MA

ST

ER

THESIS

Master's Programme in Mechanical Engineering, 60 credits

Design and Construction of Chassis for Uniti L7evehicle

Anoop Bharadwaj Yellambalse Prem Kumar, Pavan KumarMaareddygari

Master Thesis 15 credits

Halmstad 2016-12-30

i

PREFACE

The following Thesis report is an important scholarly achievement that should be presented

with pride, which has been prepared by ANOOP BHARADWAJ and PAVAN KUMAR

MAAREDDYGARI as part of the completion of the master’s education in Mechanical

Engineering, Halmstad University. This report is a product of all the knowledge gained during

our study in this honorable institute and our past bachelors education.

Several persons have contributed academically, practically and with support to this master

thesis. We would therefore firstly like to thank our University Supervisor Dr. Lars Bååth and

Industrial supervisor, Mr. Michel Bano, Head of Research and Development at Uniti Sweden

AB, for their time, valuable input and support throughout the execution of master thesis.

Furthermore, we would like to thank Mr. Lewis Horne CEO Uniti Sweden AB and Dr. Bengt-

Göran Rosén Examiner for their big help throughout the entire process of find the Master’s

thesis.

Finally, we would like to thank our family and friends for being helpful and supportive during

our time studying Master’s in Mechanical Engineering at Halmstad University.

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ABSTRACT

Chassis is the primary structural component of an automobile. It is the main supporting

structure of a vehicle to which all other systems like braking, suspension and differential are

attached. In this thesis, a methodology for L7e category vehicle chassis design and structural

stability analysis is presented. The present car being developed at Uniti Sweden AB is classified

as L7e category vehicle as per the European Union, therefore the chassis developed in this

thesis considers the specific characteristics that vehicles under this category demands for.

A literature study is carried out to review various existing designs of vehicle chassis, latest

innovations and advanced materials used to manufacture the same. The various types of forces

and stresses commonly acting on chassis structures are analyzed and their effects on the

vehicle is understood. After completing literature study, several findings are listed in a

systematic manner, by providing ample arguments to justify each of them. The pro-con analysis

is conducted to evaluate merits and demerits of each alternative type of chassis and the material

to manufacture it. The most essential design criteria are derived from the QFD (Quality

function deployment) which then acts as important guidelines during the actual design process.

Structural chassis frame is designed as per the design criteria, using the CAD software

CATIAV5R19 and the structural stability of the same is tested and analyzed using ANSYS 15.0

software. From the results of these analysis tests the static structural stability of the design is

confirmed.

Keywords: L7e category European Vehicle, Uniti Sweden AB, Pro-con analysis, QFD (Quality

function deployment), CAD software CATIAV5R19, ANSYS 15.0 software, static structural

stability.

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CONTENT

CHAPTER 1: INTODUCTION……….……………………………...…..1

1.1 Background………………………………………………………………………..….1

1.2 Aim of the Study……………………………………………………………….……..2

1.2.1 Problem Definition ……………………………………....…………...…….......…..2

1.3 Limitations……………………………………………………………………......…..2

1.4 Individual Responsibility and efforts during the Project………………………..……2

1.5 Overview of the Company…………………………………………………………....3

CHAPTER 2: METHODOLOGY…………..………………...…………..4 2.1 Alternative Methods…………………………………………………………….…….4

2.2 Chosen methodology for this project…………………………………………………5

2.3 CES EduPack…………………………………………………………………………6

2.4 Preparation and Data collection………………………………………...…………….7

CHAPTER 3: THEORY………………….....……………….……………8

3.1 Chassis Types…………………………………………………………………...…….8

3.2 Types of Stresses acting on the Chassis……………………………….......………...13

3.3 Material Selection…………………………………………………………………...15

3.3.1 Materials used for chassis manufacturing……………………………………..15

3.3.2 Advanced materials…………………………………………….......………….16

CHAPTER 4: RESULTS……………………………….……………..…18 4.1 House of Quality for Types of chassis…………………………………………...….18

4.1.2 Pro- Con Analysis for the types of chassis…………………………………….21

4.2 House of Quality for Material Selection……………………………………….………..23

4.2.1 Pro Con Analysis for material selection………………………………….……26 4.3 Design of Chassis……………………………………………………………………29 4.4 Analysis of Chassis………………………………………………...………………..32 4.5 Static Structural Analysis………………………………………………………..…..34

CHAPTER 5: CONCLUSION…………………………………………..35 CHAPTER 6: CRITICAL REVIEW………………………………..…..36 CHAPTER 7: REFERENCES…………………………………….……..38 CHAPTER 8: APPENDEX………………………………………………40 List of figures……………………………………………………………………………78 List of Tables…………………………………………………………………..………..78

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CHAPTER 1: INTODUCTION 1.1 Background

The word chassis was derived from the Middle French Chaciz, from chasse in the year 1864.

A chassis is a physical frame or structure of an automobile, an airplane, a desktop computer, or

any other multi-component device. In simple words, something leftover when body is removed

from a vehicle is called “chassis”. It is the main supporting structure of a vehicle to which all

other components are attached, and it can be comparable to the skeleton of a living organism.

The components of the vehicle like transmission system, axles, wheels, tyres, suspension,

controlling system like braking, steering, etc., and even electrical systems are mounted on the

chassis frame. Chassis is the main mounting for all the components including the body. So, it

is also called as the ‘Carrying unit’ and the Backbone of a vehicle.

Until 1930’s, virtually every vehicle had a structural frame, separate from the cars body. This

construction design is known as “body- on- frame”. Since then, nearly all passenger cars have

received Uni-body construction, meaning their chassis and bodywork has been integrated into

one another. The last United Kingdom mass-produced car with separate chassis was Triumph

Herald, which was discontinued in 1971. However, nearly all trucks, busses, and pickups,

continue to use a separate frame as their chassis.

The objective of this project is to design and construct a chassis for an L7e CP vehicle called

Uniti. This new conceptual car aims to revolutionize the way cars are made, as cars of today

are outdated as they have been made in the same way from decades. To design a chassis for

Uniti car, we have carried out a detailed study about the various theories of chassis. We have

listed the various types of load conditions, types of stresses acting on a vehicle frame, the

different type of requirements a chassis design must meet. In addition, we also studied about

the different types of chassis existing in the car industry.

As the car being developed is an electric car of L7e CP category, as per the European Union

regulation on approval of L-Category Vehicles it follows some of the constraints as listed

below:

It is a Heavy quadric-mobile (four wheels) vehicle.

Its maximum power should not exceed more than 15 KW.

It has a maximum design speed restricted to 90 km/h.

And with an enclosed passenger compartment that can accommodate maximum of four

non-straddle seats.

The chassis is designed by the CAD/CAM software CATIA V5R19 which is a 3D CAD, CAM,

and CAE platform for product development. It combines the industrial and mechanical design,

simulation, collaboration, and machining in a single package. The tools in this software enable

fast and easy exploration of ideas with an integrated concept-to production toolset.

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1.2 Aim of the Study

The main aim of the project is to design a chassis for Uniti L7e vehicle, which is a new type of

an electric car being developed by the company Uniti, by considering all the different aspects

of environmental sustainability. We also aim to analysis the stresses acting on our design with

stress analysis software.

a) Selecting the best chassis type from the existing types of chassis so that it

suits the design requirement of the Uniti car.

b) Selecting the best material for the chassis of Uniti car, that can answer light

weight features.

c) Designing the chassis as per the design requirements of the L7e CP category

vehicle using the CAD (Computer Aided Design) software CATIA V5 R19

d) Analysing the developed chassis design using the simulation software

ANSYS 15.0 to check for structural stability.

1.2.1 Problem Definition

An ideal chassis is to be designed and developed for the prescribed vehicle such that the design

meets all the stated design criteria thus proving to be structurally stable. The CAD model and

the analysis reports of the same are the deliverables of the project. 1.3 Limitations

The present thesis is intended to provide a suitable design for a chassis for the lightweight

vehicle described above. While it includes a finite element analysis that confirms the suitability

of said design and material selection, the final manufactured product may need to be further

adjusted to satisfy some real-world requirements that are difficult to model or assess ahead of

physical testing.

The design and construction of chassis for a vehicle is a very complex process which usually

involves many iterations and great scrutiny to achieve ideal results. Considering this a thesis

project, adhering to the design standards found in the industry is unrealistic, especially

regarding deadlines. Therefore, the main contribution of this thesis is the capturing of design

requirements and customer preferences through QFD and their translation into numerical target

specifications and the formulation of a chassis design that fulfils these targets. The simulation

step is provided as confirmation that said targets have been met.

1.4 Individual Responsibility and efforts during the Project

All the different aspects listed in the problem definition of this project were undertaken after

thorough discussion and understanding of all the concepts behind each part of the project. Both

team members have shared responsibility equally in all required tasks. The various topics

discussed in the following thesis are based on the literature review, which consisted in the

analysis of various technical articles and textbooks, and is supplemented by the knowledge

gained previously from past courses.

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1.5 Overview of the Company

Uniti Sweden AB is a start-up company established in the early 2016, and whose goal is to

create an innovative and futuristic electric car that is environmentally sustainable provides a

great driver experience. Uniti is currently in the developmental stage in Pro-lab at Lund

University. The Company aims to launch its first model by the year 2018.

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CHAPTER 2: METHODOLOGY

2.l Alternative Methods

The project is about the design and construction of the chassis for the Uniti L7e vehicle, which

requires basic knowledge about the various types of existing chassis or frame designs and the

materials used for their manufacture, as well as the current trends of the automotive Industry.

As this is a product development project, we have made use of all the different stages of product

development referred to in David G. Ullman’s ‘The Mechanical Design Process’. The following

set of design phases are the sources of alternative methods to interact with a problem solution.

Product Discovery:

The project has been initiated to find the best suitable design for the construction of the chassis

of the Uniti L7e Vehicle. In this stage, we also investigate the best suitable material for the

manufacture of the chassis as well as identify the most suitable chassis frame.

Project Planning:

The planning is done to make the product, so that all the various stage of product development

is implemented correctly so that the best solution of product development could be achieved to

finally build a proto type of the chassis design.

Product definition:

All the dimensional specifications of the final design should be finalized with consultations

with both Industrial and University supervisors such that the design meets the design criteria.

QFD is a strategical technique used to identify customers for the product, generating customer

requirements and converting to a technical specification, evaluating the completion and

prioritize the system specifications as for customers of the product.

Conceptual Design:

This design is generated by using the results of QFD, Pro-Con and brainstorming. The chassis

is to be developed, designed, and analyzed such that it can be perfectly suitable for the comfort

of Uniti car users.

Product Development:

This stage involves the development of the QFD in which different concepts are compared until

the best suitable design is implemented. This is the best concept for each function is further

selected and evaluated from an entirely new product. But this approach is not selected for this

project, as no new product is being developed, instead, an existing system is modified.

Product Support:

The Final design of the chassis shall be the property of the company Uniti Sweden AB and all

aspects of product support will also be dependent on the company.

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2.2 Chosen methodology for this project

The project is to design and develop a chassis for Uniti L7eCP vehicle, for which the

methodology is applied in figure below.

Fig:2.2.1 Flowchart of the project

Start

Literature Review:

Types of existing chassis designs.

Types of existing materials for chassis

construction

Recent innovations and trends in chassis

engineering and automotive industry.

