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Page 1
Design and Manufacturing of Chassis and Body of an FSAE Car
Submitted in Partial Fulfillment of the Requirement for Award of the Degree of Bachelor of
Automobile Engineering
By
Dhaval Patel BE 826
Yogesh Dhakan BE 808
Hanisha Singh Rao BE 832
Sukhdeep Singh Panesar BE 825
Supervisor:
Prof. Vinayak Khatawate
Department of Automobile Engineering
Pillai's Institute of Information Technology, Engineering, Media Studies and Research, New Panvel, Navi Mumbai-410 206.
University Of Mumbai
2015-2016
Page 2
CERTIFICATE This is to certify that the project entitled "Design and Manufacturing of Chassis
and Body of FSAE Car" is a bonafide work of
Yogesh Dhakan (BE 808)
Dhaval Patel (BE 826)
Hanisha Singh Rao (BE 832)
Sukhdeep Singh Panesar (BE 825)
submitted to the University of Mumbai in partial fulfilment of the requirement for the award of the degree of
Bachelor of Engineering
in Automobile Department.
___________________ ____________________
Prof. Vinayak Khatawate Prof. Miriyala Durga N. K.P. Rao
(Guide) ( Project Cordinator)
_______________________ ___________________________
Prof. Dr. Dhanraj P. Tambuskar Prof. Dr. R. I. K. Moorthy
(Head of Automobile Department) (Principal)
Page 3
Approval Sheet
This project report entitled
"Design and Manufacturing of Chassis and Body of FSAE Car"
By
Dhaval Patel
Yogesh Dhakan
Hanisha Singh Rao
Sukhdeep Singh Panesar
is approved for the Degree of Automobile Engineering in the Department of Automobile Engineering,
Pillai Institute of Information Technology, Engineering, Research & Media Studies, New Panvel-410 206 affiliated to University of Mumbai.
Examiners:
1._________________________
2._________________________
Supervisors:
1._________________________
2._________________________
Chairman
__________________________
Date:
Place:
Page 4
Declaration
We declare that this written submission represents my ideas in my own words and where others' ideas or words have been included, we have adequately cited and referenced the original sources. We also declare that we have adhered to all principles of academic honesty and integrity and have not misrepresented or fabricated or falsified any idea/data/fact/source in my submission. We understand that any violation of the above will be cause for disciplinary action by the Institute and can also evoke penal action from the sources which have thus not been properly cited or from whom proper permission has not been taken when needed.
Name of Members Roll no. Signature
Yogesh Dhakan 808 _____________________
Dhaval Patel 826 _____________________
Hanisha Singh Rao 832 _____________________
Sukhdeep Singh Panesar 825 _____________________
Date:
Page 5
Abstract
The Formula SAE Series competitions challenge teams of university undergraduate and
graduate students to conceive, design, fabricate, develop and compete with small, formula style,
vehicles.
The vehicle must accommodate drivers whose stature ranges from 5th percentile female
to 95th percentile male and must satisfy the requirements of the Formula SAE Rules. Additional
design factors to be considered include: aesthetics, cost, ergonomics, maintainability,
manufacturability, and reliability.
The team has developed the 2015 chassis and body panel for the Hyperion racing Formula SAE
vehicle – HRT02. Several factors were taken into account, including vehicle dynamics, chassis
rigidity, vehicle component packaging and overall vehicle manufacturing and performance. This
project is split into five phases
(i) Design
(ii) Analysis
(iii) Manufacturing
(iv) Test (Chassis)
(v) Validation (Chassis)
Page 6
List of Figures
Figure 2.1- Ladder chassis of a Ford street rod car..............................................................4
Figure 2.2 - Twin Tube Chassis of Lister Jaguar Race Car..................................................5
Figure 2.3- Four Tube Chassis................................................................................................5
Figure 2.4- Backbone Chassis of Lotus Elan Sports Car......................................................6
Figure 2.5 - Tubular space frame chassis of Galmer D-Sport race car...............................7
Figure 2.6 - Stressed skin/monocoque chassis of Strakka race car......................................8
Figure 3.1 - Design Methodology for chassis........................................................................10
Figure 3.2 - Design Methodology for body..........................................................................11
Figure 3.3- Helmet Clearance...............................................................................................19
Figure 3.4- Side Impact member...........................................................................................20
Figure 3.5- Cockpit Opening..................................................................................................21
Figure 3.6 : Cockpit Template...............................................................................................22
Figure 3.7: HRT 02 Car.........................................................................................................26
Figure 3.8: Frame design with the major components preliminary design for the vehicle
chassis.......................................................................................................................................26
Figure 3.9 : Side view of a preliminary design for the vehicle chassis...............................27
Figure 3.10 : Top view of the same design............................................................................27
Figure 3.11: Final chassis design side view...........................................................................30
Figure 3.12: Final chassis design top view............................................................................31
Figure 3.13 : Impact Attenuator............................................................................................32
Figure 3.14: Chassis view from front....................................................................................32
Figure 3.15 : Isometric view of chassis..................................................................................33
Figure 3.16: Mass properties of chassis................................................................................34
Figure 4.1 : Frontal Impact Analysis of Chassis..................................................................36
Figure 4.2 : Static Deflection of Chassis................................................................................36
Figure 4.3 : Torsional Deflection of Chassis ........................................................................37
Figure 4.4 : Torsional load on chassis...................................................................................38
Page 7
Figure 5.1 : 95th percentile male template...........................................................................39
Figure 5.2 : Ergonomics rig....................................................................................................40
Figure 5.3 : 3-D driver............................................................................................................41
Figure 5.4 : Integration of ergonomic test plates and chassis design.................................41
Figure 5.5: Side-view of ergonomic test plates and chassis.................................................42
Figure 5.6: Tube Profiling of chassis members....................................................................43
Figure 5.7 : Fixtures for Chassis Structure..........................................................................43
Figure 5.8 : Weldments at Joints...........................................................................................44
Figure 5.9 : Final Structure of Chassis.................................................................................44
Figure 5.10: Prototype 1 and 2 up and down.......................................................................45
Figure 5.11: Isometric view of both body prototypes..........................................................45
Figure 5.12: Laying Process of FRP......................................................................................46
Figure 5.13 : Machining of Poly Urethane Foam For mould..............................................47
Figure 5.14 : Foam ready for laying......................................................................................47
Figure 5.15 : Laying Process of Fiberglass..........................................................................48
Figure 5.16 : Final Painting of Body....................................................................................48
List of Tables
Table 3.1 Materials for chassis..............................................................................................12
Table 3.2 Decision matrix for chassis...................................................................................13
Table 3.3 Materials for body.................................................................................................14
Table 3.4 Decision matrix for body.......................................................................................15
Table 3.5 Minimum material requirements.........................................................................25
Table 3.6 Result table of iterated chassis.............................................................................51
Page 8
Index
Certificate...................................................................................................................................i
Approval Sheet.........................................................................................................................ii
Declaration...............................................................................................................................iii
Abstract....................................................................................................................................iv
List of Figures...........................................................................................................................v
List of Tables...........................................................................................................................vi
Chapter 1: Introduction...........................................................................................................1
1.1 Need.........................................................................................................................1
1.2 FSAE Background..................................................................................................1
1.3 Objective.................................................................................................................2
Chapter 2: Literature Survey................................................................................................3
2.1 Types of Chassis ....................................................................................................3
2.1.1 Ladder Chassis .......................................................................................3
2.1.2 Twin Tube Chassis..................................................................................4
2.1.3 Four Tube Chassis...................................................................................5
2.1.4 Backbone Chassis ...................................................................................6
2.1.5 Tubular Space frame Chassis................................................................6
2.1.6 Stressed Skin /Monocoque Chassis........................................................7
2.2 Addressing Global Design......................................................................................9
Chapter 3: Problem Definition and Design Methodology..................................................10
3.1 Problem Definition...............................................................................................10
3.2 Design Methodology............................................................................................10
3.2.1 Chassis Selection....................................................................................11
3.2.2 Material Selection..................................................................................11
3.2.2.1 Material selection for chassis..............................................11
3.2.2.2 Material selection for body..................................................13
3.3 Constraints and Other Considerations...............................................................15
Page 9
3.3.1 Rule Requirement.................................................................................15
