... 40 4.3.1.3 Third run... 41 4.3.2 Tie rod end adjustment... 41 4.3.2.1 First run... 42 4.3.2.2 Second trial... 42 4.3.2.3 Third trial... 43 4.4 Optimized Suspension Design... 44 4.5 Comparison of Results... 45 CHAPTER 5 : CONCLUSION... 50 5.0 Introduction... 50 5.1 Summary of Research... 50 5.2 Achievement of Research Objectives... 50 5.3 Significance of Research... 51 5.4 Problems Faced During Research... 51 5.5 Suggestion for Future Work... 51 APPENDIX A... 52 xiii
REFERENCES... 56 xiv
LIST OF FIGURES Figure 1.1: Example of race car Double Wishbone (Akhmadeen, 2008).... 3 Figure 2.1: Determination of roll centre and moment arm (Farrington, 2011).... 9 Figure 2.2: Camber in relation to slip angle (Christiansen, 2012).... 10 Figure 2.3: Camber angle (Iman, Esfahani, & Mosayebi, 2010).... 11 Figure 2.4: Caster angle and caster offset (Farrington, 2011)... 11 Figure 2.5: Toe and angle setting (Farrington, 2011).... 12 Figure 2.6: Kingpin axis (Sh. et al., 2010)... 13 Figure 2.7: Scrub radius (Christiansen, 2012).... 14 Figure 2.8: Shows the car suspension allowing the tire to road contact under various condition (Hadi, 2007).... 15 Figure 2.9: Types of coil spring (Popa, 2005).... 17 Figure 2.10: Leaf spring (Popa, 2005)... 18 Figure 2.11: Types of shock absorber (Popa, 2005)... 19 Figure 2.12: Solid axle suspension; a) front view and b) side view (Sh. et al., 2010).... 21 Figure 2.13: The independent suspension system (Sh. et al., 2010)... 21 Figure 2.14: Mechanism of MacPherson Strut (Thacker & Bhatt, 2014)... 22 Figure 2.15: Multi-link suspension geometry (Johansson, 2011)... 24 Figure 2.16: Mechanism of Double Wishbone.... 24 Figure 2.17: Double Wishbone parts (Thacker & Bhatt, 2014).... 25 Figure 2.18: Example of general MBD model of suspensions.... 28 Figure 3.1: General suspension model on static roll analysis.... 37 Figure 4.1: Roll center height vs Roll angle... 39 Figure 4.2: Roll center height vs Roll angle... 40 Figure 4.3: Roll center height vs Roll angle... 41 Figure 4.4: Roll center height vs Roll angle... 42 Figure 4.5: Roll center height vs Roll angle... 43 Figure 4.6: Roll center height vs Roll angle... 44 Figure 4.7: Roll center height vs Roll angle... 45 Figure 4.8: Roll center height vs Roll angle... 46 Figure 4.9: Roll center lateral vs Roll angle... 47 Figure 4.10: Suspension roll rate vs Roll angle... 47 Figure 4.11: Total roll rate vs Roll angle... 48 xv
LIST OF TABLE Table 1: Actual parameter of FV suspension system... 33 Table 2: First trial for upper ball joint.... 34 Table 3: Second trial for upper ball joint.... 34 Table 4: Third trial for upper ball joint.... 35 Table 5: First trial for outer tie rod.... 35 Table 6: Second trial for outer tie rod... 35 Table 7: Third trial for outer tie rod.... 36 Table 8: Vehicle parameter... 37 Table 9: Roll center height comparison... 46 Table 10: Result comparison... 49 xvi
LIST OF SYMBOLS AND ABBREVIATIONS FSAE = Formula SAE(Society of Automotive Engineer) FV = Formula Varsity SLA = Short-Long Arm CAD = Computer Aided Design CG = Center of Gravity MBD = Multi Body Dynamic KPI = Kingpin Inclination UBJ = Upper Ball Joint LBJ = Lower Ball Joint OTRB = Outer Tie Rod Ball Joint xvii
CHAPTER 1 INTRODUCTION 1.0 Introduction This chapter covers all the informations of the thesis starting from the background of the project, problem statement, objective and scope. 1.1 Background Suspension system in race car is one of the most crucial part in which it will influence the performance of the car and provide rigidity, stability and speed while entering and exit from corner or in straight run. The suspension system consists of springs, shock absorber, struts, control arms and spindle or axle as well as the bushing that allow the necessary motions. These parts should hold the tire firmly and wheel in correct alignment with the car and the road. The suspension is the main mechanisms that separates the bump between vehicles and the roads. It also the device connecting the body with wheels. Irrelative motion on the body between the wheels, the motion is constrained by the suspension. In fact, all forces, moment exerted between the wheels and the ground passing through the suspension (Sun, Deng, & Zhang, 2014). In other meaning, suspension system is a mechanism that physically separates the sprung mass (car body) from the unsprung mass (car wheel). Vehicle suspension system main function is to provide minimum vertical acceleration transmitted to the passenger which directly provides road comfort. Also to prevent the vehicles to experience extreme body rolling, pitching and yawing. An excessive wheel travel will result in non-optimum behaviour of tyre to the road that will lead to poor adhesion and handling. Besides that, to maintain good vehicle handling, the optimum tyre to road contact must be maintained on all wheels. (Hadi, 2007) 1