Pro-Con Analysis for selection of

ideal chassis design

Pro-Con Analysis for Selection

of ideal material

Justification of Material

selection by CES EduPack

software

QFD for Selection of Chassis

Design and Material

Select Chassis

Design

Select Material for

Chassis

Construction

Design and Analysis

Discussion and

Conclusion

Report generation

End

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(a) Literature review

All basic information required to go ahead with the project is collected and reported in

Chapter 3, which include theory of automobile chassis types, different designs, different

materials, and advanced materials for manufacturing.

(b) Pro-Con Analysis

Pro-con Analysis is a common problem solving technique which frequently requires

decision making which is important to improve quality of decisions. Problem-solving and

decision-making are closely linked, and each requires creativity in identifying and developing

options, for which the brainstorming technique is particularly useful. Good decision-making

requires a mixture of skills: creative development and identification of options, clarity of

judgement, firmness of decision, and effective implementation.

(c) QFD (Quality function Deployment)

The Quality Function Deployment process begins with identifying who the customers

are (step 1) and what they want the product to do (step 2). In developing this information, we

also determine to whom the what is important - an analysis of who versus what (step 3). Then,

it is important to identify how the problem is solved, in other words, what the competition is

for the product being designed (step 4). This information is then compared to what the customer

desires- now versus what (step 4 continued) - to find out where there are opportunities for an

improved product.

Next comes one of the most difficult steps in developing the house of quality in determining

how (step 5) you are going to measure the product’s ability to satisfy What vs how (Step 6)

given in the customer’s requirements. Target information- how much (step 7)- is developed in

the basement of the house. Finally, the interrelationship between the engineering specifications

are noted in the attic of the house- How versus how (Step 8)

In the product development step, the QFD provides the various solutions with engineering

specifications for various problems that researchers have. It gives a complete structure for the

development and allows us to know the more specific requirements. The solutions developed

from the QFD is made used for concept generation. [1]

2.3. CES EduPack

This is a unique set of teaching resources that support materials education across

engineering, Design, Science, and sustainable development. CES EduPack is the world’s

leading teaching resource for materials. It has been exclusively developed by granta design in

collaboration with professor Ashby and growing community of educators of 1000 universities

and colleges around the world. Material selection is a step in the process of designing any

physical object. In the context of product design, the main goal of material selection is to

minimize cost while meeting product performance goals. Systematic selection of the best

material for a given application begins with properties of the candidate materials. The enhanced

eco audit tool is used for higher level of teaching and research which comes with the CES

EduPack eco design edition, adds consideration of the following process options. It is also

possible to calculate cost for the different life cycle phases, helping students to think about both

environmental and economic factors. The Eco design editor comes with extended property data

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for over 3750 materials. This allows CES EduPack’s powerful selection and analysis software

to be used in projects to investigate and compare the environmental impact of materials and

processes. The enhanced eco audit tool can be used as part of a 2-step process in which the

student first analyses a product to identify the key drivers of its environmental impact and then

move on to make materials selections that impact. [2] So, we are selecting a material by using

CES EduPack software, which can be observed from the graphs present in the Appendix.

2.4. Preparation and Data collection:

We have taken guidance for completion of the thesis from our Industrial Supervisor Mr. Michel

Bano and our University Supervisor Mr. Lars Bååth. This project required the complete

understanding of the various concepts of the automobile design. Our Industrial supervisor

provided the design requirements and criteria upon which the final CAD design was generated

using the CAD software CATIA V5R19. Later the generated design was analyzed for structural

stability using the ANSYS 15.0 software. Followed by construction of the proto type by using

the 3D printing technology.

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CHAPTER 3: THEORY

3.1 Chassis Types

1. Ladder Frames

The ladder frame is one of the simplest and oldest of all designs. It consists of two symmetrical

beams, rails, or channels running the length of the vehicle. The ladder frame is called so because

it resembles a ladder with two side rails and several cross beams. The ladder frame chassis is

constructed with cross beams of channel sections as well as side frames; this because of the

torsional stiffness to the whole structure is very low. [4]

Figure: 3.1.1 Ladder Frame [11]

The torsion in the cross members is reacted as bending in the side frames, and the bending in

the cross members, reacted as torsion in the side frames. It is also observed that all the members

are loaded in torsion and due to their low torsional constants. This frame has low torsional

stiffness. The important point is to notice that if the open sections are replaced by closed

sections, then the torsional stiffness is greatly increased. This can be observed in the vehicles

such as Land Rover. The greatest advantage of the ladder frame is its adaptability to

accommodate various vehicle body shapes. It is particularly used for light commercial vehicles.

It is still widely used for box vans and tankers to detachable containers. [3]

2. Backbone tube Chassis:

The back-bone tube design is very commonly found in sports cars. It consists of a strong tubular

back bone which is usually rectangular in cross section that connects the front and rear

suspension attachments of the vehicle. This design was first developed in 1923 by Hans

Ledwinka who was the chief designed at Tatra heavy trucks.

He further enhanced this design with 6*4 model Tatra 26, which had great off road abilities.

Some of the vehicles which are using this chassis design are Europa, Lotus E spirit and Skoda,

etc. Some cars also make use of the backbone part of the chassis to strengthen is such as

Volkswagen Beetle. Thus, the concept of hybrid backbone ladder chassis developed. On this

regard the Locost was developed by using this concept of a backbone in addition to the outer

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space frame. [5]

Figure: 3.1.2 Backbone tube chassis [7]

Some of the notable merits of this chassis design are as follows:

It has a standard super structure that can withstand torsion twist and subsequent

wear that can reduce the vehicle’s lifespan.

The half axles will have better contact with ground when they are operated off-

road, when compared if they are operated on roads.

A thick tube covers the most vulnerable parts of the drive shaft so that the whole

system would be highly reliable. Even here the problems related to their repairs

might occur which could be complicated.

The modular system which exists in this design enables a configuration 2-,3-,4-

,5-,6- or 8-axle vehicle with different wheel bases.

Some of the notable demerits are as follows:

The manufacturing process of the back-bone chassis is very complicated and

extremely cost in-effective, unless more axles with all wheel drives are included

that could be more cost effective for this design.

Adding to this demerit that backbone chassis is having for a given torsional

stiffness when with compared Uni-body.

This design has a major drawback when it comes to the aspect of safety as the

chassis gives no protection against side impacts such as collisions.

10

3. X- Frame or Cruciform Frame:

General Motors used the X-Frame design, during the late 1950’s and early 1960’s. In which the

rails from alongside the engine seamed to cross the passenger compartment, each containing to

the opposite end of the cross beam at the extreme rear of a vehicle.

Figure: 3.1.3 X- Frame or Cruciform Frame [3]

This design was particularly chosen to decrease the overall weight of the vehicle regardless of

the increment in the size of the transmission and propeller shafts humps, since can row had

taken cover the frame rails. It is also observed that several models have differential located not

by the customary bar between axle and frame but by a ball joint atop the differential connected

to a socket in a wishbone hinged on to a cross-member of the frame. The major drawback of

this design is that it lacks side rails thus it fails to provide adequate side impact and collision

protection. Thus, this design also fails on the aspect of design safety. Thus, the perimeter frame

has replaced this X-frame. [3]

4. Perimeter Frame:

The perimeter frame tries to overcome the drawbacks of the x-frame design. It is mainly used

in motorcycles, having different shapes and sizes. The reason for this is most motorcycles have

a warped version of this tubular frame design. The main aim of this design is to create the

shortest path between the most stressed parts of the motorcycle, for maximum stiffness and

stability. In his design the front forks are mounted at the left most end and the rear swing arm

is attached to the right most. The engine is placed in the empty space between them. The

perimeter frame can be seen to be used in Bajaj Pulsar 200 Ns motorbike. The engine is

suspended in the middle with the wire frame around it. The cylinder head also exerts stress on

the frame thus increasing and maximizing the stiffness of the frame, as the weight of the

perimeter frame is low. It helps in mass centralization hence improving the handling

characteristics of a vehicle. [15]

11

Figure: 3.1.4 Perimeter Frame [6]

5. Space Frame:

It is also known as 3-Dimentional chassis frame. It is called so because unlike other chassis

types which are essentially 2-dimensional having only length and breadth in this design the 3rd

dimension has been considered. By considering the depth of the frame 3-D Frames have

managed to increase the bending strength and stiffness of the entire design. [3]

Figure: 3.1.5 Space Frame [9]

These types of frames have been mainly used for specialist cars such as sports racing cars. Some

of the notable examples for space frame cars include Audi R8, Ferrari 360, Lamborghini

Gallardo, Mercedes-Benz SLS AMD and Pontaic Fiero.

This type of vehicle design can be mainly used for low volume production. One important

aspect of this vehicle structure is that all the planes of the frame should be fully triangulated, so

that all elements are essentially loaded in tension or compression. The main drawback of this

design is that it encloses much of the working volume of the car and it can make access for both

the driver and the engine difficulty, therefore the Space frames have been designed with

removable section joined by pin-joints. Such a structure can be seen around the engine of the

Lotus Mark III. Although the space frame design is considered somewhat inconvenient for its

12

passengers, the, main advantage of this design is the lack of bending forces in the tubes that

allow it to be modelled as a pin jointed structure meaning that the removable sections need not

be designed to reduce the strength of the assembled frame. [3]

6. Uni-body Frame:

It is also known as the monocoque structure. In this design the vehicle frame and body are

integrated into one single strong structure. This integral frame and body construction requires

more than just welding an unstressed body as see in conventional frames. It is a fully integrated

body structure where the entire car is a load caring unit that handles all the loads experienced

by the vehicle i.e. the forces acting on the vehicle during motion, as well as the cargo loads.

These types of integral bodies for wheeled vehicles are manufactured by forming or casting

whole sections as one piece or by welding metal panels and other components together by

forming or by a combination of all these techniques. This is because the car outer skin and

panels are made as load bearing having ribs, bull heads and box sections to reinforce the entire

body. From the 1990’s onwards the safety regulations for chassis designs became stricter thus

more rigid chassis were developed. The traditional steel monocoque which was being used at

that time became increasingly heavy. This made vehicle designers to turn towards alternative

materials to replace steel, which lead to the introduction of aluminum as an alternative. There

has been no mass production of any other car other than Audi A8 and A2 which could complete

eliminate steel in the chassis construction. From this time, onwards increasingly cars started

using aluminum in their body panels such has bonnet, boot lid, suspension arms and mounting

sub-frames. [3]

Figure: 3.1.6 Uni-body Frame [10]

The manufacturing technique, conventionally used for Uni-body construction was pressing. But

this technique had a major drawback, pressing used heavy-weight machines to press sheet

metals in to die, this created in homogeneous thickness, which made the edges and corners

always thinner than surfaces. To maintain a minimum thickness, the car designers had to choose

thicker sheet metals than the originally needed. These situations lead to the Hydro-form

technique to be introduced.