3.3.1.1 Definitions of Rules considered in FSAE
chassis designing.....................................................................15
3.3.2 Chassis Rules.........................................................................................16
3.3.2.1 Main and Front Roll Hoops..................................................16
3.3.2.2 Main Hoop..............................................................................17
3.3.2.3 Front Hoop .............................................................................17
3.3.2.4 Main Hoop Bracing ...............................................................18
3.3.2.5 Front Hoop Bracing...............................................................18
3.3.2.6 Other Bracing Requirements................................................19
3.3.2.7 Other Side Tube Requirements............................................19
3.3.2.8 Frontal Impact Structure......................................................19
3.3.2.9 Bulkhead................................................................................19
3.3.2.10 Front Bulkhead Support......................................................20
3.3.2.11 Side Impact Structure .........................................................20
3.3.2.12 Cockpit Opening...................................................................21
3.3.2.13 Cockpit Internal Cross Section...........................................22
3.3.2.14 Jacking Point.......................................................................22
3.3.2.15 Minimum material requirement.........................................23
3.3.3 Function of Chassis..............................................................................23
3.3.4 Attributes of Chassis.............................................................................23
3.3.4.1 Weight.....................................................................................24
3.3.4.2 Structural Strength................................................................24
3.3.4.3 Structural Stiffness.................................................................24
3.3.4.4 Specific Structural Strength & Stiffness..............................24
3.3.4.5 Crashworthiness.....................................................................24
3.3.4.6 Durability and Reliability.....................................................24
3.3.4.7 Manufacturability and Ease of Manufacture......................25
3.3.4.8 Ease of Access, Assembly and Maintenance........................25
Page 10
3.3.4.9 Performance Requirement....................................................25
3.3.5 Fundamental Requirement.................................................................26
3.3.6 Auxiliary Requirement.......................................................................26
3.4 Mathematical Analysis .......................................................................................29
3.5 Prototype 1...........................................................................................................30
3.5.1 Chassis....................................................................................................30
3.6 Design requirement..............................................................................................34
3.6.1 Fiberglass...............................................................................................34
Chapter 4: Finite Element Analysis of Chassis...................................................................35
4.1 FEA Analysis........................................................................................................35
4.2 Proposed Design....................................................................................................38
Chapter 5: Manufacturing and Verification.......................................................................39
5.1 Chassis.................................................................................................................39
5.1.1Ergonomic Integration...........................................................................39
5.2 Frame Improvements...........................................................................................45
5.3 Manufacturing of Body Panels...........................................................................46
5.3.1 Mould.....................................................................................................46
5.3.2 Fabrication of the body panel..............................................................46
5.3.3 Laying Process.......................................................................................46
Chapter 6: Conclusion and Future Recommendations......................................................49
6.1Conclusions............................................................................................................49
6.2 Future Recommendations....................................................................................49
6.3 Results..................................................................................................................50
Chapter 7: References............................................................................................................51
Acknowledgement..................................................................................................................53
Page 11
CHAPTER 1
INTRODUCTION
Formula SAE (FSAE) is a collegiate design competition sanctioned by the Society of
Automotive Engineers (SAE) for student members. The competition is based on the premise
that students have been hired by a manufacturing firm to produce a prototype Formula 1 style
racecar for consideration as a production item. The teams are encouraged to be creative in their
designs and push the boundaries of automotive engineering. The cars are designed and built
solely by the students and are then brought to one of the several regional competitions where
they compete against colleges from all over the world. Here not only are the cars tested on their
design and manufacturing, but the students are also tested on their ability to market their
prototype to a board of investors in a business fashion.
In the beginning phase of the project, the chassis with specific emphasis on FSAE
application is researched to gain more understanding. Multiple topics that are relevant to this
intention are reviewed. Sources and highlights of these literatures are acknowledged and
presented in this thesis.
1.1 Need: To construct a chassis required to comply with FSAE 2015 Rules for the Formula
SAE International Design Competition and build a body that is rigid and which weighs less.
1.2 FSAE Background: Hyperion Racing team is a team that makes race cars for Formula
student competitions. To date, the race team has constructed three chassis in all for their race car
and has accumulated a brief amount of knowledge and experience in the field of race car
engineering. Nonetheless, there is still a large area unexplored in the development of the chassis.
Page 12
Every year, only approximately five months are allocated for the development of the race car.
Within such intense period, the development of the chassis is limited. The understanding of the
race team on the subject of chassis for FSAE application is not too comprehensive due to the
tight schedule. The design of the chassis was somewhat impromptu and its final design was
often not highly optimized. Such situation has caused the race team to carry out the
development of the chassis in a somewhat rushing manner and the chassis was developed
mainly relying upon the experience and intuition of the team member in-charged. At present, the
evolution of the chassis is not on par with the development of the race car. With the goal of the
race team as becoming the top team in FSAE competition, this is a major issue for the race
team. This project is thus initiated with the ultimate aim of addressing this issue.
1.3 Objective: The objective is to carry out the development of the chassis and body for HRT
FSAE race car in a systematic comportment. In this project, the subject of chassis and body is
researched to gain understanding, with specific emphasis on FSAE application. Relevant
Computer-Aided Engineering (CAE) tools are researched and utilized to aid the development of
the chassis and body. There are three main tasks in this project, which are,
i. Design and Analysis of Chassis
ii. Design verification and manufacturing of Chassis
iii. Design and manufacturing of Body Panel
Page 13
CHAPTER 2
LITERATURE SURVEY
An FSAE chassis and body design is done yearly by every team that intends to
compete. There are various design types that have been explored that offer their own benefits
and costs. All of these designs follow the mandated specification given by the competition
rules, yet each of them is full of unique characteristics. In general, the vehicle’s wheelbase,
which is the distance between the axis of the front and rear wheel, has to be 60 in minimum .
Also, teams have a track width, which is the distance between the center of the left and right
tires, which is typically larger in the front than in the rear. By doing this, the rear of the car
can take a tighter path without hitting the cones that mark the edge of the track and the
vehicle can then navigate the corners tighter. The ratio between the vehicle’s wheelbase and
front track width ranges from 1.3 to 1.7 and affects the polar moment of the vehicle across its
longitudinal and lateral axis. This has a tremendous effect on how load is transferred between
the four wheels and by extension, the handling characteristics of the vehicle .
In terms of the chassis itself, there are a multitude of construction types allowed in the
competition rules, each providing their own advantages and disadvantages.
2.1 Types of Chassis :
2.1.1 Ladder Chassis :
a. Race cars of early days had the same kind of chassis as their passenger car
contemporaries. During that period, the configuration of the passenger car was
almost similar to that of the horse drawn carriage. Thus, race cars and passenger cars
Page 14
in early days inherited the same chassis construction as that of the horse drawn
carriage and it is the ladder chassis.
b. Ladder chassis was used primarily as the structure for body-on-chassis construction,
in which a separately manufactured body was mounted onto the chassis.
c. The main consideration for this chassis was its structural bending stiffness and little
attention was paid to structural torsional stiffness.
d. Ladder chassis was popular mainly due to its ease of manufacture and good bending
stiffness. In the development of the race car in early days, the powertrain was
focused on heavily; the development of the chassis was merely focused on building a
sufficiently strong supporting platform.
e. Today, ladder chassis is still widely used for heavy duty vehicles because of its
extreme simplicity.
f. A typical ladder chassis is shown in Figure3.1
Figure 2.1- Ladder chassis of a Ford street rod car
2.1.2 Twin Tube Chassis :
With the advent of independent suspension in mid-1930, the use of the ladder chassis for cars
became obsolete, especially in the field of racing.
The then newly introduced independent suspension did not operate effectively because
of the lack of structural torsional stiffness in the ladder chassis. A stiffer platform was
needed in order to improve the performance of race cars.
The use of twin tube chassis was a logical transition from the ladder chassis as engineers
were attempting to build chassis with better stiffness. The efficiency of the twin tube
chassis is however usually low due to the weight increase in using beams with larger
cross section. A typical twin tube chassis is shown in figure 3.2.
Page 15
Figure 2.2 - Twin Tube Chassis of Lister Jaguar Race Car
2.1.3 Four Tube Chassis :
a. As engineers sought to improve the chassis’ structural torsional stiffness, the twin
tube chassis evolved into the four tube chassis.
b. Using the configuration of the twin tube chassis as the base, two additional parallel
longitudinal beams were added and were laid on each side of the chassis on top of
the existing set of longitudinal beams.
c. With this chassis construction, significant increase in structural bending stiffness was
resulted.
d. However, there was little improvement in the structural torsional stiffness because of
the lozenging of the side of the chassis.
e. A typical four tube chassis is shown in figure 2.3
Figure 2.3- Four Tube Chassis
Page 16
2.1.4 Backbone Chassis :
Backbone chassis has a long history in the development of automobile and its origin is
credited to Hans Ledwinka, an engineer from Czech automaker, Tatra. Ferdinand
Porsche worked with him in the 1920’s and arguably learned much of his craft.
