DESIGN OF FORMULA STUDENT RACE CAR CHASSIS
UNDERGRADUATE RESEARCH PROJECT REPORT
Submitted by
ALPEREN KALE
MECHANICAL ENGINEERING DEPARTMENT
HACETTEPE UNIVERSITY
JUNE 2016
ABSTRACT In this undergraduate research project report, fundamental approach to Formula Student race car chassis design is discussed. The most convenient chassis types, materials and production methods are gathered from literature and represented. Also by considering Formula Student regulation, it is analyzed that how a Formula Student race car chassis must be designed. This report is mainly constructed of basic approaches and easy methods for first year teams.
ACKNOWLEDGEMENTS Firstly, I would like to state my appreciation to my supervisor Assist.Prof.Dr.-Ing. Okan Görtan, for his worthful contribution to complete this project successfully. Furthermore, I would like to thank to all of our department’s academic and other staff, rectorship and Hacettepe Technopolis for their support to Formula Student project. And also I want to use this opportunity to thank the Hacettepe University Mechanical Engineering Department for the education which I have taken and international experience.
Finally I have to thank to all my team mates which we are worked together day-and-night.
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TABLE OF CONTENTS
1.
INTRODUCTION ................................................................................................................. 4
2.
LITERATURE REVIEW ...................................................................................................... 5 2.1.
Definition and History ................................................................................................... 5
2.2.
Chassis Types ................................................................................................................. 6
2.2.1.
Ladder Chassis ........................................................................................................... 6
2.2.2.
Self-Support Chassis .................................................................................................. 7
2.2.3.
Space Frame Chassis .................................................................................................. 8
2.2.4.
Monocoque Chassis.................................................................................................... 9
2.3. 3.
4.
MATERIALS FOR CHASSIS COMPONENTS ................................................................ 10 3.1.
Steel.............................................................................................................................. 10
3.2.
Aluminum .................................................................................................................... 11
3.3.
Composites ................................................................................................................... 11
3.4.
Material Selection Criteria ........................................................................................... 12
PRODUCTION METHODS ............................................................................................... 14 4.1.
Mechanical Joint .......................................................................................................... 14
4.2.
Welding ........................................................................................................................ 14
4.2.1.
Stick / Arc Welding .................................................................................................. 15
4.2.2.
MIG Welding ........................................................................................................... 15
4.2.3.
TIG Welding ............................................................................................................ 16
4.3. 5.
Comparison of Chassis Types ........................................................................................ 9
Hybrid Chassis ............................................................................................................. 16
DESIGN .............................................................................................................................. 17 5.1.
Design Overview ......................................................................................................... 17
5.2.
CAD Design ................................................................................................................. 18 2
5.3.
Analysis Methods ......................................................................................................... 20
6.
CONCLUSION ................................................................................................................... 24
7.
FUTUREWORK ................................................................................................................. 24
8.
REFERENCES .................................................................................................................... 25
LIST OF FIGURES Figure 1 - Ladder Type of Chassis.................................................................................................. 6 Figure 2 - Self-Support Chassis (Mobilinanews) ........................................................................... 7 Figure 3 - Triangulation in Structures............................................................................................. 8 Figure 4 - Tubular Space Frame Chassis of Hacettepe Racing Formula Student Team................. 8 Figure 5 - Monocoque Chassis of Darmstadt Technical University Formula Student Race Car ... 9 Figure 6 - Examples of Main Hoop Structural Requirements ...................................................... 17 Figure 7 - Front Hoop Iteration Examples .................................................................................... 18 Figure 8 - Longitudinal Sections of Chassis with 95th Percentile Male Model ........................... 18 Figure 9 - Chassis Floor Layout ................................................................................................... 18 Figure 10 - 3D Sketch of Chassis with 95th Percentile Male Model and Engine ........................ 19 Figure 11 - Isometric View of Completed Chassis ....................................................................... 19 Figure 12 - Front View of Chassis ................................................................................................ 20 Figure 13 - Side View of Chassis ................................................................................................. 20 Figure 14 - Top View of Chassis .................................................................................................. 20 Figure 15 - Chassis Triangulation Rule ........................................................................................ 21 Figure 16 - Hacettepe Racing Chassis Design for FS 2015, Class 2 ............................................ 22
LIST OF TABLES Table 1 - Comparison of Steel vs Aluminum ............................................................................... 13 Table 2 - Design Starting Criteria ................................................................................................. 17 Table 3 - Baseline Steel Tubing Requirements............................................................................. 21 Table 4 - Frame Members, Specifications and Rule Numbers ..................................................... 22 Table 5 - Sample SES Data of Main Hoop ................................................................................... 23
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1. INTRODUCTION Formula student is one of the biggest and most prestigious educational engineering competition in the world, especially in the field of mechanical and automotive engineering. This competition is supported by big automotive companies and also Formula One teams and it is considered as the top level engineering competition for students.