In this technique, instead of using sheet metal, it forms thin steel tubes. And these steel tubes

are placed in a die that can define the desired shape when a fluid of high pressure is pumped in

13

the tubes expanding the latter to the inner surfaces of the die. As the pressure of the fluid

involved is non-uniform, the thickness of the steel made is also non-uniform. Thus, the

designers using this technique manage to minimize the steel thickness and reduce the weight of

the structure. [3]

7. Sub Frame:

The main advantage of this chassis is that it is stronger and lighter than the conventional

monocoque design without increase of production cost. And the main drawback of this chassis

is that it is still not strong or light enough for the sports cars. [13]

Figure: 3.1.7 Sub-Frame [8]

These sub frames are commonly found at the front or rear end of vehicles and are used to

attach the suspension to the vehicles. It may also contain the engine and transmission and it’s

normally a tubular or box sheet construction. Some of the examples of passenger cars using

such a construction are the 1967- 81 GMF Platform and the GMX Platform 1962. [13]

3.2 Types of Stresses acting on the Chassis:

After studying about the various loads acting on the vehicle the following types of stresses can be identified, such as

1. Allowable Stress:

It is important to understand the worst load conditions that the stresses induced into the structure of the vehicle to keep these stresses within acceptable limits.

By considering all the static load factors acting on a road going passenger car the stress level should be below the yield stress.

Example, In the case of a road going passenger car its bending case is having the maximum allowable stress which should be limited as follows.

Stress due to static load * Dynamic Factor ≤ 2/3 *Yield Stress

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From the above equation, we can understand that the worst dynamic load condition acting on

the vehicle structure should not exceed more than 67% of the yield stress. In addition, the safely

factor against yield is 1.5 for the worst possible load conditions on the vehicle structure.

Therefore, the above procedure is usually suitable for designing against fatigue failures, but the

fatigue investigation at the points where the stress concentration occurs such as the suspension

mounting points. [3]

2. Bending Stiffness:

From the previous sections of loads and stresses which we have considered thus we can now

determine whether a passenger car structure is sufficiently strong most designers are

considering stiffness is more important that strength. Therefore, designing for acceptable

stiffness is more critical than designing for sufficient strength.

The bending stiffness in the case of passenger cars can be determined by the acceptable limits

of deflection of the side door. In the case of excessive deflection, the door of the passenger cars

will not shut satisfactorily due to the misalignment of the door latches resulting in a situation

where the doors cannot be opened or shut easily.

Any deflection of the floor under the passenger’s feet is a case of concern as it results in

passenger insecurity. Therefore, the load stiffness of the floor is important for passenger

acceptance. To reduce the panel vibrations of the floor, these floor panels are stiffened by

swages pressed into the panels to reduce the deflections, and panel vibrations. Currently modern

passenger cars use sandwich material having 2 thin panels separated by a honey comb material

which leads to a much lesser deflection and vibration of the vehicle. [3]

3. Torsional Stiffness:

It is found that the acceptable torsional stiffness can be evaluated for only specific criteria, but

for other criteria this usually based on the previous experience. From this previously gained

experienced for a typical medium sized sedan which is fully assembled will have a torsional

stiffness of 8000 to 10000 N-m/Degree. And this condition is applicable when measured over

the wheel base of the vehicle. We can also note that from previous experience this would be

applicable for road going passenger cars. In this case where torsional stiffness is low the driver

of the car would have a perception that the front of the vehicle appears to shake.

In generally when a vehicle is parked on an uneven ground such that one wheel is on a kerb or

in the corners of the vehicle for wheel change the same problem of difficulty to close the vehicle

door would occur from the studies of Webb (1984) the torsional stiffness is can also be

influenced by wind screen and the backlight glass. Per his studies the glass removal reduces the

torsional stiffness of the vehicle by approximately 40%.

From Webb’s study, we can conclude that the glass is subjected to a load and hence a stress. If

the load and stress are increased excessively could lead cracking of glass. From this research, it

was found that cars with no structural roof panels are likely to have poor torsional stiffness

unless the under body of the cars are reinforced. From all these observations [3], we understand

that low torsional stiffness can have a detrimental effect on the vehicle handling characteristics.

15

3.3 Material Selection

During the process of material selection, the choice of the material for a vehicle is the most

important factor for automobile design. There exist numerous types of materials which can be

used for the automotive body and chassis construction but it is also important that they meet

certain requirements such as light weight, economic effectiveness, safety, recyclability, and life

cycle considerations. The above criteria are the result of legislations and regulations and some

are also the requirements of customers. Among these criteria there may be contradictions.

Therefore, the optimization is important over of the structures or components under

consideration. It also requires the knowledge of [12] [14]:

Operating or service environment, for example temperature, humidity conditions,

presence of chemicals, and so on.

Manufacturing processes that can be used to produce the structure or the component.

Cost, it includes not only material cost but also the cost of transforming the selected

material to a final product.

Safety

Recycling

Types of loading for example: Bending, Axial, torsion or combination

Modes of loading for example fatigue, static, impact, shock and so on.

Service Life

3.3.1 Materials used for chassis manufacturing:

1. Steel

When it comes to chassis construction, steel is the first choice. From past few decades, the

performance characteristics of steel such as strength and stiffness have improved. There have

been many developments in iron and steel manufacturing therefore increasingly light weight

steel is not only used to manufacture engines and wheels of vehicle bodies but also chassis. Iron

and steel form a critical element for the structure of majority of vehicles as they are of lower

cost. The primary reason for using steel in the body structure is its inherent capability to absorb

impact energy in crush situations. [12] [14] 2. Aluminum Aluminum has the potential to reduce the weight of the vehicle body as it has a low density and

high specific energy absorption performance. It also exhibits good corrosion resistance and a

good specific strength. The aluminum usage in automotive industry has increased over the past

decades. For chassis applications, the aluminum castings are used for about 40% of wheels and

brackets. The recent developments have shown that up to 50% weight saving for the body

16

weight by substituting steel by aluminum. Pure Al bodies have been developed and

implemented for mainly luxury cars such as Audi A8 and BMW 28, because of their

comparatively high material and production cost. [12] [14] 3. Magnesium It is another light weight metal that is becoming increasingly common in automotive

engineering. It is 33% lighter than Al. And 75% lighter than steel/ cast iron components.

Although the tensile strength of magnesium is same as Al, it has a lower ultimate tensile

strength, fatigue strength when compared to Al. And the thermal expansion co-efficient is

higher for Magnesium. It has better machinability, manufacturability, longer die life and faster

solidification. [12] [14]

3.3.2 Advanced materials

1. Plastic composites

It is one of the newest materials being used for vehicle frame design they are currently used for

formula-1 racing car chassis. The plastic composites have managed to make inroads into the

chassis market as they have an advantage of light weight and shock absorption ability. The

world’s second all plastic vehicle the ‘Baja’ has a plastic composite chassis. This vehicle is

ideal for off-road tropical environments. It has the composite body and chassis which can resist

sand and sea water, its combined thermos-plastic and thermoset skin and frame, take advantage

of plastic’s strength to manage energy thus enabling it to pass both the US and European crash

tests. The most important advantage of this material is its weight savings and making them

easier to transport, providing consumers with better fuel economy. [12] [14]

2. Fiber Reinforced Composites It is popular due to its benefits that have a potential for weight saving offered by low density.

As the weight reduction, could lead to lower fuel consumption, resulting in wider economic and

environmental impacts. They have excellent resistance to corrosion and other chemical

environments which could help manufacturer to pro-long the life time of individual components

of vehicles. It is mainly used in automobile industry for the manufacture of body components,

engine, chassis, etc. Fiber reinforced composites materials consist of fibers of high strength and

modulus embedded in or bonded to a matrix with distinct interfaces between them. [12] [14] 3. Carbon Fiber Epoxy Composites In recent times, racing car companies rely on the composites, it would be in the form of plastic

composites such as Kevlar and most importantly carbon fiber epoxy composites. It is because

the composite structures have high strength or low weight ratio, which particularly benefits the

racing car structures. The basic chassis of the formula one racing car is a monocoque

construction which has 3 layers. It is used to construct the outer skin by building several layers

of Carbon fiber reinforced epoxy in a mould. Furthermore, the flexibility of this process

authorizes new design ideas which are not possible by using metal construction. [12] [14]

17

4. Glass Fiber Composites It is currently being used in sports cars such as formula one. And is lighter than steel and Al, it

is easy to shape and is rust proof. Furthermore, importantly it is inexpensive when produced in

smaller quantity. Currently, Lotus, TVR, GM’s Camaro, Venturi, etc., have used glass fiber in

the non-stressed upper body that helps to get tolerance between the connecting points resulting

in improved aerodynamic efficiency and more attractive enclosures. [12] [14]

18

CHAPTER 4: RESULTS Product development is carried out in various ways and the best ways that are in practice for

this process is through generating the house of quality also known as the Quality Function

Deployment (QFD). This main importance of this stage is that it enables us to generate the

engineering specifications after listing the customer requirements also called Voice of the

customer (VOC). The data required for generating the QFD can be collected by below steps:

1. Hearing the Voice of the customer (VOC) 2. Developing the specification or goals for the product. 3. Finding out the specifications measure the customer’s desires. 4. Determining how well the competition meets the goals. 5. Developing numerical targets to work toward. [1]0

4.1 House of Quality for Types of chassis Selection

Understanding the design problem is an essential foundation for designing a quality product.

To translate customers’ requirements into technical specifications of what needs to be

developed. In this project, the best suitable type of Chassis for the Uniti electric vehicle is

proposed. And this task of selection for the best type of chassis is well accomplished by building

a QFD.

1.Identify the customers- who they are: We identified our customers based on the type of chassis

they prefer. Therefore, we have identified ‘manufactures’ and ‘agents’ as our customers.

2.Determine the customers’ requirements-what do the customers want: Customers require

comfort and safety; they are categorized in different areas as we can see in the table below.

3.Determine relative importance of the requirements- ‘who versus what’: The important of

each requirement is evaluated by given more weight to most important ones and less weight to

less important ones. All the needs are not equally important to all customers. As we can see the

above table that different priority for each step like 1,2 to 5 so on.

4.Identify and evaluate the competition how satisfied are the customers now: It is a competition

block where we can easily find the best one among the various types of chassis. In this we will

give 1 to 5 rating to find the best chassis type and we will compare as we can observe in the

table the Space frame-III has good ratings. This block is very important to identify the best

Chassis type, as when we compare with all other remaining chassis types like Ladder frame, X-

frame etc.

5.Generate engineering specifications how will the customers’ requirements be met: The goal

here is to develop a set of engineering specifications from the customers’ requirements. The

specifications are the restatements of the design problem in terms of parameters that can be

measured and have target values. These specifications are a translation of the voice of the

customers into the voice of the engineers.

19

6.Releate customers’ requirements to engineering specifications- how to measure what: This

block is in the center position of house, and it tells about the engineering specification that

relates to the customer needs and the strength between their relationships for every combination

of these relationships are conveyed through ratings like 1,2,3, to 9

9-----------------Strong relationship

3-----------------Medium relationship

1-----------------Weak relationship

0------------------No relation at all

7.Set engineering specification targets and importance- how much is good enough: The first

goal in this step is determining the importance for each specification by simple calculations.

The following steps are followed for calculating the priorities. For each customer, multiply the

importance weighting from step 3 with the 0-1-3-9 relationship values from step 6 to get the

weighted values. Normalizing these sums across all specifications. One sum across all

specifications is 951. So, first technical specification priority for designer is 255/951 = 26.81%.

Same procedure for all remaining specifications and finally we got cost for higher priority is

26.81% and less priority is 2.83% is changeable position of chassis.