In this chassis construction, structural stiffness is derived from a large central beam
running the full length of the car.
This large central beam does not only provide the required structural strength and
stiffness, but also provide a tunnel space in the central section of the chassis for housing
the drive shaft that delivers power from the engine to the rear axle.
This type of chassis construction is well suited for automobile with side-by-side seating,
with a large central spine forming a centre console.
Late Collin Chapman used this type of chassis construction successfully on one of its
sport cars, Lotus Elan.
A typical backbone chassis is shown in figure 2.4
Figure 2.4- Backbone Chassis of Lotus Elan Sports Car
2.1.5 Tubular Space frame Chassis :
With the racing community began to realize the importance of the chassis’ structural
torsional stiffness, engineers turned to the tubular space frame construction in 1950s and
1960s.
Tubular space frame construction was firstly initiated in the aerospace industry back in
the era of world war two. As there were little breakthrough in the development of the
chassis for racing application, engineers began to look for inspiration beyond the
Page 17
automobile industry and came to realize the possible application of the tubular space
frame construction to the chassis construction.
In this chassis construction, multiple extrusions are spatially arranged in a truss-liked
manner. These extrusions are usually small in cross section and are orientated such that
each chassis’ member is only loaded in either tension or compression.
During that time, race engineers were astonished with this chassis construction because
of its effectiveness in improving the chassis’ structural torsional stiffness. With the
advent of the tubular space frame chassis, the development of the race car took a huge
leap.
As time progressed, race cars became lighter, faster and more predictable because of the
excellent characteristics of tubular space frame chassis.
Still, there are drawbacks with this type of chassis construction.
The manufacturing of tubular space frame chassis is usually labour-intensive and time-
consuming. Elaborate fixtures and jigs are required in order to precisely weld the
chassis.
Nevertheless, the tubular space frame chassis was a major improvement in the
development of the chassis despite these issues.
A typical tubular space frame chassis is shown in figure 2.5
Figure 2.5 - Tubular space frame chassis of Galmer D-Sport race car
2.1.6 Stressed Skin /Monocoque Chassis:
New technology in the aerospace industry had again led to the next evolution in the
development of the chassis. The combination of the development of stressed skin
structures during the depression and the emergence of fibrous materials in late 1960s
give birth the legendary composite stressed skin/monocoque chassis.
Page 18
This chassis construction had revolutionized several top levels racing series such as
Formula One and Indy Car Racing.
With this type of chassis construction, engineers had the ability to construct the chassis
that was with multiple functions, in which the chassis served as the structure, the body
and the aerodynamics control surfaces.
The use of advance composite material had resulted in an extremely light weight yet
stiff chassis.
The efficiency of the chassis as a structure and performance platform increased
tremendously. However, experience and knowledge gained in the aerospace industry
were not entirely applicable for the automobile, especially for the race car.
One main difference came from operation loads of these two different vehicles.
Loads on aircrafts are usually widely distributed, whereas loads on race cars are usually
concentrated. In order to effectively utilize the stressed skin chassis construction, load
spreading substructures are required and this reduces its efficiency.
In addition, the design and analysis of the stressed skin chassis is more complicated and
a great deal of resources is always required.
The continuous surface in the stressed skin chassis also considerably complicates the
maintenance of the race car. These drawbacks are the reason why this type of chassis
construction is rarely seen in racing series other than those high levels.
A typical stressed skin chassis is shown in figure 2.6
Figure 2.6 - Stressed skin/monocoque chassis of Strakka race car
Page 19
Amongst the types mentioned above, we have selected the tubular space frame chassis as its
dominant chassis construction. With the FSAE rules providing well-formed definitions and
guidelines for the space frame chassis, and also this being our debut competition, simplicity and
practicality was our approach which lead us to choosing the Space frame chassis. With
infrastructures and resources that the race team has access to at the present, this is the only
logical and next best form of chassis construction for the race team. Nevertheless, it offers
benefits like low cost and ease of modification, while also can be developed to provide high
specific structural strength and stiffness, despite the drawbacks mentioned previously.
2.2 Addressing Global Design
The automotive industry tends to build upon new innovative ideas stemming from the
continuously evolving motorsports industry. Prototype vehicles provide insight into possible
features or concepts that could eventually be integrated into production line cars. It is through
competition constraints that engineering teams push for new designs and solutions. Formula
SAE allows for the expansion of concepts of the modern car and pushes for the future of the
car of tomorrow through the collaboration of multi-disciplinary groups of engineers
attempting to build the best universally operable, open wheel weekend race car.
Like most ongoing research, the SAE community continuously builds upon previous failure and
success. Teams, like those belonging to Florida International University and University of Texas
at Arlington, create cycles of members that come and go for the opportunity to develop while
attending school. These projects strengthen social and engineering skills sought in the industries
nowadays.
Page 20
CHAPTER 3
PROBLEM DEFINITION AND DESIGN
METHODOLOGY
From the literature review we conclude that, the chassis should have an ideal torsional
stiffness of 1000 Nm/deg or greater while all the FSAE rules are followed. To achieve this we
have the problem defined as follows:
3.1 Problem Definition
To construct a chassis of high torsional rigidity and least possible weight and perform
stress and displacement analysis on the same.
To construct a body which is rigid and with least possible weight.
3.2 Design Methodology:
Figure 3.1- Design Methodology for chassis
Type of ChassisSelection based on
rules
Selection of Material
based on requirement and
availability
Designusing Solidworks
2013®
Finite Element Analysis
using Solidworks 2013®
Manufacturingtig welding and cnc
bending
Verificationusing CMM rover arm
Page 21
Figure 3.2 - Design Methodology for body
3.2.1 Chassis Selection
The structural torsional stiffness of the chassis is important because of its significant
contribution towards the handling characteristics of the race car. In order to produce a high
performing race car, it is extremely important that the race car to be tuned for optimal handling
characteristics. Several types of chassis constructions have emerged as engineers attempt to
tackle the challenge of engineering the chassis for race cars. These chassis constructions are
reviewed to gain more insight on the development of the chassis for racing application.
3.2.2 Material Selection
When selecting materials for motorsport applications the most common factors
considered are strength, cost and weight. In order to design a competitive vehicle it must be
light and yet strong.
3.2.2.1 Material selection for chassis
Some of the common material selected for chassis include but are not limited to AISI
1018, AISI 1020, AISI 4130, AISI 4340. The four materials mentioned were the main
considerations for the project.
Designing of Body Panel
using solidworks
Selection of Material
based on requirement and availability
Manufacturing including mould making
and process selectedPainting and Vinyl
Page 22
Table 3.1: Materials For Chassis
AISI 1018 AISI 1020 AISI 4130 AISI 4340
Density (kg/m^3) 7.8 7.7 7.85 7.85
Young's Modulus
(GPa) 210 210 205 200
UTS (MPa) 430 394.72 670 1255
YTS (MPa) 240 294.74 435 1165
Carbon, C 0.14 - 0.20 % 0.17 - 0.230 % 0.280 – 0.330% 0.370 - 0.430
Iron, Fe
98.81 - 99.26
% 99.08 - 99.53 % 97.03 – 98.22% 95.195 - 96.33
Manganese, Mn 0.60 - 0.90 % 0.30 - 0.60 % 0.40 – 0.60% 0.600 - 0.800
Phosphorous, P ≤ 0.040 % ≤ 0.040 % <0.035% <0.035
Sulphur, S ≤ 0.050 % ≤ 0.050 % <0.04% <0.04
Chromium, Cr 0% 0% 0.80 – 1.10% 0.700 - 0.900%
Molybdenum, Mo 0% 0% 0.15 – 0.25% 0.200 - 0.300%
Silicon, Si 0% 0% 0.15 – 0.30% 0.150 - 0.300%
Cost (INR) 51 57 83 184
Availability Easily Easily Difficult Difficult
Page 23
Table 3.2 : Decision Matrix of Chassis
3.2.2.2 Material selection for body
Similarly the common material selected for body panel include Carbon Fibre, Kevlar,
ABS Plastics, PP Plastics and FRP.
Material selection
The material for the body panel must be such that it fulfils all the pre-determined objectives and serves its purpose. Some of these objectives are:
1. It should be of low density in order to reduce the weight of our vehicle. 2. It must have adequate strength to bear the aerodynamic forces as well as its own
weight. 3. It should be manufactured with ease. 4. The material must be readily available at a minimal expense.