The aim of Formula Student series is to incite and encourage young candidate engineers and improve their abilities in the areas of engineering skills, team work capabilities, time and project management and presentations skills. On the other hand, Formula Student is a very suitable environment for automotive and racing industry to find their employees in future.
The first event was organized by Society of Automotive Engineers (SAE) in the United States in 1981. And in the upcoming years, some of US and UK teams competed in UK. So the second event of the Formula Student series started in UK in 1998. With the spread to other countries The Institution of Mechanical Engineers (IMechE) became the organizer of the European series of the competition.
Besides, the given importance to the Formula Student competitions increased each passing day. This drawed interests of big automotive companies and more importantly Formula One teams. Many leading names in the sector began to support and became Patron, judges or volunteers of Formula Student. All these developments provided to spread all over the world. Now Formula Student competitions are organized in Michigan (US), Lincoln (US), UK, Australia, Brazil, Italy, Austria, Germany, Japan and Russia.
Being a versatile competition in order to provide progressive learning opportunities increases Formula Student’s importance. The competition consists of several events aspiring better learning and self-improvement of students. There are two main entry categories in FS which are Class 2 and Class 1.
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In general, Class 2 is advised for first year teams. In this class, teams compete with only their designs. Teams are judged in three static events; Design, Business Presentation as well as Cost and Sustainability. Teams are also encouraged to produce some parts of vehicle.
Class 1 is for the teams which have fully constructed a running car. This class is more extensive and consists of static and dynamic events. Static events are same with Class 2. Additionally, there is a technical inspection and five tests which are safety, chassis, brake, noise and tilt tests. The teams which pass the technical inspection (scrutineering) and five tests are qualified for dynamic events. Dynamic events are Acceleration, Skid Pad, Autocross and Endurance & Fuel Economy.
2. LITERATURE REVIEW 2.1.
Definition and History
With the first appearance of automobiles in the end of the 18th century, it took almost a century, the development of combustion engine powered automobiles. Before long the first automobile race was organized in United States in 1895 (www.eyewitnesstohistory.com, 2006). Being a strong competitive environment, automobile races have taken the lead of faster development of cars. Thus automobile races are good opportunity for the manufacturers. Because they always have to be faster, stronger and safer.
Chassis is one of the most important part of vehicles. It has several functions. It is analogous to skeleton of animals. Chassis hold almost all of the components of vehicle together. At the same time, it serves a safe zone for drivers to protect them. Chassis must be strong enough to remain robust in every operational conditions for its expected life and also be as light as possible to be fast. It carries the suspension system and that’s why, chassis must minimize body deflection as bending and torsion in any direction. This chassis stiffness affects vehicle’s dynamic behaviors like road holding and handling.
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2.2.
Chassis Types
In automotive and racing industries, depending on application types, regulations and performance & safety parameters; various chassis types have been used. With the continuous advancement of technology in terms of analysis methods and production, chassis used in races has become more effective and complex. In this part, most used chassis types will be compared and the selection criteria will be referred to the appropriate chassis.
2.2.1. Ladder Chassis
Ladder chassis is the oldest type of chassis. It is quite primitive and has very simple design. This type of chassis has been used since 1950s and today, very few vehicles have ladder chassis. They mainly consist of two longitudinal frame member and this design looks like ladder. These two main members carry the most of the vehicle’s weight and it is a support against the longitudinal forces caused by acceleration and braking. But ladder chassis are so weak in terms of torsional rigidity. There are cross members which supports the vehicle to the lateral forces. (Milliken & Milliken, 1995)
Ladder chassis has the advantage of easy manufacturing and price. Their production and material costs are quite low. But not being three dimensional structure reduces torsional stiffness of the vehicle (Bappa, Jose, Muteen, & Shaikh, February, 2015).