8. Identify relationships between engineering specification- how are the ‘hows’ dependent on

each other: Each engineering specification is someway dependent on any other specifications.

This shows that working on a specification gives a positive or negative effect on the dependent

specification. In the table, below this relationship is shown by using symbols. [1]

20

Table:4.1.1: House of Quality: (QFD for Type of Chassis Selection) [1]

21

4.1.2 Pro- Con Analysis for the types of chassis:

1. Ladder Frame:

Pros Cons

1. The torsional stiffness of the whole 1. It is mainly used only on trucks structure is very low. and heavy duty vehicles and thus

2. It is the simplest among all the not popular for normal passenger

different chassis designs. cars.

3. The greatest advantage of the ladder 2. It is a 2-dimensional structure

frame is its adaptability to having a torsional rigidity much

accommodate various body shapes. lower than another chassis

4. It is cost effective and especially when dealing with

can even be hand built. vertical loads or bumps. [4][3]

2. Back bone Tube Chassis:

Pros Cons

1. It is most commonly used in sports 1. It has a very complex manufacturing Cars process, Thus its cost ineffective for

2. It has great off road abilities mass production

3. This chassis design is highly reliable 2. On the aspect of safety this type of

4. The most space saving among other chassis does not provide any

monocoque chassis is the backbone protection against the side impacts

tube chassis. such as collisions [5]

3. X-Frame or Cruciform Frame:

Pros Cons

This chassis design is suitable is often chosen This design also fails on the aspect of design to decrease the overall weight of the Safety. [3]

vehicle

22

4. Perimeter Frame:

Pros Cons

1. The perimeter frame tries to 1. It is mainly used only for motor- overcome all the draw backs of the X- cycles thus it is not suitable for use in

Frame 4-wheel passenger cars. [15]

2. It creates the shortest path between

the most stressed parts of the motor

cycle for maximum stiffness and

stability.

3. It helps in mass centralization and for

improving handling characteristics of

the vehicle.

5. Space frame:

Pros Cons

1. It is a 3-Dimensional chassis frame 1. This type of design is used mainly for which has managed to increase the low volume production of specialist

bending strength and stiffness of the cars such as sports cars.

entire design. 2. A drawback of the space frame

2. It has a lack of bending force in chassis is that it encloses much of the

the tubes allowing them to be modeled working volume of the car and can

as a pin-jointed structure. This does not make access for the engine and

mean that the presence of such a the drive difficult. [3] removable section could affect

the strength of the assembled

frame.

3. The advantage of using tubes rather

than the previous open channel

section is because they resist torsional

forces better.

23

6. Uni-body Frame:

Pros Cons

1. This chassis design is stronger and 1. It is not suitable for use in sports cars lighter than the conventional this is main draw back.

monocoque design without increase 2. For manufacturing this frame, pressing

of production cost. technology is used which is a major

2. This design provides weight savings, drawback as pressing uses heavy

improved space utilization. weight machines to press sheet

metals. [3]

7. Sub-Frames:

Pros Cons

1. The sub-frame is attached to a Uni- 1. The sub-frames are prone to body frame so that it can handle high misalignment which can cause

chassis forces. vibration and alignment issues in the

suspension components.

2. Sub frames are used to provide 2. A miss-alignment may be caused by a accurate road wheel control while space between chassis-sub frame

using a swift light weight body. [13] monitoring bolt and monitoring hole.

After evaluating all the different aspects of the various chassis, we have managed to short list

some important aspects on the different chassis types so that we could select the best type of

chassis design for our project.

4.2 House of Quality for Material Selection:

Understanding the design problem is an essential foundation for designing a quality product. To

translate customers’ requirements into technical specifications of what needs to be developed. In

this project, the best suitable type of material for manufacture of the Uniti electric vehicle is

proposed. And this task of selection for the best type of chassis is well accomplished by building

a QFD.

1.Identify the customers who are they: we identified our customers who purchase material to build

the chassis. Therefore, we have identified the manufactures and agents as our customers.

2.Determine the customers required what do the customers want: customers require mainly

comfort and safety, they are categorized in different areas as we can observe in the table below.

3.Determine relative importance of the requirements who versus what: the importance of each

requirement is evaluated by giving more weight to most important ones and less weight to less

important ones. All the needs are not equally important to all customers. As we can see the above

table that different priority for every step like 1,2 to 5 so on.

24

4.Identify and evaluate the competition how satisfied are the customers now: it is a competition

block where we can easily find the best one among the bunch of materials. In this we will give 1

to 5 rating to find the best material and we will compare as we can observe in the table. Carbon

fiber-IV has good ratings. This block is very important to identify the best material, as when we

compare with all other remaining types of materials like steel, aluminum etc.

5.Generate engineering specifications how will the customers’ requirements be met: the goal here

is to develop a set of engineering specifications from the customer’s requirement. The

specifications are the restatement of the design problem in terms of parameters that can be

measured and have target values. These specifications are a translation of the voice of the

customers into the voice of the engineering.

6.Releate customers’ requirements to engineering specifications how to measure what: this block

is the center position of the body and it tells about the engineering specification that relates to the

customer needs and the strength between their relationships for every combination of these

relationships are conveyed through ratings like 1,2,3, to 9

9-----------------Strong relationship

3-----------------Medium relationship

1-----------------Weak relationship

0------------------No relation at all

7.Set engineering specification targets and importance how much is good enough: the first goal

in this step is determining the importance for each specification by simple calculations. The

following steps are followed for calculating the priorities. For each customer, multiply the

importance weighting from step 3 with the 0-1-3-9 relationship values from step 6 to get the

weighted values. Normalizing these sums across all specifications. One sum across all

specifications is 1191. So, first technical specification priority for designer is 126/1191 = 10.57%.

Same procedure for all remaining specifications and finally we got cost for higher priority is

28.71% and less priority is 6.04 % is easy to get (availability).

8. Identify relationships between engineering specification: how are the hows dependent on each

other: Each engineerin g specification is someway dependent on any other specifications. This

shows that working on a specification gives a positive or negative effect on the dependent

specification. In the table, above we had shown the relationship by using symbols. [1]

25

Table: 4.2.1: House of Quality: (QFD for Material Selection) [1]

26

4.2.1 Pro Con Analysis for material selection:

Material: Steel

Pros Cons

1. They have been used from many 1. Steel is susceptible to corrosion. decades for the construction of 2. It low fire resistance.

engines, wheels, and chassis as 3. Buckling and high deformation

they are stronger, stiffer and due to small sizes of members.

have improved performance.

2. Steel can be recycled in

without losing their

quality and due to its magnetic

properties steel is particularly

easy to recover unsorted wastes.

3. Steel has the property of

ductility therefore it is easy to

form shape and weld when

relatively large forces are

applied to it.

4. Steel is the least expensive

material used for manufacture

of automobile chassis and

motorcycle frames. [12] [14]

Material: Aluminum

Pros Cons

1. Aluminum is light in weight as 1. It has poor weldability

it has low density 2. It has poor fatigue resistance

2. By using the Aluminum chassis and young’s modulus

in automobiles, the vehicle fuel 3. It has poor strength unless

efficiency improves. Alloyed

3. Al has excellent thermal

conductivity useful in scenarios

in rapid transmission and exit of

heat especially engines and fins.

[12] [14]

27

Material: Magnesium

Pros Cons

1. Lower assembly cost and 1. Magnesium is highly higher production speed. flammable in its pure form.

2. It improves reliability and 2. It is expensive when

has superior dimensional compared with Al and Steel.

stability. 3. When Mg is exposed to

3. Magnesium leaves lesser white light it emits UV rays,

scrap. [12] [14] which is harmful to the

human eyes.

Material: Plastic Composites:

Pros Cons:

1. Plastic composites have the 1. During corrosion, there exists advantage of being light a chance of failure leading to

weight and easy to transport. safety concerns.

2. They have good shock 2. Plastic materials may not

absorption ability. sustain high temperature for

3. They can resist against long periods of time thus

adverse climatic conditions. leading to failure. [12] [14]

Material: Carbon Fiber

Pros Cons

1. Carbon fiber composites are 1. Carbon fiber is expensive 3.8 times stronger than steel, 2. The recyclability of carbon

4.5 times stronger than fibers are difficult. [12] [14]

Aluminum Alloys, 7.4 times

stronger than titanium.

2. It has excellent strength to

weight ratio when compared

to other materials.

3. It has good production

flexibility as it can easily be

formed into complex shapes.

28

Material: Glass Fiber

Pros Cons

1. They have high temperature 1. They are brittle Resistance 2. They have weak abrasive

2. They are inexpensive resistance. [12] [14]

3. They are non-flammable

4. They improve the

aerodynamic efficiency

From the above Pro-Con analysis and QFD, we understood the prerequisites of an ideal or

suitable chassis for uniti L7e vehicle such as, what chassis structure best suits the vehicle kind

, and ideal/sustainable material to manufacture the same. By comparing all the materials in the

QFD, Carbon fiber-IV got a more rating of 5 as we observe in table 4.2.1 So the result from

the QFD is carbon fiber-IV, when we follow all eight sequential steps of QFD with the

Technical engineering specifications,safety,comfort and others.

From the Pro-Con Analysis by compairing all the materials as of carbon fiber composites are

3.8 times stronger than steel, 4.5 times stronger than aluminum alloys, 7.4 times stronger than

Titanium. It has exellent strength to weight ratio when compaired to other materials. It has

good production flexibility as it can easliy be formed into complex shapes and even as of our

requirment is to select a sustainable material which suits the uniti car.

The same procedure is followed for selecting the sutaible chassis for the Uniti L7e CP vehicle.

By comparing all the different frames in the QFD the Space frame-III got more rating of 5.

Therefore the result from the QFD is Space Frame-III. When we follow all the 8 principle of

QFD with the Egineering technical specifications, Safety, Comfort, and Others as we observe

in table 4.1.1. From the Pro-Con Analysis, Space frame has weighed pros than cons when

compaired with all different types of chassis, as it is a 3 dimensional chassis frame which has

managed to increase the bending strength and stiffness of the entire design. It has a lack of

bending force in its tubes allowing them to be modeled as a pin-jointed structure. This does not

mean that the presence of such a removable section could affect the strength of the assembled

frame. The advantage of using tubes rather than the previous open channel section is because

they resist torsional forces better.

From all these observations, we have gathered enough information for making the correct

selection of the Chassis design and material for its manufacture as Space frame and Carbon

fiber composite material respectivelly.

29

4.3 Design of Chassis The design of chassis for the Uniti car is the objective of our Project. This design requires the use of various CAD and Simulation softwares such as CATIA V5 R19 and ANSYS 15.0. The design drawing is shown in various views for better understanding of the design. The chassis of Uniti is with unique measurements and as per the requirements of the L7e category of vehicles. We have therefore designed the Uniti car chassis with exact measurements such as wheel base, track width, and other vehicle measurements. All this became possible by the constant supervision of our industrial supervisor Mr. Michel Bano. Some of the design inputs are listed below:

S. No. Parameter Dimensions in mm

1. Track Width (Front) 1147

2. Track width (Back) 1220

3. Overall Weight (without tyres) 1303.52

4. Overall length (with tyres) 2751

5. Overall width 1226.59

6. Distance from back to back wheel axle 365

7.