AISI 1018 AISI 1020 AISI 4130 AISI 4340 Requirements
Density 4 10 0 0 Low
Youngs’
Modulus
10 10 5 0 High
UTS 1 0 8 10 High
YTS 4 6 8 10 High
Cost 10 8 8 4 Least
Availability 10 8 4 4 Easily
TOTAL 48* 46 42 40
Page 24
Table 3.3: Materials for Body
Carbon Fibre Kevlar Glassfibre ABS Polypropylene
(PP)
Density(Kg/m^3) 1500-2000 1390 2250 1060-1080 905
Tensile strength (MPa) 2000-5600 2750-3000 3450-5000 42.5-44.8 33.094
Tensile Modulus (GPa) 180-500 80-130 69-84 - 1.344
Diameter (microns) 6-8 7-14 10-12 - -
Melting Point (degree
celcius)
3650 900-1000 840 105 164
Heat
Capacity(KJ/Kg.K)
0.92 1.05 0.71 - -
Thermal
Conductivity(W/mK)
10.03 2.94 13 - -
Coefficient of thermal
expansion(m/mK)
-1.0*10^6 -4*10^6 5*10^6 - -
Specific
strength(KN.m/Kg)
2457 2514 1307 - -
Melt flow (g/10 min) - - - 18-23 -
Hardness - - - 103-112 95
Elongation(%) - - - 23-25 12
Flexure Modulus(GPa) - - - 2.25 -
Max. temp (degree
celcius)
- - - 80 82
Availability Difficult Easily Easily
Cost Rs. 1000-
1200 psm
Rs. 400-550
psm
Rs.185 per
kg
Page 25
Table 3.4: Decision Matrix for Body
Carbon
Fibre
Kevlar Fiberglass ABS PP Requirem
ent
Density 5 7 4 9 10 Low
Tensile strength 10 7 9 3 2 Not imp.
Availability 2 9 9 10 7 easily
Cost 1 4 8 10 10 Least
Manufacturability (if industry
available)
Manufacturability (if industry
not available)
2 7 8 3 3
TOTAL 20 34 38 35 32
3.3 Constraints and Other Considerations
The primary constraint is to design and develop chassis towards the rules and
regulations created for the competition. These rules provide system level standards that need
to be followed.
3.3.1 Rule Requirement
The FSAE rules are based on safety and minimum required structural reliability and
hence it was paramount to follow these rules. The chassis rules are mentioned as follows:
3.3.1.1 Definitions of Rules considered in FSAE chassis designing:
1 Main Hoop - A roll bar located alongside or just behind the driver’s torso.
2 Front Hoop - A roll bar located above the driver’s legs, in proximity to the steering
wheel.
3 Roll Hoops – Both the Front Hoop and the Main Hoop are classified as “Roll Hoops”.
4 Roll Hoop Bracing Supports – The structure from the lower end of the Roll Hoop
Bracing back to the Roll Hoop(s).
5 Frame Member - A minimum representative single piece of uncut, continuous tubing.
6 Frame - The “Frame” is the fabricated structural assembly that supports all functional
vehicle systems. This assembly may be a single welded structure, multiple welded
structures or a combination of composite and welded structures.
7 Primary Structure: The Primary Structure is comprised of the following Frame
components:1) Main Hoop, 2) Front Hoop, 3) Roll Hoop Braces and Supports,4) Side
Impact Structure, 5) Front Bulkhead, 6) Front Bulkhead Support System and 7) all
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Frame Members, guides and supports that transfer load from the Driver’s Restraint
System into items 1 through 6.
8 Major Structure of the Frame – The portion of the Frame that lies within the envelope
defined by the Primary Structure. The upper portion of the Main Hoop and the Main
Hoop Bracing are not included in defining this envelope.
9 Front Bulkhead – A planar structure that defines the forward plane of the Major
Structure of the Frame and functions to provide protection for the driver’s feet.
10 Impact Attenuator – A deformable, energy absorbing device located forward of the
Front Bulkhead.
11 Side Impact Zone – The area of the side of the car extending from the top of the floor
to 350 mm (13.8 inches) above the ground and from the Front Hoop back to the Main
Hoop.
12 Node-to-node triangulation – An arrangement of frame members projected onto a
plane, where a co-planar load applied in any direction, at any node, results in only
tensile or compressive forces in the frame members. This is also what is meant by
“properly triangulated”.
3.3.2 Chassis Rules:
3.3.2.1 Main and Front Roll Hoops
a. The driver’s head and hands must not contact the ground in any rollover attitude.
b. The Frame must include both a Main Hoop and a Front Hoop
c. When seated normally and restrained by the Driver’s Restraint System, the helmet of a
95th percentile male (anthropometrical data) and all of the team’s drivers must:
d. Be a minimum of 50.8 mm (2 inches) from the straight line drawn from the top of the
main hoop to the top of the front hoop.
e. Be a minimum of 50.8 mm (2 inches) from the straight line drawn from the top of the
main hoop to the lower end of the main hoop bracing if the bracing extends rearwards.
f. Be no further rearwards than the rear surface of the main hoop if the main hoop bracing
extends forwards.
g. The 95th percentile male template will be positioned as follows:
h. The seat will be adjusted to the rearmost position.
i. The pedals will be placed in the most forward position.
j. The bottom 200 mm circle will be placed on the seat bottom such that the distance
between the center of this circle and the rearmost face of the pedals is no less than 915
mm (36 inches).
k. The middle 200 mm circle, representing the shoulders, will be positioned on the seat
back.
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l. The upper 300 mm circle will be positioned no more than 25.4 mm (1 inch) away from
the head restraint (i.e. where the driver’s helmet would normally be located while
driving).
3.3.2.2 Main Hoop :
a. The Main Hoop must be constructed of a single piece of uncut, continuous, closed
section steel tubing.
b. The use of aluminium alloys, titanium alloys or composite materials for the Main Hoop
is prohibited.
c. The Main Hoop must extend from the lowest Frame Member on one side of the Frame,
up, over and down the lowest Frame Member on the other side of the Frame.
d. In the side view of the vehicle, the portion of the Main Roll Hoop that lies above its
attachment point to the Major Structure of the Frame must be within ten degrees (10°) of
the vertical.
e. In the side view of the vehicle, any bends in the Main Roll Hoop above its attachment
point to the Major Structure of the Frame must be braced to a node of the Main Hoop
Bracing Support structure with tubing meeting the requirements of Roll Hoop Bracing.
f. In the front view of the vehicle, the vertical members of the Main Hoop must be at least
380 mm (15 inch) apart (inside dimension) at the location where the Main Hoop is
attached to the Major Structure of the Frame.
3.3.2.3 Front Hoop :
a. The Front Hoop must be constructed of closed section metal tubing.
b. The Front Hoop must extend from the lowest Frame Member on one side of the Frame,
up, over and down to the lowest Frame Member on the other side of the Frame.
c. With proper gusseting and/or triangulation, it is permissible to fabricate the Front Hoop
from more than one piece of tubing.
d. The top-most surface of the Front Hoop must be no lower than the top of the steering
wheel in any angular position.
e. The Front Hoop must be no more than 250 mms (9.8 inches) forward of the steering
wheel. This distance shall be measured horizontally, on the vehicle centreline, from the
rear surface of the Front Hoop to the forward most surface of the steering wheel rim with
the steering in the straight-ahead position.
f. In side view, no part of the Front Hoop can be inclined at more than twenty degrees
(20°) from the vertical.
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3.3.2.4 Main Hoop Bracing :
a. Main Hoop braces must be constructed of closed section steel tubing.
b. The Main Hoop must be supported by two braces extending in the forward or rearward
direction on both the left and right sides of the Main Hoop.
c. In the side view of the Frame, the Main Hoop and the Main Hoop braces must not lie on
the same side of the vertical line through the top of the Main Hoop, i.e. if the Main Hoop
leans forward, the braces must be forward of the Main Hoop, and if the Main Hoop leans
rearward, the braces must be rearward of the Main Hoop.
d. The Main Hoop braces must be attached as near as possible to the top of the Main Hoop
but not more than 160 mm (6.3 in) below the top-most surface of the Main Hoop. The
included angle formed by the Main Hoop and the Main Hoop braces must be at least
thirty degrees (30°).
e. The Main Hoop braces must be straight, i.e. without any bends.
f. The attachment of the Main Hoop braces must be capable of transmitting all loads from
the Main Hoop into the Major Structure of the Frame without failing. From the lower
end of the braces there must be a properly triangulated structure back to the lowest part
of the Main Hoop and the node at which the upper side impact tube meets the Main
Hoop. This structure must meet the minimum requirements for Main Hoop Bracing
Supports or an SES approved alternative. Bracing loads must not be fed solely into the
engine, transmission or differential, or through suspension components.
g. If any item which is outside the envelope of the Primary Structure is attached to the
Main Hoop braces, then additional bracing must be added to prevent bending loads in
the braces in any rollover attitude.