Load disturbances include the variation of loads induced by accelerating, braking and cornering. Therefore, a good suspension design is concerned with disturbance rejection to the outputs. Roughly speaking, a conventional suspension needs to be soft to insulate against road disturbances and hard to insulate against load disturbances. This make a suspension design is an art of compromise between these two goals (Wang 2001). Therefore, design of the suspension system is an important part of the overall vehicle design, which determines the performance of the racing car (Sun et al., 2014). 1.2 Classification of Suspension System Suspension system have variety of type and designs which each of the design have their own advantages and disadvantages. There are two main categories of suspension system; i. Dependent suspension (i.e. Rigid axle, semi rigid axle, trailing arm) ii. Independent suspension (i.e. Macpherson, Double wishbone, Multilink) For dependent suspension system, the motion of a wheel on one side is dependent on the motion of wheel on the other side. When one wheel of the vehicle strikes a pothole, the effect is transmitted directly to wheel on the other side. This has a harmful effect on ride and handling of the vehicle. With independent suspension system, the motion of wheel is independent of the other wheel, so that a disturbance at one wheel is not effecting to a wheel on the other side. This leads to better ride and handling capabilities. Among all the design, there is two popular design that been used by the car manufacturer that is Double Wishbone Suspension and MacPherson Strut. Both of this suspension is regularly can be seen on vehicles suspension system due to its performance (Sh., J., N., a., & R., 2010). 2
1.2.1 Double Wishbone The most common design for the front suspension of American car following World War II used two lateral control arms to hold the wheel. Each wishbone has two mounting points to the chassis and one joint at the knuckle. The shock absorber and coil spring mount to the wishbones to control vertical movement. Design of the geometry for a SLA requires careful refinement to give good performance. The camber geometry of an unequal-arm system can improve camber at the outside wheel by counteracting camber due to body roll, but usually carries with it less-favourable camber at the inside wheel (equal-length parallel arms eliminate the unfavourable condition on the inside wheel but at the loss of camber compensation on the outside wheel). At the same time, the geometry must be selected to minimize tread change to avoid excessive tire wear. The compact design of a coil spring makes it ideal for use in front suspension systems (Güler, 2006). Figure 1.1: Example of race car Double Wishbone (Akhmadeen, 2008). 1.2.2 MacPherson Strut It was created by Earl Macpherson in 1949 for the ford company. Due to its light weight and size compatibility this kind of suspension is widely used in different vehicles. Moreover this kind of vehicle is more popular to be found in the front of the 3
car even though it was also used as a rear suspension. This system is uses the axis of a telescopic damper as the upper steering pivot. It is widely used in modern vehicles. MacPherson struts consist of a wishbone or a substantial compression link stabilized by a secondary link which provides a bottom mounting point for the hub or axle of the wheel (Purushotham, 2013). 