Distance from front to front wheel axle 135

8. Tube thickness 20

Table:4.3.1 Design parameters

Our objective is to design a stable chassis which meets all these parameters accurately. To

design the chassis, we are using the CAD (Computer Aided Design) software- CATIA V5 R19.

It can quickly iterate on design ideas with sculpting tools to empower form and modeling tools

to create finishing features, test, fit, perform motion simulations, create assemblies, make

photo-elastic rendering and animations. As per the above-mentioned design requirements, we

have successfully designed the electric car chassis as follows:

30

Fig 4.3.2 Wire frame model of the chassis

By inputting 20 mm as the thickness for the tubular structure of the chassis, we obtain the

following:

Fig.4.3.3 Side view and top view of the tubular chassis structure

31

Fig. 4.3.4 Other different views of the tubular chassis structure

Final Chassis Design:

Fig. 4.3.5 Final tubular design of the chassis structure

32

4.4 Analysis of Chassis:

If you have ever seen a rocket launch, flown on an aero-plane, driven a car, used a computer,

touched a mobile device, crossed a bridge, or used wear technology, chances are that you have

used a product where the design Analysis software ANSYS has played a critical role in its

creation. ANSYS is a global leader in engineering simulation. It helps the world’s most

innovative companies deliver radically better products to their customers. By offering the best

and boldest portfolio of engineering simulation software’s ANSYS helps them solve the most

complex design challenges and engineer projects limited only by imagination.

Founded in 1970 ANSYS employs nearly 3000 professionals, ANSYS technology helps drive

dramatic improvements across their customer’s product development processes, from reduced

cost and shorter development times to improve quality and reliability. The ANSYS Structural

mechanism software brings together the largest elements library with the most advanced

structural simulation capabilities available. This unified engineering environment helps to

streamline processes to optimize product reliability, safety, and functionality, leveraging user-

friendly tools in industry standard products. It improves durability and decreases failure in

automobiles and airplane components. It helps reduce weight while maintaining integrity of air

and space-crafts; test reliability before failure in fields in which failure is not an option [16].

The CAD model of the Uniti Chassis frame, is imported into this software from CATIAV5 R19

where various inputs are provided to start the analysis process of this design. Firstly, the CAD

model is meshed followed by the fixing of fixed supports. Secondly, different loads are applied

and the structural analysis is carried out to obtain the deformation distribution results. All the

results of this analysis are listed in the ANSYS 15.0 structural analysis report in APENDIX.

Fig. 4.4.1 Chassis structure after importing into ANSYS 15.0 and applying material with

meshing generation on the structure.

33

Fig. 4.4.2 Applying of fixed support B (indicated by blue color)

Fig.4.4.3 Applying Forces A, C, D, E, F and H of 166.66 N each on the chassis structure

along with fixed support B

34

4.5 Static Structural Analysis

For a static chassis, a frontal impact force of 1000 N is applied. After applying this resultant

force of 1000 N we can observe the following chassis deformation.

Fig. 4.5.1 Deformation simulation of the chassis structural frame

Fig 4.5.2 Deformation distribution as observed in the chassis deformation simulation

After application of the various forces (A, C, D, E, F and H) of 166.66 N and therefore, a

resultant force of 1000N on the front of the chassis frame structure with fixed support B we

obtain the above deformation distribution showing us the effect of the frontal force’s impact

on the chassis frame and these results confirm us the static structural stability of our chassis

frame structure.

35

CHAPTER 5: CONCLUSION

An ideal chassis for the Uniti EV was designed and constructed using different Product

development methodologies and CAD & analysis softwares, as described and executed in the

thesis. The conclusion from these methodologies were used as inputs to design a suitable type

of chassis for Uniti EV.

The literature study was carried out for better understanding of the whole process of developing

a chassis. Various topics that are researched are listed below:

Types of chassis

Various loading conditions and types of Stresses acting on the Chassis

Materials used for chassis manufacturing

Advanced materials

Material Selection phenomenon

Selected Space Frame Chassis:

From the Pro- Con Analysis for chassis frames, Space frame has weighed pros over cons when

compared with different types of chassis, as it is a 3 dimensional chassis frame which has

managed to increase the bending strength and stiffness of the entire design. Thus we select

‘Space Frame chassis’ as the suitable chassis design.

From Quality Function Deployment (QFD) all the user expectations were listed, technical

specifications were prioritized and all those interdependent technical specifications were also

crossed checked. By comparing all the different frames in the QFD the Space frame got more

rating of 5 (table 4.1.1). Therefore the result from the QFD is Space Frame

Selected Carbon Fiber Composite Material for chassis:

From the Pro-Con Analysis for materials by compairing all the materials as of carbon fiber

composites are 3.8 times stronger than steel, 4.5 times stronger than aluminum alloys, 7.4 times

stronger than Titanium. It has exellent strength to weight ratio when compaired to other

materials. And it has good production flexibility as it can easliy be formed into complex shapes.

Along with this our design requirment and criteria was to select a sustainable material which

could suits the uniti EV. Thus, we select ‘Carbon fiber’ composite material for the manufacture

of the chassis structure. By comparing all the materials in the QFD Carbon fiber also got the

most rating of 5 table (table 4.2.1). So the result from the QFD is carbon fiber.

The dimensional specifications of Uniti EV helps us to design an accurate chassis structure.

The CAD and simulation software which used for drafting, designing, and analyzing are:

CATIA V5R19 and ANSYS 15.0.

Achieved the required chassis design for the Uniti EV, with accurate results for static structural

Analysis from ANSYS 15.0.

36

CHAPTER 6: CRITICAL REVIEW

The master thesis was initiated with the selection of the best type of vehicle chassis

frame and the material which would be most suitable for the manufacture of an L7e category

Electric vehicle. All this became possible only after we completed a comprehensive literature

study about the various types of chassis frames which are being used currently in the market

and the different types of materials used for their manufacture. By making use of the Pro- Con

analysis we could list the different merits and demerits of using the various types of chassis

frame designs and different material types.

With the generation of the House of Quality (also called Quality Function Deployment) gave

us various engineering specifications and solution towards choosing the ideal design suitable

for the Uniti EV. The QFD helped to develop technical requirements (or engineering

specifications) which were given numerical logic in the central block of the QFD, as we knew

what values to be given during the actual designing and analysis process of the chassis

structure. The CES EduPack software was made use in order find the best suitable material for

manufacturing the chassis frame. The final design became possible after carefully

implementing all various engineering specifications into the actual design in the CAD

(computer Aided Design) software.

During generation of the QFD a more comprehensive customer feedback market survey could

have given us better engineering specifications. The limited knowledge about the final design’s

dimensions during the design stage made it difficult for us to initiate the design process in the

initial stages. During the analysis stage the compatibility of the CAD file created using the

CAD software (CATIA V5R19) initially created minor issues while importing in to the analysis

software (ANSYS 15.0). The limited number of structural stability simulation tests carried out

might not have provided sufficient information regarding the structural stability of the chassis

frame.

When we started the analysis of our chassis frame design due to the time limitations and

compatibility issues of importing the CAD files from the different CAD software to Analysis

software resulted in us able to carry out only the very important static structural stability

analysis simulation test, which tested the static stability of our chassis frame structure, with

only one frontal load of 1000 N. More test could have provided us with better understanding

about the structural stability of our chassis frame structure.

Environmental and Sustainability concerns:

This project aims to develop the most suitable chassis frame structure for the L7e CP category

electric vehicle being developed by Uniti Sweden AB. At Uniti, our goal is to develop a new

vehicle for modern urban mobility. As we feel the existing automobile industry has failed to

recognize the importance of sustainable development and have befriended the environment.

Therefore, we have selected Carbon fiber as the material for the chassis over many other

materials considering this important aspect. Indeed, that might not be ideal for the environment

as Carbon fiber also has a significant carbon foot print, considering this we are still researching

37

the possibility of opting a hybrid material like Carbon-cellulose fiber composites considering

its better environmental aspect.

Health and Safety:

The health and safety is extremely important for any sustainable development. At Uniti we give

at most importance to this aspect as well. The Carbon fiber composite material used to

manufacture the chassis makes use of a Petroleum based resin material which might not be

biodegradable and could be toxic to the environment, thus could affect the health of the

personnel involved in its manufacturing process. Therefore, this again leads us to find more

sustainable and safe resin materials like bio based green resins which as more safe.

Economy:

When developing a vehicle that aims to change and revolutionize the entire auto industry by

giving extreme importance to sustainability and environmental concerns the cost of the vehicle

gets highly impacted. As we do not want to make cost the prime factor while selecting the

suitable material for manufacture, we have selected carbon fiber and space frame structure over

possible economical options such as plastic composite materials. Although carbon fiber

composites are highly expensive.

Ethical Aspects:

From the start of this project the one aspect that we value the most is this important aspect of

engineering ethics. We consider it as more important for engineering firms to reflect upon this

aspect more than for mere economic gains. We find this culture existing in the firm Uniti

Sweden AB which gives us more pleasure.

Our Master Thesis University supervisor Prof. Mr. Lars Bååth guided us to follow the

correct methodology throughout the entire thesis project. And our Industrial Supervisor, Mr.

Michael Bano helped us to follow the correct approach to carry out the literature study on

materials used for chassis manufacturing and to develop a better understanding about the

relevant current technologies and future materials under research. As of future study on this

regard we would be working for Uniti Sweden AB to develop better chassis frame designs with

numerous iterations so that they suit the new versions of Uniti EV.

38

CHAPTER 7: REFERENCES

1. David G. Ullman (2010) The Mechanical Design Process, Fourth Edition

2. CES EduPack Overview: Granta Design

URL:https://www.grantadesign.com/download/pdf/CES-Edupack-2016-Overview.pdf

3. Julian Happian-Smith (2002) An Introduction to Modern Vehicle Design

4. Mr. Birajdar M. D., Prof. Mulley. (2015) Design Modification of Ladder Chassis Frame

International Journal of Science, Engineering, and Technology Research (IJSETR),

Volume 4, Issue 10, p 3443- 3449

5. Backbone chassis Explained URL http://www.motor-car.co.uk/car-body/item/15086-

backbone-chassis

6. Perimeter Frame URL: http://www.bikes4sale.in/kb/motorcycle-frame.php

7. Backbone tube chassis URL: http://designthedesire.blogspot.se/2015/04/chassis.html

8. Sub-Frame Lamborghini Aventador LP 700-4 chassis

URL: http://www.flickr.com/photos/jsmith831/6099339034/ Lamborghini Aventador

LP 700-4 chassis Date=2011-08-30

9. Julian Happian-Smith (2002), An Introduction to Modern Vehicle Design (p 141)

10. Uni-body Frame URL: http://www.web2carz.com/autos/car-tech/2332/body-on-

frame-vs-unibody-construction

11. Ladder Frame URL: https://carsexplained.wordpress.com/2016/06/12/__trashed/

12. Elaheh Ghassemieh, Materials in Automotive Application State of the Art and Prospects

University of Sheffield UK, (p 373- 383)

13. Mark Wan, Different Types of Chassis Copyright© 1998-2000 by Auto Zine Technical

School URL: http://www.autozine.org/technical_school/chassis/tech_chassis.htm

14. Dr. Hossenein Saidpour (2004), Lightweight High Performance Materials for car body

Structures.