3.3.2.5 Front Hoop Bracing :
a. Front Hoop braces must be constructed of material.
b. The Front Hoop must be supported by two braces extending in the forward direction on
both the left and right sides of the Front Hoop.
c. The Front Hoop braces must be constructed such that they protect the driver’s legs and
should extend to the structure in front of the driver’s feet.
d. The Front Hoop braces must be attached as near as possible to the top of the Front Hoop
but not more than 50.8 mm (2 in) below the top-most surface of the Front Hoop.
e. If the Front Hoop leans rearwards by more than ten degrees (10°) from the vertical, it
must be supported by additional bracing to the rear. This bracing must be constructed of
material.
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Figure 3.3- Helmet Clearance
3.3.2.6 Other Bracing Requirements :
a. Where the braces are not welded to steel Frame Members, the braces must be securely
attached to the Frame using 8 mm Metric Grade 8.8 (5/16 in SAE Grade 5), or stronger,
bolts. Mounting plates welded to the Roll Hoop braces must be at least 2.0 mm (0.080
in) thick steel.
b. The minimum radius of any bend, measured at the tube centreline, must be at least three
times the tube outside diameter. Bends must be smooth and continuous with no evidence
of crimping or wall failure.
c. The Main Hoop and Front Hoop must be securely integrated into the Primary Structure
using gussets and/or tube triangulation.
3.3.2.7 Other Side Tube Requirements :
If there is a Roll Hoop brace or other frame tube alongside the driver, at the height of the
neck of any of the team’s drivers, a metal tube or piece of sheet metal must be firmly
attached to the Frame to prevent the drivers’ shoulders from passing under the roll hoop
brace or frame tube, and his/her neck contacting this brace or tube.
3.3.2.8 Frontal Impact Structure :
a. The driver’s feet and legs must be completely contained within the Major Structure of
the Frame. While the driver’s feet are touching the pedals, in side and front views no
part of the driver’s feet or legs can extend above or outside of the Major Structure of the
Frame.
b. Forward of the Front Bulkhead must be an energy-absorbing Impact Attenuator.
3.3.2.9 Bulkhead :
a. The Front Bulkhead must be constructed of closed section tubing.
b. The Front Bulkhead must be located forward of all non-crushable objects, e.g. batteries,
master cylinders, hydraulic reservoirs.
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c. The Front Bulkhead must be located such that the soles of the driver’s feet, when
touching but not applying the pedals, are rearward of the bulkhead plane. (This plane is
defined by the forward-most surface of the tubing.) Adjustable pedals must be in the
forward most position.
3.3.2.10 Front Bulkhead Support :
a. The Front Bulkhead must be securely integrated into the Frame.
b. The Front Bulkhead must be supported back to the Front Roll Hoop by a minimum of
three (3) Frame Members on each side of the vehicle with one at the top (within 50.8
mm (2 inches) of its top-most surface), one (1) at the bottom, and one (1) as a diagonal
brace to provide triangulation.
c. The triangulation must be node-to-node, with triangles being formed by the Front
Bulkhead, the diagonal and one of the other two required Front Bulkhead Support Frame
Members.
d. All the Frame Members of the Front Bulkhead Support system listed above must be
constructed of closed section tubing.
3.3.2.11 Side Impact Structure :
a. The Side Impact Structure for tube frame cars must be comprised of at least three (3)
tubular members located on each side of the driver while seated in the normal driving
position.
Figure 3.4- Side Impact member
b. The locations for the three (3) required tubular members are as follows:
c. The upper Side Impact Structural member must connect the Main Hoop and the Front
Hoop. With a 77kg (170 pound) driver seated in the normal driving position all of the
member must be at a height between 300 mm (11.8 inches) and 350 mm (13.8 inches)
above the ground. The upper frame rail may be used as this member if it meets the
height, diameter and thickness requirements.
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d. The lower Side Impact Structural member must connect the bottom of the Main Hoop
and the bottom of the Front Hoop. The lower frame rail/frame member may be this
member if it meets the diameter and wall thickness requirements.
e. The diagonal Side Impact Structural member must connect the upper and lower Side
Impact Structural members forward of the Main Hoop and rearward of the Front Hoop.
f. With proper gusseting and/or triangulation, it is permissible to fabricate the Side Impact
Structural members from more than one piece of tubing.
g. Alternative geometry that does not comply with the minimum requirements given above
requires an approved “Structural Equivalency Spreadsheet”.
3.3.2.12 Cockpit Opening :
In order to ensure that the opening giving access to the cockpit is of adequate size, a
template shown in Figure .will be inserted into the cockpit opening. It will be held
horizontally and inserted vertically until it has passed below the top bar of the Side
Impact Structure (or until it is 350 mm (13.8 inches) above the ground for monocoque
cars). No fore and aft translation of the template will be permitted during insertion.
Figure 3.5- Cockpit Opening
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3.3.2.13 Cockpit Internal Cross Section :
A free vertical cross section, which allows the template shown in Figure..to be
passed horizontally through the cockpit to a point 100 mm (4 inches) rearwards of the
face of the rearmost pedal when in the inoperative position, must be maintained over its
entire length. If the pedals are adjustable, they will be put in their most forward position.
Fig.3.6 : Cockpit Template
3.3.2.14 Jacking Point:
A jacking point, which is capable of supporting the car’s weight and of engaging the
organizers’ “quick jacks”, must be provided at the rear of the car. The jacking point is required
to be:
a. Visible to a person standing 1 meter (3 feet) behind the car. Painted orange.
b. Oriented horizontally and perpendicular to the centerline of the car.
c. Made from round, 25 – 29 mm (1 – 1 1/8 inch) O.D. aluminum or steel tube
d. A minimum of 300 mm (12 inches) long
e. Exposed around the lower 180 degrees (180°) of its circumference over a minimum
length of 280 mm (11 in)
f. The height of the tube is required to be such that: - There is a minimum of 75 mm (3 in)
clearance from the bottom of the tube to the ground measured at tech inspection. - With
the bottom of the tube 200 mm (7.9 in) above ground, the wheels do not touch the
ground when they are in full rebound.
g. Access from the rear of the tube must be unobstructed for at least 300mm of its length.
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3.3.2.15 Minimum material requirement :The FSAE rules also specifies the minimum
thickness of material required for the frame members as follows:
3.3.3 Function of Chassis:
1 The concept of chassis carries several different connotations, depending on its area of
application. In this project, the chassis is interpreted as the primary structure of FSAE
race car, which carries and connects all systems and components.
2 It is essentially the foundation of the race car. Being the primary structure, the chassis
has the fundamental duties of supporting the weight of all components of the race car
and taking loads resulted from longitudinal, lateral and vertical accelerations of the
race car during its operation without structural failure.
3 On top of that, the most important role of the chassis is to provide a structural
platform that can connect the front and rear suspension without excessive deflection.
The chassis plays a highly significant role for the performance of the race car.
4 Other duties of the chassis include packaging management, driver ergonomics
management and weight management. They also play essential roles in ensuring the
high performance of the race car.
3.3.4Attributes of Chassis :
With the function of chassis identified, there are attributes which the chassis has to
possess to perform its duties for FSAE race car. These attributes outline the qualitative
characteristic of the chassis and provide the foundation for the quantitative assessment on its
performance. Following attributes of chassis are by no mean comprehensive as they are
established with specific emphasis on FSAE application:
Table 3.5 – Minimum Material Requirement
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3.3.4.1 Weight: Weight of the race car is critical for its performance. It influences the
acceleration and cornering capability of the race car significantly. Therefore, the chassis,
being one of the main components of the race car, must have the lightest weight possible
in order to assist the race car to achieve the highest possible performance.
3.3.4.2 Structural Strength: Structural strength refers to the capability of the structure
in withstanding loads. A chassis must have high structural strength in order to withstand
high operation loads that are induced by the race car during the racing operation without
structural failure. This attribute is the fundamental property for the chassis in order to
fulfil the functionality requirement.
3.3.4.3 Structural Stiffness: Structural stiffness refers to the capability of the structure
in resisting deformations. A chassis must have high structural stiffness in order to have
minimum deformations upon loading. This attribute plays a significant role in the
performance and safety of the race car. As a structure that houses various vehicle
systems, this attribute ensures that the chassis is stable for these systems to consistently
perform. From the safety perspective, this attribute ensures that the chassis is sufficiently
stiff to provide the survival space needed for the driver when accidents occur.