1.3 Problem Statement Suspension has become the big issues now when it comes to car performance. Whether the car is for road use or track use, suspension always become the main things to be discussed. For road use, the comfort of the suspension always be the priority. Different things happened for track used, the vehicle must be able to keep the maximum tire to road contact while in and out from cornering, braking and accelerating which the result will minimizing the comfort. In this research, the student is responsible to study and improve the design of the suspension system for UTeM FV Malaysia race car. For beginning, overview on current UTeM FV Malaysia race car will help to look for the optimization and redesign opportunities to obtain better quality of suspension design, which will result in better ride and handling also rolling effects. The design should meet the technical performance and safety for the driver and car. The designed suspension system will be analysed virtually using related CAD software. The aim is the suspension system is fit enough in term of quality and safety, and will reduce the rolling on the vehicles while cornering which can enhance the car performance. 4
1.4 Objective In this project, the objectives of the research are as follows: 1. To analyse the suspension system of UTeM FV Malaysia race car by simulation using related CAD software. 2. To optimize the design of Double Wishbone suspension for UTeM FV Malaysia race car to reduce rolling effect. 1.5 Scope To achieve the objective of this project, analysis is focused on following scope: 1. This project will focus on Double Wishbone suspension system. 2. The CAD software that is used to generate the design is Hyperwork by using Multi Body Dynamic (MBD). Analysis also will be done using Hyperwork. 3. Current design of Double Wishbone suspension system on FV Malaysia car is improved in order to obtain optimum performance subject to rolling effect of the car. 5
CHAPTER 2 LITERATURE REVIEW 2.1 Introduction In the literature review the primary functions of the suspension systems in vehicles and their effect in ride and handling are discussed. A dynamic simulation software is reviewed through this chapter. Finally the effective techniques to reduce the rolling effect of the car are discussed. 2.2 History Early stage of transportation required suspension of some kind. With the limited technology at that time, simple wrought-iron beam springs were combined in several layers to obtain the required combination of compliance with strength. These design became known simply as leaf springs. To increase the compliance, a pair of leaf springs were mounted back-to-back. They were curved, and so then known as elliptical springs. Single ones were called semi-elliptic. (Dixon, 2009) In early age of road transportation, leaf springs is the most practical design of suspension ever had at that time. At the front, the leaf spring was not bring satisfaction to the driver, because of the effects in steering geometry difficulties (bump steer, roll steer, brake wind-up steering effects, and shimmy vibration problems). In 1920s, the rigid axle at the front was increase in problem. With increasing engine power and vehicle speeds, this was becoming increasingly dangerous. Hard front springs were used to solve the problem. It is limiting the axle movement, but this results in very poor ride comfort and allowing much softer springs and greater 6
comfort. Around 1930, Sloan considered the problem of ride quality as one of the most important and most crucial in automotive engineering, and the problem was getting worse as car speeds increased. By 1933 Rolls-Royce already had an independent front suspension. After that, most vehicles started using hydraulic shock absorbers and balloon (low-pressure) tyres (Dixon, 2009). 2.3 Suspension Fundamental 2.3.1 Unsprung weight The unsprung weight of a vehicle is the fraction of the total weight that is not supported by the suspension springs and will usually consist of the wheels, tires, hubs, hub carriers, brakes (if mounted outside the car s chassis), and lastly, roughly 50% of the weight due to drive shafts, springs and shocks as well as the suspension links (Farrington, 2011). 2.3.2 Sprung weight This is basically the opposite of the mentioned definition above. Sprung weight is the portion of total car weight which is supported by the suspension springs. This weight is much larger than the unsprung weight as it consists of weight from the majority of car components which would include the chassis, engine, driver, fuel, gearbox and other components housed in the chassis (Farrington, 2011). 2.3.3 Wheelbase Wheelbase is defined as the distance between the front and rear axle centrelines. It also influences weight transfer, but in the longitudinal direction. Large wheelbase will experience less pitch motion and short wheelbase is effective in 7