15. Pratik Patole (2015), Motorcycle Perimeter Frame- All You Need To Know URL:

http://www.bikesindia.org/reviews/motorcycle-perimeter-frame-all-you-need-to-

know.html

16. Sudhir Sharma, Director, High Tech Industry Marketing, ANSYS (2016) Excellence in

Engineering Simulation Advantage Special Edition URL:

https://www.google.se/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8

&ved=0ahUKEwi8scbz-

pfRAhWDWywKHfjIDl0QFggnMAI&url=http%3A%2F%2Fresource.ansys.com%2Fsta

ticassets%2FANSYS%2Fstaticassets%2Fresourcelibrary%2Farticle%2FANSYS-

Advantage-Best-of-High-Tech-AA-

2016.pdf&usg=AFQjCNHsADNJPxChDyG4cE8gPNnDhhC6_A&sig2=G-

ti6e3kxNmfogs9UnnGrg

Miscellaneous References:

17. R. K. Rajput (2001) A Text Book of Automobile Engineering

18. Automobile Chassis and Frame

URL:http://engineeringpsycho.blogspot.se/2016/02/automobile-chassis-and-

frame.html

19. David A Crolla (2001), Automotive Engineering, Powertrain, Chassis system and

vehicle Body

20. Edwald Schmitt and Elisabeth Lange (2011), Chassis Handbook- Fundamentals,

Driving Dynamics, Components, Mechatronics, Perspectives

39

21. William B. Riley and Albert R. George, Cornell University (2001) Design, Analysis,

and Testing of a Formula SAE car Chassis.

22. Prof. Dipl.-Ing. Johnsen Reimpell, Dipl.-Ing. Helmut Stoll, Prof. Dr. -Jurgen W. Betzler

(2002), The Automotive Chassis Principles Second Edition

23. Sri N.R. Hema Kumar, A Text book on Automotive Chassis and Body Engineering.

40

CHAPTER 8: APPENDIX

Different types of Load conditions on chassis:

Momentary loads acting on chassis - while taking a turn on a curved road

Impact load on chassis- due to collision of vehicles.

Inertia load – while applying brakes

Static load- loads due to chassis part

Over loads- loads applied beyond the design conditions

1. Bending case:

In this case, loading is in a vertical plane, i.e. the x-z plane, which is due to the weight of the

components distributed along the vehicle frame which causes bending about the y-axis. It

depends upon the weights of the major components of the vehicle and the payloads. The first

consideration is the static condition by determining the load distribution along the vehicle. The

axle reaction loads are obtained by resolving forces and taking moments from the weights and

position of the components. [3]

2. Torsion case:

The vehicle body is subjected to a moment at the axle center lines by applying upward and

downward loads at each axle in this case. As the vertical loads always exists due to gravity,

and the condition of pure torsion cannot exist on its own.

The torsion moment eq. can be given as

(Rf /2)tf = (RR /2) tr

Where, tf and tr respectively may be slightly different and the rear axle load RR is usually

smaller than RF for most modern passenger cars (even if they are fully loaded) In these

situations RR is the load on the rear axle for the fully loaded cases and are RF will be less than

the front axle load. These loads are all based on static reaction loads but dynamic factors in this

case are 1.3 and for road vehicles per the Pawlowski for trucks which often go off road 1.5 and

for cross-country vehicles a factor of 1.8 may be used. [3]

3. Combined Bending and torsion:

As torsion, cannot exist without bending as gravitational forces are always present. Theses 2

cases should be considered together when representing a real situation.

In this condition, all the loads of the axle are applied to one wheel. [3]

41

If the left front wheel had been lifted instead of the right rear wheel the same situation would

have occurred.ie, the left rear wheel load will reduce to zero before the right front wheel. Any

further lifting of the left front wheel (or right rear wheel) will not increase the torque applied

to the vehicle structure. [3]

4. Lateral loading:

It happens when a vehicle is driven around a corner or when the vehicle slides against a

sidewalk or pavement i.e. the load acting on the y-axis.

Let us consider the case of cornering, in this situation lateral loads are generated at the tyre to

ground contact patches. Centrifugal forces balance theses patches i.e., MV2/R [3]

42

Let us consider the situation when the wheel reaction on the inside of the turn drops to zero,

i.e. when the vehicle rolls over. This condition the vehicle structure is subjected to bending in

the x-y plane. This condition also depends upon the height of the vehicle center of gravity and

track. At this condition the resultant of the centrifugal force and the weight passes through the

outside wheels contact patch. [3]

MV2

𝑅(h)=Mg (

𝑡

2)

Lateral acceleration 𝑀𝑉2

𝑅 h = Mg

𝑡

2 …………………………………….1

The lateral forces at the center of gravity

𝑀𝑉2

𝑅 =

Mg t

2ℎ…………………………..A

The side forces at front tyre

YF = Mg t

2ℎ (

𝑏

𝑎+𝑏)…………………….2

At rear tyre,

YR = 𝑀𝑔𝑡

2ℎ (

𝑎

(𝑎+𝑏))…………………..3

Now the structure can be considered as a simply supported beam subject to lateral loading in

xy plane through the Centre of gravity.

Normal driving conditions never approach this situation because when height h (the height of

the center of gravity from a road surface datum.)

A modern car is typically 0.51m and track is 1.45m.

Lateral acceleration = 𝑔𝑡

2ℎ=

𝑔(1.45)

2(0.51)= 1.42 g

From equations 1 & A

We get, the lateral acceleration is 1.42 times of gravitational acceleration.

Note:

This does not occur as conventional road tyre side forces limit lateral acceleration to about is

0.75g. [3]

5. Fore and aft loading (Longitudinal loading):

During the acceleration and braking longitudinal forces are generated along the x-axis.

If the Centre of gravity of the vehicle is above the road surface the inertia force provides a load

transfer from one axle to another. While accelerating, the weight is transferred from front to

rear axle and vice versa for breaking or decelerating condition. To obtain a complete view of

43

all the forces acting on the body the heights of the centers of gravity of all components will be

required.

As the height, gravity of the components are unknown, we will not be able to plot the bending

moments for the vehicle.

Let us consider a simplified model of the vehicle where the center of gravity can provide useful

information about the local loading at the axle positions due to traction and breaking forces.

For the above figure, for the front wheel drive acceleration the forces due to traction and

braking are

(a) Front wheel drive, the reaction on the driving wheel is given as

RF = 𝑀𝑔 (𝐿−𝑎)−𝑀ℎ(

𝑑𝑣

𝑑𝑡)

𝐿 …………………………… A

(b) Rear wheel drive, the reaction on the driving wheel is

RR =

𝑀𝑔+𝑀ℎ(𝑑𝑣

𝑑𝑡)

𝐿 …………………………………………………………… B

44

(c) Braking case, the reaction on the axle are:

RF =

𝑀𝑔(𝐿−𝑎)+𝑀ℎ(𝑑𝑣

𝑑𝑡)

𝐿 ………………………………………………….C

6. Asymmetric Loading:

This type of loading occurs when one wheel strikes a raised object or drops into a hole that has

a raised edge. The resulting loads are vertical and longitudinal applied at one corner of the

vehicle. This condition is very complex loading on the entire vehicle structure. The magnitude

of the force excreted on the wheel and hence throughout the suspension to the structure will

depend upon [3]

Vehicle speed

Suspension stiffness

Wheel mass

Body mass

As the shock force is applied for a very period it can be assumed that the wheel continuous in

a steady speed. Therefore, the shock force Ru acts through the wheel center

The horizontal component will be

Rux = Ru Cos α

The vertical component will be

Ruz = Ru Sin α

45

The angle α is approximately

α = Sin-1 (rd-hu)/rd

Note: Assuming the tyre does not deflect excessively, the horizontal component will increase

relative to the vertical for small radius wheels.

Considering, the vertical loads on its own causes an additional axle load, inertial load through

the vehicle center of mass and a torsion moment on the vehicle structure.

Similarly, considering horizontal loads on its own as seeing the above figure (c) the addition

bending in the vertical plane x-z and a moment about the z axis are applied to the structure.

Hence, from the structural loading this load can be analyzed by the superposition of the 4 load

conditions. [3]

CES EduPack Results:

Density Vs. Tensile Strength:

46

By comparing the material properties of Density and Tensile strengths of, High Carbon Steel,

Age-hardening wrought Al alloy, Wrought Magnesium Alloy, Polyester, glass fiber reinforced

polymer epoxy matrix, carbon fiber reinforced plastics epoxy matrix for manufacture of the

structural chassis frame, we observed from the above graph that the material high carbon steel

has the highest density and tensile strength when compared with the rest of the materials but

as it is very heavy when compared to the rest of the materials. Hence, we do not select High

Carbon steel as the best suitable material for manufacture of the structural chassis frame.

In the same way polyester, can be observed as having the least density and tensile strength is

also not preferred as to be selected as the best material for manufacture of the chassis frame.

After careful study of these results we have concluded that Carbon fiber reinforced plastics

epoxy matrix is the best suitable material for manufacture of the structural frame of the chassis

as it has the ideal density, tensile strength, and weight.

Compressive Strength Vs. Price (SEK):

By comparing the compressive strength and price in SEK for all materials listed above we can

observe that High carbon steel has the least price in SEK and with most compressive strength,

but due to its other numerous demerits as observed above make it not the ideal material for

selection for manufacture of the structural chassis frame. After carefully analyzing all these

materials, based on their properties and price in SEK we select Carbon fiber reinforced plastics

as the ideal material for manufacture of the structural chassis frame.

47

Project

First Saved Wednesday, October 26, 2016

Last Saved Wednesday, October 26, 2016

Product Version 15.0 Release

Save Project Before Solution No

Save Project After Solution No

48

Contents

Units

Model (A4) o o Geometry

Parts o Coordinate Systems o Connections

Contacts Contact Regions

o Mesh o Static Structural (A5)

Analysis Settings Loads Solution (A6)

Solution Information Results

Units

TABLE 1

Unit System Metric (m, kg, N, s, V, A) Degrees rad/s Celsius

Angle Degrees

Rotational Velocity rad/s

Temperature Celsius

Model (A4)

Geometry

TABLE 2 Model (A4) > Geometry

Object Name Geometry

State Fully Defined

Definition

Source C:\Users\Anoop\Desktop\CATIA FILES\Chassis Master.step

Type Step

Length Unit Meters

Element Control Program Controlled

49

Display Style Body Color

Bounding Box

Length X 2.791 m

Length Y 1.48 m

Length Z 2.0994 m

Properties

Volume 0.11483 m³

Mass 901.38 kg

Scale Factor Value 1.

