5.blackbook final

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

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)

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:

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:

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)

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

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

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

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

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

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.

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

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

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.

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

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

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.

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

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.

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

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

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

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

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

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

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.

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.

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.

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.

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.

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

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.

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

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

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.

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

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

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.

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.

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

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

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

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

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.

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.

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

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.

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.

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.

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

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

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

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

Fig. 5.8 :Weldments at Joints

Fig.5.9 : Final Structure of Chassis

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

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.

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

Fig.5.15 : Laying Process of Fiberglass

Fig5.16 : Final Painting of Body

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

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

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

7. Milliken, William F. and Milliken, Douglas L., , 1997Book, “Race Car Vehicle

Dynamics”, Society of Automotive Engineers.

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)

5.blackbook final

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