3.3.4.4 Specific Structural Strength &Stiffness: Specific structural strength refers to
the ratio of the structural strength to the weight of the structure. Likewise, specific
structural stiffness refers to the ratio of the structural stiffness to the weight of the
structure. On top of having high structural strength and stiffness, a chassis must also
have high specific structural strength and stiffness. It is not enough to only have high
strength and stiffness. Focusing on only high strength and stiffness usually leads to
performance compromise for the race car. Therefore, for the race car to be competitive
in the race, the chassis has to have the highest possible specific structural strength and
stiffness. This attribute is basically the combination of above three other attributes. In
practice, this is utilized dominantly for the design and analysis of the chassis because of
its encompassment of other threes. The achievement of this attribute is more significant
than other threes.
3.3.4.5 Crashworthiness: Crashworthiness refers to the capability of a structure in
protecting the occupant in case of accidents. A chassis must be crashworthy in order to
protect the driver from fatality when accidents occur. It must be able to withstand the
impact load and absorb the kinetic energy during impact. This attribute is critical for the
safety of the race car.
3.3.4.6 Durability and Reliability: Durability of the structure refers to the capability of
the structure in carrying out its duties beyond its expected life. Reliability of the
structure refers to the capability of the structure in carrying out its duties with
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consistency within its expected life. A chassis must have both durability and reliability
for the race car to perform competitively in races.
3.3.4.7 Manufacturability and Ease of Manufacture: Manufacturability of the
structure refers to the extent to which the structure can be manufactured at finite
resources. A chassis must have manufacturability. This is the most fundamental attribute
that all structures, including the chassis, must have. There is no purpose in engineering
the best chassis, should there be one, if such a chassis is not feasible to be manufactured
with available resources. Ease of manufacture is important for the chassis. It does not
only help to improve manufacturability, but also help to facilitate small volume
production of the chassis for spare purpose. In practice this attribute is achieved through
proper selection of type of chassis.The manufacturing attributes such as bending radius
for tube and fixtures for précised fitment and welding were considered.
3.3.4.8 Ease of Access, Assembly and Maintenance: Ease of access, assembly and
maintenance are essential for the chassis. These three virtues are closely related to each
other and each is a crucial element for the other. Ease of maintenance aids in the
execution of the maintenance schedules, thus improving the reliability of the race car.
On the other hand, ease of assembly helps to ensure the proper assembly of other
systems to the chassis. This reduces the overall assembly time of the race car and thus
maximizes its track time. In order to obtain ease of maintenance and ease of assembly,
ease of access has to be achieved.
3.3.4.9 Performance Requirement: Structural stiffness and weight of the chassis is the
main spotlight under this requirement because of their strong influence on the
performance of the race car. Often, these two are treated as one entity and specific
structural stiffness is utilized instead so as to approach this requirement in a more
efficient manner. Ideally, specific structural stiffness is to be designed as high as
possible. In practice, this is however impossible. The chassis is designed to have the
highest possible specific structural stiffness within the allocated design time.
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3.3.5 Fundamental Requirement
Structural strength, crashworthiness, durability and reliability of the chassis are the main
interest under this requirement because of their fundamental essentiality in making sure the
functionality of the chassis. This requirement must be met satisfactorily and in practise the
chassis of FSAE race car is designed with several unique tactics for the fulfilment of this
requirement. These assumptions are reviewed in following sections.
3.3.6 Auxiliary Requirement
Manufacturability, ease of manufacture, access, assembly and maintenance of the chassis
are the main attention under this requirement. It must be noted that this auxiliary represents only
a relative difference in importance between this requirement and other requirements in term of
their direct influence on the track performance of the race car. It is still influential to the
performance of the race car in an intangible manner and hence this requirement must be met
adequately in order to ensure those aspect of the race car’s performance is not heavily
compromised. In practise, this requirement is satisfied through packaging management and
thorough planning of the manufacturing of the chassis.
Fig. 3.7: HRT 02 Car
Figure 3.8: Frame design with the major components
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Figure 3.9 : Side view of a preliminary design for the vehicle chass
Figure 3.10 : Top view of the same design
After the initial design for a chassis is developed it must be analyzed. First, the
application for the design must be chosen. Basic translation properties of extreme conditions
are evaluated in order to theoretically test the worse-case scenario and prove the ability of
the chassis design to withstand these idealized conditions. The values used in the 2014
vehicle were simply assumptions since no prior cars were available to conduct actual testing
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and provide more accurate idealized data. Once these guidelines are established, they are
utilized in the analysis of the chassis. Due to the number of frame members associated with
the chassis, numerous equations must be calculated using finite element analysis. Fortunately,
there are many computer programs that can make these calculations and yield values and
images to guide the analysis and allow further development of the design. It was decided to
utilize the simulation package for SolidWorks, which utilizes the distortional energy theory
for finding stress values via static analysis.
Another task during the analysis phase is choosing what will become a fixed point
during simulation and the manner in which the load values are applied. The decision to use
the rear mounting points as a fixture during torsional testing was to allow as much of the
chassis to experience the torsional load as possible. The forces applied to the chassis would
be transmitted from the tires. Therefore, the simulated loading was applied to where the front
control arms were to be mounted to mimic this detail. In addition, there were other specific
tests that FSAE requires. Static testing on the main hoop, front hoop, and side impact bar
was conducted on the chassis by fixing the appropriate points and loading the specified areas
with the required loads.
Primary considerations for analysis are deflection, stress and factor of safety.
Deflection changes the geometry of the car under load and has light effects on the handling of
the car. A benefit to deflection is that it can help improve some aspects of handling and it
provides feedback to the driver just beyond the inertial forces. The most critical aspect of the
chassis design is the stresses distributed throughout the chassis. These stresses will
demonstrate where critical areas are. Redesigning by changing component orientation or
reinforcing can ultimately help reduce the stresses. Sections where low stresses are identified
may contain unnecessary members. Redesigning these overly engineered areas can reduce the
overall weight of the chassis, but it can add to the complexity of geometries and possibly
change the overall price. The factor of safety is generated from the material yield strength
divided by Von Misses stress. This value provides less insight to the design capability, but
shows that the design meets the designer’s safety criteria. The absolute lowest acceptable
value is 1, while a higher value demonstrates better safety.
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3.4 Mathematical Analysis:
The calculation for torsional stiffness :
KT = T/Ө (1)Where,
KT = Structural torsional stiffness
T = FL
F = Force applied
L =Width of measurement
ϴ = tan−1 [(y1 +y2)/ 2L]
ϴ = Angular deflection
y1 =Left vertical displacement
y2 = Right vertical displacement
The torque is derived from the product of the force applied at one corner of the race car and the
distance from the point of application to the centerline of the chassis. The angular deflection is
taken to be the angle formed from the center of the chassis to the position of the deflected
corner. Both left and right vertical displacements are included in the equation to take the
average vertical displacement in order to generate a more accurate estimate of the total angular
deflection of the chassis. Equation (1) is utilized for the assessment of the structural torsional
stiffness of the chassis for its design and analysis. This equation is inputted into the spreadsheet
and graph is plotted to look the coefficient. The coefficient is the structural torsional stiffness,
K*T of the chassis. All values needed for the equation are measured from the chassis model in
SolidWorks.
L = 575 mm = 0.575 m
Y1= 9.22 mm = 9.22 * 10-3 m
Y2 = 8.453 mm = 8.453 * 10-3 m
= tan-1[(y1 +y2)/ 2L ]
= tan-1{[ (9.22 * 10-3 +8.453 * 10-3 )/ (2 * 0.575)]}= 0.880
F= 2000 N
T= FL
= 2000 * 0.575 = 1150 N
KT = T / Ө
= 1150/ 0.88 = 1306.818 Nm/ degree.
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3.5 Prototype1
The chassis and body of the 2015 Formula SAE car is the first prototype that will serve as a
test bench for the 2015 chassis and body produced during the course of this project. This
prototype offers the benefit of being a completely running and driving vehicle, from which all
the vehicle dynamics adjustments and goals will be verified. This vehicle includes thechassis
and body and its interaction with all other vehicle system components, such as braking system,
power train and drive train systems, aero package and full electrical package.
3.5.1 Chassis: The following images show the design and the analysis for the 2015-16 FSAE
Chassis. Some critical aspects to pay attention to are the way the chassis fits the FSAE rules
with the triangulated frame members and the heights of the roll hoops, providing a safety
region for rollover protection. Note that this chassis contains a larger wheelbase of 1535mm.
Within the design for the chassis, the use of node-to-node connections was used to fit the rules
established by FSAE. The triangulated frame elements also allows a wider distribution of
applied and translated stresses throughout the design of the chassis. A final detail is the cockpit
area, which has a significant effect on handling. This area is lower than the front and rear
control arm- mounting areas. This yields a lower center of mass and maintains critical
suspension geometry to allow for optimal handling.