Statistics

Bodies 25

Active Bodies 25

Nodes 275471

Elements 183583

Mesh Metric None

Basic Geometry Options

Solid Bodies Yes

Surface Bodies Yes

Line Bodies No

Parameters Yes

Parameter Key DS

Attributes No

Named Selections No

Material Properties No

Advanced Geometry Options

Use Associativity Yes

Coordinate Systems No

50

Reader Mode Saves Updated File No

Use Instances Yes

Smart CAD Update No

Compare Parts on Update No

Attach File Via Temp File Yes

Temporary Directory C:\Users\Anoop\AppData\Local\Temp

Analysis Type 3-D

Mixed Import Resolution None

Decompose Disjoint Geometry Yes

Enclosure and Symmetry Processing Yes

TABLE 3 Model (A4) > Geometry > Parts

Object

Name

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chass

is

Maste

rs v2

v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chass

is

Maste

rs v2

v1

Chass

is

Maste

rs v2

v1

Chassi

s

Master

s v2 v1

Chass

is

Maste

rs v2

v1

Chass

is

Maste

rs v2

v1

Chass

is

Maste

rs v2

v1

State Meshed

Graphics Properties

Visible Yes

Transpare

ncy 1

Definition

Suppresse

d No

Stiffness

Behavior Flexible

Coordinate

System Default Coordinate System

Reference

Temperatu

re

By Environment

Thickness 2.e-002 m

51

Thickness

Mode Manual

Offset

Type Middle

Material

Assignmen

t Carbon Fiber

Nonlinear

Effects Yes

Thermal

Strain

Effects

Yes

Bounding Box

Length X 4.e-002 m 0.65841 m 4.e-002 m 1.2195 m

Length Y 4.e-002 m 0.64 m 1.48 m 0.51981 m 4.e-002 m

Length Z 1.3035 m 1.6196

m

2.0794

m 2.0136 m 1.3035 m 1.3305 m

Properties

Volume 3.2743e-003 m³

8.7551

e-003

m³

1.1879

e-002

m³

5.9124e-003

m³

3.2743e-003

m³

4.4336e-003

m³

Mass 25.704 kg 68.728

kg

93.248

kg 46.412 kg 25.704 kg 34.804 kg

Centroid X

5.3932

e-019

m

1.2446

e-019

m

2.987

e-018

m

0.3680

1 m

2.1287

m 2.6122 m

2.751

m

0.938

7 m 1.5337 m

Centroid Y -0.3 m 0. m 0.3 m

6.3999

e-006

m

1.4033

e-005

m

-

0.505

8 m

0.505

8 m

-

8.2972

e-019

m

0.72 m -0.72

m

Centroid Z 0.65176 m 0.444

m

0.1792

1 m 0.20587 m 0.65176 m

Moment of

Inertia Ip1 3.6362 kg·m²

21.421

kg·m²

69.195

kg·m² 17.872 kg·m² 3.6362 kg·m² 9.0211 kg·m²

Moment of

Inertia Ip2 3.6362 kg·m²

16.207

kg·m²

35.029

kg·m² 18.74 kg·m² 3.6362 kg·m² 9.0211 kg·m²

52

Moment of

Inertia Ip3 1.0141e-002 kg·m²

5.2411

kg·m²

34.203

kg·m²

0.88614

kg·m²

1.0141e-002

kg·m²

1.3731e-002

kg·m²

Surface

Area(appro

x.)

0.16372 m² 0.4377

6 m²

0.5939

3 m² 0.29562 m² 0.16372 m² 0.22168 m²

Statistics

Nodes 1460 1488 1500 4560 5696 3045 3071 1501 1488 2006 1992

Elements 1448 1476 1488 4552 5687 3033 3059 1490 1476 1995 1980

Mesh

Metric None

Object

Name

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chassi

s

Master

s v2 v1

Chass

is

Maste

rs v2

v1

Chass

is

Maste

rs v2

v1

Chass

is

Maste

rs v2

v1

State Meshed

Graphics Properties

Visible Yes

Transpare

ncy 1

Definition

Suppresse

d No

Stiffness

Behavior Flexible

Coordinate

System Default Coordinate System

Reference

Temperatu

re

By Environment

Thickness 2.e-002 m

Thickness

Mode Manual

53

Offset

Type Middle

Material

Assignme

nt Carbon Fiber

Nonlinear

Effects Yes

Thermal

Strain

Effects

Yes

Bounding Box

Length X 4.e-002 m 0.4065

1 m 4.e-002 m 0.40651 m

Length Y 1.44 m 4.e-

002 m 1.44 m

4.e-

002 m 0.6 m

0.6363

4 m 1.44 m 4.e-002 m

Length Z 4.e-

002 m

1.3035

m

4.e-

002 m

1.3144

m

4.e-

002 m

1.3202

m 4.e-002 m 1.3144 m

Properties

Volume

3.6172

e-003

m³

3.2743

e-003

m³

3.6172

e-003

m³

3.4023

e-003

m³

1.5072

e-003

m³

3.6046

e-003

m³

3.6172e-003

m³ 3.4023e-003 m³

Mass 28.395

kg

25.704

kg

28.395

kg

26.708

kg

11.831

kg

28.296

kg 28.395 kg 26.708 kg

Centroid X 2.1287

m 0.9387 m

0.1840

1 m

0.3680

1 m

-

3.5337

e-011

m

2.1287

m

0.9387

m 0.18401 m

Centroid Y

1.3099

e-016

m

-0.72

m

5.4078

e-018

m

0.3 m

-

5.4078

e-018

m

1.2257

e-009

m

1.3219

e-017

m

3.0043

e-018

m

0.3 m -0.3 m

Centroid Z 1.3035

m

0.6517

6 m

1.3035

m

0.6517

6 m

1.3035

m

0.6517

6 m

3.7554

e-019

m

2.2533

e-019

m

0.65176 m

Moment of

Inertia Ip1

4.9009

kg·m²

3.6362

kg·m²

4.9009

kg·m²

4.0791

kg·m²

0.3564

5

kg·m²

4.8498

kg·m² 4.9009 kg·m² 4.0791 kg·m²

54

Moment of

Inertia Ip2

1.1203

e-002

kg·m²

3.6362

kg·m²

1.1203

e-002

kg·m²

4.0791

kg·m²

4.6679

e-003

kg·m²

4.8498

kg·m²

1.1203e-002

kg·m² 4.0791 kg·m²

Moment of

Inertia Ip3

4.9009

kg·m²

1.0141

e-002

kg·m²

4.9009

kg·m²

1.0538

e-002

kg·m²

0.3564

5

kg·m²

1.1164

e-002

kg·m²

4.9009 kg·m² 1.0538e-002 kg·m²

Surface

Area(appr

ox.)

0.1808

6 m²

0.1637

2 m²

0.1808

6 m²

0.1701

2 m²

7.5358

e-002

m²

0.1802

3 m² 0.18086 m² 0.17012 m²

Statistics

Nodes 1596 1512 1667 1560 696 1645 1584 1620 1560 1621 1684

Elements 1584 1500 1656 1548 684 1634 1572 1608 1548 1610 1673

Mesh

Metric None

TABLE 5 Model (A4) > Geometry > Parts

Object Name Chassis Masters v2 v1 Chassis Masters v2 v1 Chassis Masters v2 v1

State Meshed

Graphics Properties

Visible Yes

Transparency 1

Definition

Suppressed No

Stiffness Behavior Flexible

Coordinate System Default Coordinate System

Reference Temperature By Environment

Thickness 2.e-002 m

Thickness Mode Manual

Offset Type Middle

Material

Assignment Carbon Fiber

55

Nonlinear Effects Yes

Thermal Strain Effects Yes

Bounding Box

Length X 4.e-002 m 2.791 m

Length Y 0.6 m 1.48 m

Length Z 4.e-002 m

Properties

Volume 1.5072e-003 m³ 9.5784e-003 m³

Mass 11.831 kg 75.19 kg

Centroid X 0.36801 m 1.4652 m

Centroid Y -1.2258e-017 m -3.1514e-009 m 2.0783e-011 m

Centroid Z 2.7039e-019 m 1.3035 m 3.1895e-012 m

Moment of Inertia Ip1 0.35645 kg·m² 23.747 kg·m²

Moment of Inertia Ip2 4.6679e-003 kg·m² 68.922 kg·m²

Moment of Inertia Ip3 0.35645 kg·m² 92.654 kg·m²

Surface Area(approx.) 7.5358e-002 m²

Statistics

Nodes 684 116081 114154

Elements 672 69855 68755

Mesh Metric None

Coordinate Systems

TABLE 6 Model (A4) > Coordinate Systems > Coordinate System

Object Name Global Coordinate System

State Fully Defined

Definition

Type Cartesian

Coordinate System ID 0.

56

Origin

Origin X 0. m

Origin Y 0. m

Origin Z 0. m

Directional Vectors

X Axis Data [ 1. 0. 0. ]

Y Axis Data [ 0. 1. 0. ]

Z Axis Data [ 0. 0. 1. ]

Connections

TABLE 7 Model (A4) > Connections

Object Name Connections

State Fully Defined

Auto Detection

Generate Automatic Connection On Refresh Yes

Transparency

Enabled Yes

TABLE 8 Model (A4) > Connections > Contacts

Object Name Contacts

State Fully Defined

Definition

Connection Type Contact

Scope

Scoping Method Geometry Selection

Geometry All Bodies

Auto Detection

Tolerance Type Slider

57

Tolerance Slider 0.