Figure 1 - Ladder Type of Chassis
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2.2.2. Self-Support Chassis
Self-support chassis, also known as Unibody Chassis are the most used chassis types today. It is widely used especially in passenger cars. The design of this chassis type consists of one main strong structure by integrating frame and body together. The entire body is formed from shaped metal panels. It is easier to weld these panels compared to the conventional chassis and bodies. Selfsupport chassis also have the advantage of good load capability. Being fully integrated structure makes the chassis to have well load distribution. Another advantage of this design is space saving and weight reducing. Minimizing wasted material and production processes are valid reason for mass production (European Aluminum Association, 2013).
Figure 2 - Self-Support Chassis (Mobilinanews)
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2.2.3. Space Frame Chassis
Space Frame or Tubular Space Frame chassis are made from steel or aluminum tubes integrated together with triangulation. Main advantage of this design is its three dimensional structure. This structure increases the torsional rigidity of the vehicle significantly. In the triangulated form, there are only tension and compression. The frame members are not exposed to bending or twisting loads (Oshinibosi, August 30, 2012).
Figure 3 - Triangulation in Structures
By taking advantage of reducing weight, the performance capabilities of the vehicle are increased. On the other hand, being a very stiff structure in all directions minimize the body deflection under operating stress. This aspect this helps the suspension geometry to keep the road as much as possible (Adams, 1993).
Figure 4 - Tubular Space Frame Chassis of Hacettepe Racing Formula Student Team
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2.2.4. Monocoque Chassis
Monocoque chassis are consists of one primary structure that is the body and frame of the vehicle. It also gives the vehicle the outer shape of it. These type of chassis are made of composite materials. It has great rigidity to weight ratio. They are very lightweight structures. So, this makes the vehicle to have better performance. Monocoque chassis are produced from lots of composite layers and requires special production procedure. The disadvantage of this chassis type is high cost (Bappa, Jose, Muteen, & Shaikh, February, 2015).
Figure 5 - Monocoque Chassis of Darmstadt Technical University Formula Student Race Car
2.3.
Comparison of Chassis Types
By inspecting the chassis types and by making benchmark, tubular space frame chassis are preferred for formula student teams. Ladder chassis are very weak for torsion. Self-support chassis are suitable for mass production for companies and manufacturers. For hand made cars like formula student, two of these types are convenient; space frame and monocoque. Monocoque chassis have good rigidity and very light weight. But its complex structure and price are disadvantages. Space frame structures are slightly heavier than monocoque but they are still considered as light weight. For formula student races, acceleration is very important. Also road holding capabilities must be as high as possible. Considering all these arguments, space frame chassis is the most convenient chassis type for formula student teams. 9
3. MATERIALS FOR CHASSIS COMPONENTS 3.1.
Steel
Steel is the mostly used material in automotive industry. There are various parts made of steel. Its availability and being relatively low cost makes steel so convenient to produce chassis, some of body parts and kinds of other components (Geoff Davies F.I.M., 2003).
Besides low cost, steel has another advantages. It can be easily shaped, machined and welded. On the other hand, it is a good property that there is not so much brittle area because of heat effected zone after welding.
Need to be mention material properties of steel for Formula Student, there is some regulations in rules. Minimum yield strength of used material needs to be 305 MPa and minimum tensile strength is 365 MPa. The young modulus should be at least 200 GPa. Also the steel has to have minimum of 0.1 % carbon (SAE International, May 11, 2015).
There are mainly two types of steel used in Formula Student cars; SAE 4130 steel and mild steel. SAE 4130 has high carbon composition and mild steel has relatively low carbon. High carbon steels are very strong but they are expensive and there are some difficulties for production. Welding is harder and heat treatment after welding may be required. However, low carbon steels can be easily welded and heat treatment is not necessary. And also painting and repairing of low carbon steel are easier (Waterman, November 7, 2011).
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3.2.
Aluminum
Aluminum is the second most popular material in automotive. In recent years, aluminum utilization rate in automotive industry became grow rapidly. The biggest reason is its light weight. Aluminum is nearly three times lighter than steel. Besides, aluminum is malleable and elastic material. On the other hand, aluminum is corrosion resistant and does not rust (European Aluminum Association, 2013).