Figure 3.11: Final chassis design side view
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Figure 3.12: Final chassis design top view
The 2015-16 chassis was designed with driver ergonomics and weight reduction from
the previous chassis. The chosen engine was a KTM 390 engine, which provides a relatively
good amount of torque within a while maintaining a light weight. Following this engine
choice, the car needed to be as light as possible to effectively benefit from the motor choice.
The chassis is a completely tubular space frame fabricated with AISI 1018 steel round tubing.
These hoops were designed to provide maximum driver leg room while maintaining the
desired track length, which is the length from the center of the tire on the left side to the
center of the tire on the right side. The front bulkhead was designed to the exterior
dimensions of the standard FSAE impact attenuator. The width of the chassis at the bottom of
the main roll hoop was chosen to provide maximum room from engine and electrical
components as well as to reduce complexity of the chassis in this area by limiting the number
of bends in the main hoop. The designs were made so that the engine can be inserted from the
right side of the chassis, between the main roll hoop and the main roll hoop supports. The
mounting system, which consists of lateral bars stretching the width of the chassis with tabs
mounting to the engine, was
When designing the chassis, the decision was made to minimalize the rear box for
ease of access and servicing of drive train components as well as to reduce weight of the
chassis. The section of bent tubing mounted to the rearward, upper suspension mount is
placed to distribute the load of the suspension as well as to provide a location for mounting of
the shocks, and chain guard. The jacking point was positioned slightly rearward of the last
frame member so it would not interfere with the suspension during travel. Overall the chassis
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weighs approximately 73lbs.
The above figure shows the overhead view of the 2015 HRT FSAE chassis. Some primary
elements to note are the middle of the chassis having wider elements, which gave the design
three primary benefits. The first benefit was that the operator would have more room for
operating the car efficiently, providing more comfort for the driver and allowing for easier
entrance and exit, which is critical in emergency situations. The second advantage would be
structural, which gave more room on chassis members and allowed for better control on
distributed stresses. This design decision also increased potential options for mounting
additionally required equipment. A final benefit was an increase in safety since a side impact to
the chassis had more room to allow for the deflection of the side members to help reduce the
risk of injury for the driver. The front and rear sections of the chassis were reduced in
proportion to the smaller engine size. This also allowed the chassis to have a potential for lower
weight since options for reducing some dimensions.
Viewing the chassis from the front, the side impact zone can be seen as described.
Due to budget constraints the numbers of bends in the chassis were minimized to reduced
total manufacturing costs since the frame cuts, bends and notches were subcontracted to a
fabrication shop. Figure shows how the front impact zone is braced for head-on collision
impacts, where the diagonal member is used as structural support for the required impact
attenuator.
Fig.3.13 : Impact Attenuator
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Figure 3.14: Chassis view from front
The rear view of the chassis shows how triangular orientations of the members
attempt to maximize the number of load bearing members to help assure each element of the
chassis serves a purpose.
These two figures included to help show the design elements previously discussed in
this analysis. Figure 13 shows the weight of the final chassis being 72.28 lbs.
Figure 3.15 : Isometric view of chassis
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Figure 3.16: Mass properties of chassis
3.6 Design requirement
1. It should be light weight and fabricated at a minimal expense.
2. It should be designed for manufacturability.
3.6.1 Fiberglass
a. Fiber glass is a fibres reinforced polymer made of a plastic matrix reinforced with
fine fibres of glass. The glass fibres are made of various types of glass depending
upon the fiberglass use. These glasses all contain silica or silicate, with varying
amounts of oxides of calcium, magnesium, and sometimes boron. Fiberglass is a
strong lightweight material and is used for many products. Although it is not as
strong and stiff as composites based on carbon fibre, it is less brittle, and its raw
materials are much cheaper. Its bulk strength and weight are also better than many
metals, and it can be more readily moulded into complex shapes.
b. The fiberglass employed in this fabrication process is E-glass, which is alumina
borosilicate glass with less than 1% w/w alkali oxides, mainly used for glass-
reinforced plastics.
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CHAPTER 4
FINITE ELEMENT ANALYSIS OF CHASSIS
4.1 FEA Analysis
Figure 4.1 show a front impact test of the chassis where a dynamic load outlined in
the 2015 FSAE rules of 150kN (33721 lbs.) on the front of the chassis was applied.
Displacement of various members in the design can be seen in the following images. The way
the chassis distorts demonstrates the potential for driver safety through a controlled folding of
the chassis rather than a crushing effect. This controlled folding was due to proper
triangulation of the members within thechassis.
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Fig.4.1 : Frontal Impact Analysis of Chassis
Fig.4.2 : Static Deflection of Chassis
Figures 4.2 outline the 2015-16 FSAE rules, where a static loads were placed with
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appropriate magnitudes and specific directions on the front and main hoops, as well as on the
side impact beams of the chassis. Analysis of these members is crucial for understanding how
stress is distributed throughout the system, which is ultimately important when the potential
loss of human life is involved in an engineer’s product. The reason for a static load is not
exactly understood since a dynamic load would better simulate an accident. However, the
general description of static loads can provide insight to a partial of the dynamic potential of
these members.
Fig.4.3 : Torsional Deflection of Chassis
To demonstrate the structural integrity of the chassis, a torsional load was applied on
the front control arms while the area where the rear control arms would be mounted was
fixed. This load is created by a positive static load on one side of the chassis and negative on
the opposite side; which will translate to torsion. This analysis was found to be the most
critical since it defined the reaction of every member throughout the chassis in cornering,
which is vital in any sort of racing that incorporates turning or extremely high torques on the
chassis. Many things can be seen with this analysis that is critical in the design and future
revisions. One of the first things to notice is the stress developed through each member. These
stresses, when combined with the yield strength, show the factor of safety through the design.
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The extremely low and high values of stresses in the design show where design revisions may
be beneficial. In cases with high stresses, reinforcing the area or altering the angles of
members may translate the stresses better throughout the entire structure, which will increase
operator safety. By altering areas where low stresses are found, one can remove members that
will translate those stresses, which will reduce chassis weight.
Figure4.4 : Torsional load on chassis
4.2 Proposed Design
Based on the 2015 FSAE rules, the design of the chassis ultimately starts with an
inward look at the performance of the 2014 FSAE Chassis and suspension. Various series of
testing was done on this prototype to determine whether or not the performance of the chassis
meets the intended design expectations. In addition, testing was necessary to get baseline
results in order to attain a realistic understanding of how to improve on the chassis and
suspension. The previous sections allowed for an understanding of the logic that was behind
the final design of the 2014 chassis and suspension, which is the same logic used in the
design of the 2015 vehicle. The 2015 chassis and suspension serves as an updated iteration in
design, meant to conform to the new rules released by SAE International for the 2015
competition, improve on design and performance issues observed in the 2014 competition,
and provide and overall improvement in performance and cost.
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CHAPTER 5
MANUFACTURING AND VERIFICATION
5.1 Chassis
5.1.1Ergonomic Integration
Integration of ergonomics is very important during the development of a Formula SAE
chassis. There was heavy consideration of driver placement due to the nature of tight
packaging and weight distribution. Placing the driver as low as possible to affect the
center of gravity was integral in performance based ergonomic decisions. Other factors,
such as driver comfort and component accessibility forced some of the decisions as
well. At competition, the judgment of ergonomics is based on the aforementioned
factors and adheres strictly to the rule book. Furthermore, the Marshalls place the
95thpercentile male template (see Figure 45) as one of the technical inspection tests.
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Figure 5.1 : 95th percentile male template [7]
In order to take driver integration into the chassis a bit further than simply integrating
the rule book template, an ergonomics rig was manufactured. This rig can simulated driver
positions as well as firewall angle, steering wheel placement and pedal placement for comfort
ability (see Figure 5.2).
Figure 5.2 : Ergonomics rig
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The rig was created using plywood and two-by-four wood pieces for simplicity and
cost. Three major dimensions are taken into consideration: angle of the drivers back,
angle and steering wheel placement and pedal distance. Besides considering the 95th
percentile male model, a few SAE team members sat in the rig and a driver’s envelope has
created.
Figure 5.3 : 3-D driver
After driver envelope was created, the integration process can begin. This continued
to evolve the frame design to the final versions. The steel tubular shape frame is designed to
house all ergonomic components.
Figure 5.4 : Integration of ergonomic test plates and chassis design
Figure 5.4 also demonstrates how the pedals and both technical inspection templates
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were placed in the frame. If necessary, refer to the FSAE rule book in the appendices for
more information on templates. Other components, such as the powertrain system towards the
rear of the vehicle, were also integrated. With all these components properly packaged,
finalization of the design followed. Other rule considerations were also taken into account. As
seen in Figure 49, the helmet lines from the front roll hoop to the main roll hoop were taken
into consideration in order to pass another of the technical inspection tests.