Tolerance Value 9.4827e-003 m

Use Range No

Face/Face Yes

Face/Edge No

Edge/Edge No

Priority Include All

Group By Bodies

Search Across Bodies

TABLE 9 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n

Conta

ct

Regio

n 2

Conta

ct

Regio

n 3

Conta

ct

Regio

n 4

Conta

ct

Regio

n 5

Contact

Region 6

Conta

ct

Regio

n 7

Conta

ct

Regio

n 8

Conta

ct

Regio

n 9

Conta

ct

Regio

n 10

Conta

ct

Regio

n 11

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 1 Face

Target 1 Face 2 Faces 1 Face

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell

Face

Program Controlled

Target

Shell

Face

Program Controlled

Program

Controlle

d

Program Controlled

Shell

Thickness

Effect

No

58

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppress

ed No

Advanced

Formulati

on Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

TABLE 10 Model (A4) > Connections > Contacts > Contact Regions

59

Object

Name

Conta

ct

Regio

n 12

Conta

ct

Regio

n 13

Conta

ct

Regio

n 14

Conta

ct

Regio

n 15

Conta

ct

Regio

n 16

Conta

ct

Regio

n 17

Conta

ct

Regio

n 18

Conta

ct

Regio

n 19

Conta

ct

Regio

n 20

Conta

ct

Regio

n 21

Contact

Region

22

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 1 Face 2 Faces 1

Face

4

Faces

2

Faces

4

Faces 3 Faces

Target 2 Faces 1 Face 4 Faces 1 Face

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell

Face

Program Controlled

Shell

Thickness

Effect

No

Target

Shell

Face

Program Controlled

Program

Controlle

d

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppress

ed No

60

Advanced

Formulati

on Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

TABLE 11 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n 23

Conta

ct

Regio

n 24

Conta

ct

Regio

n 25

Conta

ct

Regio

n 26

Conta

ct

Regio

n 27

Conta

ct

Regio

n 28

Conta

ct

Regio

n 29

Conta

ct

Regio

n 30

Conta

ct

Regio

n 31

Conta

ct

Regio

n 32

Conta

ct

Regio

n 33

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 3

Faces 1 Face

2

Faces

4

Faces

2

Faces

4

Faces 1 Face

2

Faces 1 Face

2

Faces

Target 1 Face 4 Faces 2 Faces

Contact

Bodies Chassis Masters v2 v1

61

Target

Bodies Chassis Masters v2 v1

Contact

Shell Face Program Controlled

Target

Shell Face Program Controlled

Shell

Thickness

Effect

No

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppresse

d No

Advanced

Formulatio

n Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

62

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

TABLE 12 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n 34

Conta

ct

Regio

n 35

Conta

ct

Regio

n 36

Conta

ct

Regio

n 37

Conta

ct

Regio

n 38

Conta

ct

Regio

n 39

Conta

ct

Regio

n 40

Conta

ct

Regio

n 41

Conta

ct

Regio

n 42

Conta

ct

Regio

n 43

Conta

ct

Regio

n 44

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 1 Face

Target 1 Face 2 Faces 1 Face 2 Faces

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell Face Program Controlled

Shell

Thickness

Effect

No

Target

Shell Face Program Controlled

Program

Controlled

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

63

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppresse

d No

Advanced

Formulatio

n Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

TABLE 13 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n 45

Conta

ct

Regio

n 46

Conta

ct

Regio

n 47

Conta

ct

Regio

n 48

Conta

ct

Regio

n 49

Conta

ct

Regio

n 50

Conta

ct

Regio

n 51

Conta

ct

Regio

n 52

Conta

ct

Regio

n 53

Conta

ct

Regio

n 54

Conta

ct

Regio

n 55

State Fully Defined

Scope

64

Scoping

Method Geometry Selection

Contact 1 Face

Target 1 Face 2 Faces 4

Faces 1 Face 2 Faces

4

Faces

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell Face Program Controlled

Target

Shell Face Program Controlled

Program

Controlled

Shell

Thickness

Effect

No

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppresse

d No

Advanced

Formulatio

n Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

65

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

TABLE 14 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n 56

Conta

ct

Regio

n 57

Conta

ct

Regio

n 58

Conta

ct

Regio

n 59

Contact

Region

60

Conta

ct

Regio

n 61

Conta

ct

Regio

n 62

Conta

ct

Regio

n 63

Conta

ct

Regio

n 64

Conta

ct

Regio

n 65

Conta

ct

Regio

n 66

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 1 Face

Target 1 Face 2 Faces 1 Face 4

Faces 1 Face 2 Faces

4

Faces

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell

Face

Program Controlled

Target

Shell

Face

Program

Controlled

Program

Controlle

d

Program

Controlled

66

Shell

Thickness

Effect

No

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

Suppress

ed No

Advanced

Formulati

on Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

67

TABLE 15 Model (A4) > Connections > Contacts > Contact Regions

Object

Name

Conta

ct

Regio

n 67

Contact

Region

68

Conta

ct

Regio

n 69

Conta

ct

Regio

n 70

Conta

ct

Regio

n 71

Conta

ct

Regio

n 72

Conta

ct

Regio

n 73

Conta

ct

Regio

n 74

Conta

ct

Regio

n 75

Conta

ct

Regio

n 76

Conta

ct

Regio

n 77

State Fully Defined

Scope

Scoping

Method Geometry Selection

Contact 1 Face

Target 4

Faces 1 Face 2 Faces 1 Face 2 Faces

4

Faces

Contact

Bodies Chassis Masters v2 v1

Target

Bodies Chassis Masters v2 v1

Contact

Shell

Face

Program Controlled

Shell

Thickness

Effect

No

Target

Shell

Face

Program

Controlle

d

Program

Controlled

Definition

Type Bonded

Scope

Mode Automatic

Behavior Program Controlled

Trim

Contact Program Controlled

Trim

Tolerance 9.4827e-003 m

68

Suppress

ed No

Advanced

Formulati

on Program Controlled

Detection

Method Program Controlled

Penetratio

n

Tolerance

Program Controlled

Elastic

Slip

Tolerance

Program Controlled

Normal

Stiffness Program Controlled

Update

Stiffness Program Controlled

Pinball

Region Program Controlled

Geometric Modification

Contact

Geometry

Correction

None

Mesh

TABLE 16 Model (A4) > Mesh

Object Name Mesh

State Solved

Defaults

Physics Preference Mechanical

Relevance 0

Sizing

Use Advanced Size Function On: Curvature

69

Relevance Center Coarse

Initial Size Seed Active Assembly

Smoothing Medium

Transition Fast

Span Angle Center Coarse

Curvature Normal Angle Default (30.0 °)

Min Size Default (8.7157e-003 m)

Max Face Size Default (4.3579e-002 m)

Max Size Default (4.3579e-002 m)

Growth Rate Default

Minimum Edge Length 6.2832e-002 m

Inflation

Use Automatic Inflation None

Inflation Option Smooth Transition

Transition Ratio 0.272

Maximum Layers 5

Growth Rate 1.2

Inflation Algorithm Pre

View Advanced Options No

Patch Conforming Options

Triangle Surface Mesher Program Controlled

Patch Independent Options

Topology Checking Yes

Advanced

Number of CPUs for Parallel Part Meshing Program Controlled

Shape Checking Standard Mechanical

Element Midside Nodes Program Controlled

70

Straight Sided Elements No

Number of Retries Default (4)

Extra Retries for Assembly Yes

Rigid Body Behavior Dimensionally Reduced

Mesh Morphing Disabled

Defeaturing

Pinch Tolerance Default (7.8441e-003 m)

Generate Pinch on Refresh No

Sheet Loop Removal No

Automatic Mesh Based Defeaturing On

Defeaturing Tolerance Default (6.5368e-003 m)

Statistics

Nodes 275471

Elements 183583

Mesh Metric None

Static Structural (A5)

TABLE 17 Model (A4) > Analysis

Object Name Static Structural (A5)

State Solved

Definition

Physics Type Structural

Analysis Type Static Structural

Solver Target Mechanical APDL

Options

Environment Temperature 22. °C

Generate Input Only No

71

TABLE 18 Model (A4) > Static Structural (A5) > Analysis Settings

Object Name Analysis Settings

State Fully Defined

Step Controls

Number of Steps 1.

Current Step Number 1.

Step End Time 1. s

Auto Time Stepping Program Controlled

Solver Controls

Solver Type Program Controlled

Weak Springs Program Controlled

Large Deflection Off

Inertia Relief Off

Restart Controls

Generate Restart Points Program Controlled

Retain Files After Full Solve No

Nonlinear Controls

Newton-Raphson Option Program Controlled

Force Convergence Program Controlled

Moment Convergence Program Controlled

Displacement Convergence Program Controlled

Rotation Convergence Program Controlled

Line Search Program Controlled

Stabilization Off

Output Controls

Stress Yes

Strain Yes

72

Nodal Forces No

Contact Miscellaneous No

General Miscellaneous No

Store Results At All Time Points

Analysis Data Management

Solver Files Directory C:\Users\Anoop\Desktop\Chassis_files\dp0\SYS\MECH\

Future Analysis None

Scratch Solver Files Directory

Save MAPDL db No

Delete Unneeded Files Yes

Nonlinear Solution No

Solver Units Active System

Solver Unit System mks

TABLE 19 Model (A4) > Static Structural (A5) > Loads

Object Name Force Fixed

Support

Force

2

Force

3

Force

4

Force

5

Force

6

State Fully Defined

Scope

Scoping Method Geometry Selection

Geometry 1 Face 10 Faces 1 Face

Definition

Type Force Fixed

Support Force

Define By Components Components

Coordinate

System

Global Coordinate

System Global Coordinate System

X Component 166.66 N (ramped) 166.66 N (ramped)

Y Component 0. N (ramped) 0. N (ramped)

73

Z Component 0. N (ramped) 0. N (ramped)

Suppressed No

FIGURE 2 Model (A4) > Static Structural (A5) > Force

FIGURE 3 Model (A4) > Static Structural (A5) > Force 2

74

FIGURE 4 Model (A4) > Static Structural (A5) > Force 3

FIGURE 5 Model (A4) > Static Structural (A5) > Force 4

75

FIGURE 6 Model (A4) > Static Structural (A5) > Force 5

FIGURE 7 Model (A4) > Static Structural (A5) > Force 6

Solution (A6)

TABLE 20 Model (A4) > Static Structural (A5) > Solution

Object Name Solution (A6)

State Solved

Adaptive Mesh Refinement

Max Refinement Loops 1.

Refinement Depth 2.

Information

Status Done

TABLE 21 Model (A4) > Static Structural (A5) > Solution (A6) > Solution Information

Object Name Solution Information

State Solved

Solution Information

Solution Output Solver Output

Newton-Raphson Residuals 0

76

Update Interval 2.5 s

Display Points All

FE Connection Visibility

Activate Visibility Yes

Display All FE Connectors

Draw Connections Attached To All Nodes

Line Color Connection Type

Visible on Results No

Line Thickness Single

Display Type Lines

TABLE 22 Model (A4) > Static Structural (A5) > Solution (A6) > Results

Object Name Total Deformation Equivalent Stress

State Solved

Scope

Scoping Method Geometry Selection

Geometry All Bodies

Shell Top/Bottom

Definition

Type Total Deformation Equivalent (von-Mises) Stress

By Time

Display Time Last

Calculate Time History Yes

Identifier

Suppressed No

Results

Minimum 0. m 0. Pa

Maximum 1.4411e-005 m 2.5479e+006 Pa

77

Minimum Occurs On Chassis Masters v2 v1

Maximum Occurs On Chassis Masters v2 v1

Minimum Value Over Time

Minimum 0. m 0. Pa

Maximum 0. m 0. Pa

Maximum Value Over Time

Minimum 1.4411e-005 m 2.5479e+006 Pa

Maximum 1.4411e-005 m 2.5479e+006 Pa

Information

Time 1. s

Load Step 1

Sub step 1

Iteration Number 1

Integration Point Results

Display Option Averaged

Average Across Bodies No

78

List of figures:

1. Fig:2.2.1 Flowchart of the project

2. Figure: 3.1.1 Ladder Frame [11]

3. Figure: 3.1.2 Backbone tube chassis [7]

4. Figure: 3.1.3 X- Frame or Cruciform Frame [3]

5. Figure: 3.1.4 Perimeter Frame [6]

6. Figure: 3.1.5 Space Frame [9]

7. Figure: 3.1.6 Uni-body Frame [10]

8. Figure: 3.1.7 Sub-Frame [8]

9. Fig 4.3.2 Wire frame of the chassis

10. Fig.4.3.3 Side view and top view of the tubular chassis structure

11. Fig. 4.3.4 Other different views of the tubular chassis structure

12. Fig. 4.3.5 Final tubular design of the chassis structure

13. Fig. 4.4.1 Chassis structure after importing into ANSYS 15.0 and applying material

with meshing generation on the structure.

14. Fig. 4.4.2 Applying of fixed support B (indicated by blue colour)

15. Fig.4.4.3 Applying Forces A, C, D, E, F and H of 166.66 N each on the chassis structure

along with fixed support B

16. Fig. 4.5.1 Deformation simulation of the chassis structural frame

17. Fig 4.5.2 Deformation distribution as observed in the chassis deformation simulation

List of Tables:

1. Table:4.1.1: House of Quality: (QFD for Type of Chassis Selection) [1]

2. Table: 4.2.1: House of Quality: (QFD for Material Selection) [1]

3. Table:4.3.1 Design parameters

PO Box 823, SE-301 18 HalmstadPhone: +35 46 16 71 00E-mail: registrator@hh.sewww.hh.se

Anoop Bharadwaj Yellambalse PremKumar,yanoopbharadwaj@yahoo.com+46 734915357

Pavan Kumar Maareddygaripavi.friend123@gmail.com+46 764428212