Although aluminum is not stiff as steel, it gives enough strength in some applications. But according to general material properties of aluminum, larger dimensions should be used in order to provide required stiffness. (Diaz, Fernandez, Gonzalez, & Ramos, 2014)
The main disadvantage of aluminum is its price. It is more expensive than steel. It may not be problem for race cars or expensive sports car but it is not suitable to use lots of part made by aluminum for mass production vehicles. Also welding o aluminum is harder.
3.3.
Composites
As a general definition, composite materials are made by using two or more substances. They give their properties and the specification of new product has a combination of these substances. Also, it is different than each of their own properties. Usage of composites is increasing day by day. Composite chassis are mostly used in high level applications like Formula 1, some race series and upper class sports car. They have very good strength properties and lighter than metals. Also composite materials can be produced for special applications. Their mechanical characteristics can be adjusted. Their internal structure gives a good strength in preferred direction (Aird, 1996).
The main disadvantage of composite chassis is that they are very expensive and they require staging production methods.
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3.4.
Material Selection Criteria
For Formula Student competition, the baseline material is steel and the regulations and rules are held regarding alloy steels. It is also possible to use another material, but in order to use them the alternative frame rules should be considered. There are much more rules, regulations and required tests for the use alternative materials.
The most common chassis materials are steel and composite in Formula Student. With an increase of usage of composites, more than half of teams use steel for their chassis.
Aluminum has the advantage of being lighter than steel and cheaper than composite, it is very hard to find aluminum that meets the requirements of rules. And to provide enough stiffness, larger size of aluminum must be used and this does not make aluminum to be very convenient choice. The volume of material becomes larger and it increases price.
Composite chassis are very good option for teams. Because they are light and stiff. But it must be considered that composite monocoque chassis are hard to produce and very expensive.
The most convenient choice is using steel to produce space frame chassis. It is easy to machine and prepare the tubes. It may not require also a complex fixture for production. With using correct material, any post process is not necessary. After all, steel is very cheap and has a good availability.
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Table 1 - Comparison of Steel vs Aluminum
Density (g/cm3)
Yield/Tensile Strength (Mpa)
Elastic Modulus (GPa)
Base Metal Price (%)
Steel, SAE 1040 (Cold Drawn)
7.8
530 / 630
210
2.9
Steel, SAE 4130 Tempered
7.8
979 / 1040
210
3.0
Stainless Steel, 304L
7.9
310 / 620
200
4.1
Aluminum, 6061-T6
2.7
270 / 310
69
16.0
Aluminum, 7049-T7352
2.84
420 / 520
72
16.0
Aluminum, 4015 - H16
2.71
170 / 200
71
16.0
Material
As shown in the Table-1, steel is nearly three times heavier than aluminum and in general steel has higher yield and tensile strength. Steel is stiffer than aluminum. It can be determined from its elastic modulus. And the base metal price of aluminum is nearly four times of steel. Base Metal Price: “A measure of the relative cost of different metals, based on the commodity market prices of their alloy constituents. Values are calculated on a unit mass basis, and expressed as a percentage of the highest value in the database. Values are not updated frequently, and therefore may not capture short-term fluctuations.” (http://www.makeitfrom.com/)
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4. PRODUCTION METHODS When designing chassis, it is desired that the chassis must be strong enough and stiff. So the production methods should be selected properly and convenient in order to attain the design goals. There are many methods for chassis production according to chassis types. Not only the strength, stiffness and body integration, but also post production processes and the capabilities of the vehicle in terms of easy disassembling and repairing must be considered.
4.1.
Mechanical Joint
Mechanical joint is a useful method for some applications. Especially, if the parts which is integrate to each other are wanted to be non-permanent. It is a good option when there is a possibility that a specific parts of chassis are needed to be replaced or disassembled. Also the mechanical joints can be used as a fuse. For example, if there is a critical part in the design which is wanted not to be damaged, it the mechanical joint can be designed for integrating these parts with main structure. And the joint is designed as weaker part; so it fails first when high loads are applied. This protects entire body or system from bigger damages. It is also cheaper and easier to replace this joint.