Figure 5.5: Side-view of ergonomic test plates and chassis
5.2 Frame Improvements
After construction, implementation of an ergonomics rig and correction of the several
issues that arose, the chassis was modified to improve the fitment of a 95thpercentile driver.
The engine compartment was made significantly smaller, the front bulkhead was extended by
4 inches, the front roll hoop was brought closer to the driver to allow for better placement of
the steering wheel and eliminate the severe angle placed on the steering column (which
created a binding issue on the steering system), and the rear box was eliminated. The front
bulkhead support was designed using thinnest tubing allowed by the rules, with a thickness of
0.045 inches, a method of weight reduction, which was not ventured in the first prototype.
The combination of these changes resulted in a chassis of 54.63 lbs., which is 30% lighter
than the previous prototype. The new design is shorter in overall length, with a longer nose to
accommodate the driver, and much narrower, resulting in the need for more effective
packaging of several components. In order to accomplish this, as well as provide a better
ergonomic seating position for the driver, the mounting locations for several components
such as the fuel tank, ECU, and catch cans have relocated making the most of the available
space. The abovementioned components are now packaged beneath the seat’s inclined
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backrest allowing for tighter packaging of the power train. The relocation of these
components combined with a new, in-depth engine model allowed for the reduction in size of
the engine compartment itself. This, along with the elimination of the rear box, has been
critical in the lightening of thechassis.
Fig.5.6: Tube Profiling of chassis members
Fig : Fixtures for Chassis Structure
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Fig. 5.8 :Weldments at Joints
Fig.5.9 : Final Structure of Chassis
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Figure 5.10: Prototype 1 and 2 up and down. The red color denotes the updated
prototype 2.
When designing a chassis, there is an importance placed on the geometry of the
suspension and the triangulation of the frame members that hold the suspension connecting
points. All of the forces generated from the road and tire will be directed to the frame through
these points. Due to this, in redesigning rear suspension geometry, the rear section of the
prototype necessitated changing.
Figure 5.11: Isometric view of both body prototypes. The grey color denotes
prototype II
5.3 Manufacturing of Body Panels
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5.3.1 Mould
Poly Urethane Foam were used as the primary material to make the mold.
5.3.2 Fabrication of the body panel
The body panel was designed in three parts- two side panels and a nose. The nose was
further divided into two parts to simplify the manufacturing process. These two parts were
separately manufactured and joined together to form the complete nose. The manufacturing
process of open moulding was selected to manufacture FRP body panel.
To obtain a smooth surface for the body panel it was decided to make a positive (male)
mould. For the two side panels and middle cover, PU foam were used to make the mould. The
dimensions of the sheet to be cut were determined for the solidwork model of the vehicle. It was
bent manually as per the design and very minor modifications were made after some hit and trial
fitment with the chassis.
5.3.3 Laying Process
Fig. 5.12: Laying Process of FRP
Hand lay-up process is used for the production of parts of any dimensions such as technical
parts with a surface area of a few square feet. But this method is generally limited to the
manufacture of parts with relatively simple shapes that require only one face to have a smooth
appearance (the other face being rough from the moulding operation). It is recommended for
small and medium volumes requiring minimal investment in moulds and equipment.
The contact moulding method consists of applying these elements successively onto a mould
surface:
- a release agent,
- a gel coat,
- a layer of liquid thermosetting Resin, of viscosity between 0.3 and 0.4 Pas, and of medium
reactivity,
- a layer of reinforcement(glass, aramid, carbon, etc.) in the form of chopped strand Mat or
woven Roving
Impregnation of the reinforcement is done by hand using a roller or a brush.
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This operation is repeated for each layer of reinforcement in order to obtain the
desired Thickness of the structure.
Fig.5.13 : Machining of Poly Urethane Foam For mould
Fig.5.14 : Foam ready for laying
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Fig.5.15 : Laying Process of Fiberglass
Fig5.16 : Final Painting of Body
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CHAPTER 6
CONCLUSION AND FUTURE RECOMMENDATION
6.1 Conclusion
1. The design was accurate complying fairly with the rules and regulations of the
rulebook. It incorporated the safety and aesthetics in the vehicle and the most optimal
design fulfilling all the pre- requisite objectives were attained after sufficient periodic
iterations.
2. FRP was selected as the material for making the body panels as it turned out to be the
most optimal choice among the alternatives abiding the constraints and meeting the
requirements.
3. The fabrication of the mold and body panel turned out to be simple, cost effective
but time consuming.
6.2 Future Recommendations
In addition to being an engineering exercise, the formula SAE competition is about
making an exhilarating formula style car that would entice a customer to purchase a ride .
The key to improvisation is the analysis and critical testing of the present design and
products. This opens the gates for further modification to improve the product's cost
effectiveness, ease of manufacturability, durability, aesthetics, ergonomics etc.
The first thing the potential customer sees is the body. The use of FRP in this manufacturing
process has many advantages. It provides a strong scratch resistant surface which is easy to
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install, maintain and repair. It is light weight, provides sufficient strength and can be
fabricated using simple tools. However, manufacturing the body panels by Hand- layup open
moulding process is clumsy and time consuming. The same limitation applies in manually
manufacturing of moulds.
Mould making process can be done more effectively using CNC machine, 3-D printing etc
by using more durable moulding materials. It would provide accurate tolerances and exact
shapes enhancing its workability. Similar improvements in the technique, materials and
manufacturing methods of FRP would yield better results.
The body panel of the FSAE race car is still an unexploited domain where several
opportunities for innovations and improvements lie. FRP has also a vast potential not only in
the automobile industry but in all spheres of technological advancements.
In future, additional consideration should also be given to the aerodynamic loads as well as
the refinement of design for the ease of manufacture with a very serious consideration.
6.3 Results
Table 6.1 : Result table of iterated Chassis
Chassis no. Displacement
(mm)
Weight
(kg)
Torsional Rigidity
(Nm/ deg)
1.1 15.6 34.749 741.67
1.2 14.66 31.758 787.67
1.3 12.53 31.791 921.47
1.4 12.40 32.088 931.17
1.5 12.44 32.378 928.16
1.6 12.44 32.189 930.11
1.7 11.89 31.889 970.78
1.8 11.82 30.475 976.53
1.9 8.78 33.190 1314.56
1.10 8.026 31.44 1438.04
1.11 7.08 32.542 1630.16
1.12 9.22 29.170 1306.81
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CHAPTER 7
REFERENCES
Thesis
1. Andres Tremante, 2014, "FSAE chassis and suspension report", thesis, International
University, Florida, United States of America.
Journal Paper
2. A.J.Remna,2011, " Design of tubular steel space frame for a formula student race car
", CST 2011.002, Eindhoven University of Technology, United States of America.
3. AkashSood, Padam Singh, Nov 2015,"Analysis of space frame of formula SAE at
high speed with ergonomics and cut m vibration factors", IJMET, Volume 6, Issue ll,
pp.202-212.
4. Thompson, L.L, Law, E. Harry and Lampert, Jon, “Design of a Twist Test Fixture to
Measure Torsional the Torsional Stiffness of a Winston Cup Chassis”, SAE Paper
983054
Technical Paper
5. William.B.Riley, Robert.r.George, 2002, "Design, analysis and testing of a formula
SAE car chassis", Cornell University, United States of America.
Books
6. Formula Student Of Automotive Engineers, Rule Book 2015-16
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7. Milliken, William F. and Milliken, Douglas L., , 1997Book, “Race Car Vehicle
Dynamics”, Society of Automotive Engineers.
Page 63
Acknowledgement
It gives us immense pleasure to express deep sense of gratitude to our guide, Prof. Vinayak
Khatawate, Professor Department of Automobile Engineering for his wholehearted and
invaluable guidance throughout the project and for accepting us as his student.
We take this opportunity to sincerely thank our HOD Dr. Dhanraj P. Tambuskar,
Automobile Engineering. We are also grateful for his support and guidance.
We would like to sincerely thank Dr. R.I.K. Moorthy, Principal for his support.
We are also grateful to all the faculties of Mechanical Engineering Department of Pillai
Institute of Information Technology, New Panvel.
Finally we would like to thank our friends and family members for their help and
encouragement.
(Dhaval Patel) (Yogesh Dhakan)
(BE 826) (BE 808)
(Hanisha Singh Rao) (Sukhdeep Singh Panesar)
(BE 832) (BE 825)