4.2.
Welding
The most common used method to join two or more metal pieces together is welding. In general, welding is made by melting the work pieces and adding a filler material. However, there are welding types that does not require any melting or filler addition. Also welding can be done hot or cold. On the other hand, welding can be applied with pressure or without pressure. All these methods depend on application type. (Pritchard, 2001)
As well as there are many types of welding, the most common used methods of non-pressurized welding types are explained in following section.
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4.2.1. Stick / Arc Welding
Stick welding, also known as shielded metal arc welding (SMAW) is one of the most used welding method. It takes its name from the shape of the electrode. In this welding process, the current comes from the welding machine is constant and can be direct current (DC) or alternating current (AC). The amount of drawn current is proportional to thickness of work pieces.
This welding is generally used to weld steel and iron. The arc heat is used in this method to melt the work pieces and stick. The stick used an electrode and with the work pieces, they complete an electric circuit.
4.2.2. MIG Welding
MIG (Metal Inert Gas) welding is the method that the welding is done with continuous filler stick in protected area with gas. Generally, Argon or Helium are used as an inert gas. There is another version of this type of welding, called as Metal Active Gas (MAG) welding that Carbon dioxide is used as active gas. In this method, the required amount of energy exists by the electric arc between the work pieces and filler stick. The welding torch feeds the filler material to the welding zone, at the same time the protective gas is applied in order to protect welding zone from environment conditions. (Jeffus, 2012)
MIG welding has relatively high melting speed and deeper penetration ability. It is the advantage of usage that it allows welder to work nonstop in a wide angle. On condition that required electrode and protective gas is supplied, MIG welding can be used for ferrous and nonferrous metals.
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4.2.3. TIG Welding
Tungsten inert gas (TIG) welding is also known as gas tungsten arc welding (GTAW). In older applications, the used protective gas was helium and this welding process called as heliarc. But with the improvements, it is discovered that polarity makes the process be more effective and has a reduced cost.
In this method, the tungsten electrode does not melt in normal conditions. The welding arc exists between the work pieces and electrode. The heat energy makes a weld pool and filler stick is fed externally to the pool. The tungsten is a sensitive material to oxygen, so a protective zone is required to protect the electrode. Generally, argon or helium is used as inert gas. But argon is widely used because of its better cleansing properties. (Jeffus, 2012)
4.3.
Hybrid Chassis
In Formula Student competition series, experienced teams tend to use hybrid chassis in order to optimize weight and stiffness properties of their vehicle. It can be possible to use body which made of fully constructed from composites (monocoque chassis), some teams prefer hybrid chassis. The frontal part of chassis is monocoque and the rear part which carries the powertrain is made of space frame structure. This two different type of structures are integrated to each other with mechanical joint. Especially the teams which use internal combustion engine select this option. Even if the chassis is fully constructed as monocoque, the main hoop must be one-piece continuous steel tube. In any case that teams should use mechanical joints to fix the main hoop to the body.
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5. DESIGN 5.1.
Design Overview
Regarding to the Formula SAE rules and literature research, some of parameters are determined to start designing chassis. These parameters are wheelbase, track width, cockpit dimensions, tire sizes, ride height and some general dimension constraints. The wheelbase must be minimum 1525 mm. Also the smaller track width can be minimum 75% of larger track width. (SAE International, May 11, 2015). Before starting to design, the parameters given in Table-2 given below are determined.
Table 2 - Design Starting Criteria
Wheelbase
1650 mm
Front Track Width
1260 mm
Rear Track Width
1220 mm
Tire Size
13”
Ride Height
60 mm
In addition to general dimensional requirements, there are also some structural rules. Formula Student constraints teams to design their chassis. Especially, the driver cell is very important. So main and roll hoops designs become very important. There are some structural standards. Teams which do not obey these rules cannot be approved to the Structural Equivalency Spreadsheet (SES). There are some examples of acceptable and non-acceptable main and front hoop designs in Figure-6.
Figure 6 - Examples of Main Hoop Structural Requirements
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5.2.
CAD Design
CAD design is started in Solidworks according to general dimensional requirements and design criteria. At first, main and front roll hoops are designed individually and optimum shapes are determined by iterating.
Figure 7 - Front Hoop Iteration Examples
After that, the floor layout of chassis is sketched according to cockpit requirements and components that predetermined before. 95th percentile male model is used to provide wide cockpit area and longitudinal sections of chassis are also separated.
Figure 9 - Chassis Floor Layout
Figure 8 - Longitudinal Sections of Chassis with 95th Percentile Male Model
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After the reference lines and layouts are determined and designed, upper structures, side impact structures and roll hoops are completed and 3D sketch of chassis comes in sight.
Figure 10 - 3D Sketch of Chassis with 95th Percentile Male Model and Engine
By doing so many iterations, the final design of the chassis is completed. Analyses, component placements, Formula Student technical tests like tilt test, vehicle dynamic requirements, center of gravity specifications and many other criteria have a role in these iterations.
Instead of using one type of steel tube, different sizes and materials are used to produce chassis structure. On order to find best weight and strength optimization, main and front roll hoops are designed one piece bended 30.0x3.0 ST52-3 steel. Other frame members are made of 25.4x1.80 S460 MC micro alloy steel.
Figure 11 - Isometric View of Completed Chassis
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Figure 12 - Front View of Chassis
Figure 13 - Side View of Chassis
Figure 14 - Top View of Chassis
5.3.
Analysis Methods
There are standard regulations for chassis design in Formula Student. The rules are based on steel tubing. If teams use different materials, they have to provide required structural equivalency. These rules and requirements are listed in Formula SAE rules book. But, if the chassis is made of space frame steel, there are only some constraints about hoops, bracings, tube dimensions and structural requirements like triangulation. Some of these rules are listed below.
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Figure 15 - Chassis Triangulation Rule
The baseline steel material is AISI 1010 Steel. The Primary Structure of the car must be constructed of either round, mild or alloy, steel tubing (minimum 0.1% carbon) of the minimum dimensions specified in the following Table-3.
Table 3 - Baseline Steel Tubing Requirements
ITEM or APPLICATION
OUTSIDE DIMENSION x WALL THICKNESS Round 1.0 inch (25.4 mm) x 0.095 inch
Main & Front Hoops,
(2.4 mm) or Round 25.0 mm x 2.50 mm
Shoulder Harness Mounting Bar
metric Round 1.0 inch (25.4 mm) x 0.065 inch
Side Impact Structure, Front Bulkhead, Roll Hoop Bracing, Driver’s Restraint Harness Attachment (except as noted above) EV: Accumulator Protection Structure
Front Bulkhead Support, Main Hoop Bracing Supports EV: Tractive System Components
(1.65 mm) or Round 25.0 mm x 1.75 mm metric or Round 25.4 mm x 1.60 mm metric or Square 1.00 inch x 1.00 inch x 0.047 inch or Square 25.0 mm x 25.0 mm x 1.20 mm metric
Round 1.0 inch (25.4 mm) x 0.047 inch (1.20 mm) or Round 25.0 mm x 1.5 mm metric or Round 26.0 mm x 1.2 mm metric
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The chassis members and their specifications with corresponding Formula SAE rules are listed in Table-4 given below.
Table 4 - Frame Members, Specifications and Rule Numbers Rule No. T3.11 T3.12 T3.13 T3.13 T3.14 T3.18 T3.19 T3.24 T5.4
Rule Description Main Roll Hoop Tubing Front Roll Hoop Tubing Main Roll Hoop Bracing Tubing Main Hoop Bracing Support Tube Frames Front Hoop Bracing - Tube Frames Front Bulkhead - Tube Frames Front Bulkhead Support - Tube Frames Side Impact Structure - Tube Frames Shoulder Harness Bar
Design Description and/or Material Used Steel Steel Steel
Tube Material
Tube Type
Outside Dimension
Wall Thickness
Steel Steel Steel
Round Round Round
30.0 30.0 25.4
3.00 3.00 1.80
Steel
Steel
Round
25.4
1.80
Steel
Steel
Round
25.4
1.80
Steel
Steel
Round
25.4
1.80
Steel
Steel
Round
25.4
1.80
Steel
Steel
Round
25.4
1.80
Steel
Steel
Round
30.0
3.00
Figure 16 - Hacettepe Racing Chassis Design for FS 2015, Class 2
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Specifications of every frame members and materials used in chassis are sent in the Structural Equivalency Spreadsheet. There are also baseline steel requirements. One of the example data are given below in Table-5. Table 5 - Sample SES Data of Main Hoop
Material Property Material type Tube shape Material name /grade Young’s Modulus, E Yield strength, Pa UTS, Pa Yield strength, welded, Pa UTS welded, Pa
Baseline Steel Round Steel 2E+11 305000000 365000000 180000000 300000000
Used Steel Round Steel 2E+11 305000000 365000000 180000000 300000000
Tube OD, mm Wall, mm
25.4 2.4
30 3
Baseline 0.0254 0.0024 1.15935E-08 2318.69797 173.4159145 52891.85392 63296.80878 31214.86461 52024.77434
Used 0.03 0.003 2.34778E-08 4695.5619 254.4690049 77613.04651 92881.1868 45804.42089 76340.70148
OD, m Wall, m I, m^4 EI Area, mm^2 Yield tensile strength, N UTS, N Yield tensile strength, N as welded UTS, N as welded Max load at mid span to give UTS for 1m long tube, N Max deflection at baseline load for 1m long tube, m Energy absorbed up to UTS, J
1332.794896 2285.173458 0.011975066 0.005913363 7.980153166 11.58455989
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6. CONCLUSION In this report, the basics of chassis design is represented. Most commonly used production methods and materials are considered. Regarding previous year’s design, judge feedbacks and literature survey; the most convenient way is selected. By this selection, the steel space frame chassis is designed. This design is the most suitable chassis for first year competitors. The easiest procedure is applied in terms of fixturing, easy manufacturing and production.
7. FUTUREWORK The chassis is designed for first year Class-1 competition, so that it needs many improvements. This first chassis can be considered as a prototype and it must be redesign with advanced methods. After first year competition and first assembly, the deficiencies must be eliminated, because first productions are generally not perfect.
The first step can be validation of structural integrity and strength of chassis. It should be tested and results must be compared with analysis. Regarding this comparison, the required optimization must be applied for next year chassis. On the other hand, vibration tests and modal analysis can be applied. According to first road tests, the ergonomic improvements must be applied. Driver’s comfort, handling angle of view, ease of control of the vehicle are some of the important parameters for chassis design. Another case is that, the suspension behaviors should be tested and compared with the design goals. After having real test data, rigidity of chassis and its distribution can be adjusted more effectively. Finally, as a long term aim, the other chassis types must be considered for best weight and strength properties and performance parameters. The team should study on composite monocoque chassis in a couple of years.
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8. REFERENCES
1. Adams, H. (1993). Chassis Engineering. 2. Aird, F. (1996). Fiberglass & Composite Materials. 3. Bappa, M., Jose, J., Muteen, A., & Shaikh, M. (February, 2015). Design & Finite Element Analysis of a Formula Student Chassis. 4. Costin, M., & Phipps, D. (1961,1965). Racing and Sports Car Chassis Design. 5. Diaz, A., Fernandez, O., Gonzalez, R., & Ramos, C. (2014). FSAE 2015 Chassis and Suspension . Florida: Florida International University Mechanical Engineering . 6. European Aluminum Association. (2013). The Aluminum Automotive Manual. 7. Geoff Davies F.I.M., M. (. (2003). Materials for Automobile Bodies. 8. http://www.makeitfrom.com/. (n.d.). 9. Jeffus, L. (2012). Welding Principles and Applications. Delmar, Cengage Learning. 10. Milliken, W., & Milliken, D. (1995). Race Car Vehicle Dynamics. Warrenda: SAE. 11. Mobilinanews. (n.d.). Retrieved from http://mobilinanews.com/post/mengenal-kelebihansasis-mobil-monokok/ 12. Oshinibosi, A. (August 30, 2012). Chassis and Impact Attenuator Design For Formula Student Race Car. 13. Pritchard, D. (2001). Soldering, Brazing & Welding. Ramsbury, United Kingdom: The Crowood Press Ltd. 14. SAE International. (May 11, 2015). 2016 Formula SAE® Rules. 15. Waterman, B. J. (November 7, 2011). Design and Construction of a Space-frame. 16. www.eyewitnesstohistory.com. (2006). "America's First Automobile Race, 1895", EyeWitness to History, .
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