MODELLING AND ANALYSIS OF DISC BRAKE ROTOR

A Thesis

Submitted to

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY ANANTAPUR, ANANTAPURAMU

In partial fulfillment of the requirements for the award of the Degree

of

BACHELOR OF TECHNOLOGY

In

MECHANICAL ENGINEERING

Academic Batch 2011-15

By

G.SUDHEER (114M1A0328) L.SAI PRATAP (114M1A0323)

Y.ASHOK (114M1A0302)G.GURU PRASAD (114M1A0310)

Under the Guidance of

Mrs. K.BALAJI M.Tech

Assistant Professor, VEMU INSTITUTE OF TECHNOLOGY – Chittoor

DEPARTMENT OF MECHANICAL ENGINEERINGVEMU INSTITUTE OF TECHNOLOGY

(Approved by AICTE, New Delhi & Affiliated to JNTU,Anantapur)

P. K o t h a k o t a (P), P u t h a l a p a t t u (M), C h I t t o o rDist. - 517112

VEMU INSTITUTE OF TECHNOLOGY(Approved by AICTE, New Delhi & Affiliated to JNTU,

Anantapur)P. K o t h a k o t a (P), P u t h a l a p a t t u (M), C h I t t o o r

Dist. - 517112DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

This is to certify that the Project report entitled “MODELLING AND

ANALYSIS OF DISC BRAKE ROTOR” is a bonafide work carried out by

G.SUDHEER(114M1A0328)

L.SAI PRATAP(114M1A0323) Y.ASHOK(114M1A0302) G.GURU PRASAD

(114M1A0310)

during the academic batch 2011-15 is submitted to the department of

Mechanical Engineering, in partial fulfillment of the requirements

for the award of degree of BACHELOR OF TECHNOLOGY in MECHANICAL

ENGINEERING from Jawaharlal Nehru Technological University Anantapur,

Ananthapuramu.This is a record of bonafide work carried out by the

above student on his own and the results embodied in this project have

not been reproduced or copied from any source. The results embodied in

this project report have not been submitted to any other university or

institute for the award of any other degree or diploma.

Signature of the Supervisor Signature of the Head of the Department

Mr.K.Balaji, Mr.S.P.Bhanu murthy,Assistant Professor Professor& HODDepartment of Mechanical Engineering, Department of Mechanical Engineering,VIT, Chittoor. VIT, Chittoor. External Viva-Voce held on: ____________

Signature of the Internal Examiner Signature of the

External Examiner

VEMU INSTITUTE OF TECHNOLOGY(Approved by AICTE, New Delhi & Affiliated to JNTU,

Anantapur)P. K o t h a k o t a (P), P u t h a l a p a t t u (M), C h I t t o o r

Dist. - 517112

DEPARTMENT OF MECHANICAL ENGINEERING

DECLARATION

We,G.Sudheer (114M1A0328)

L.Sai pratap (114M1A0323)

Y.Ashok (114M1A0302)

G.Guru Prasad (114M1A0310)

Here by declare that the Project report entitled “MODELLING AND

ANALYSIS OF DISC BRAKE ROTOR”” under the guidance of Mrs.K.Balaji,

Assistant Professor, Vemu Institute of Technology,, Chittoor is

submitted in partial fulfillment of the requirements for the award of

the degree of BACHELOR OF TECHNOLOGY in MECHANICAL ENGINEERING.This is

a record of bonafide work carried out by me and the results embodied

in this project have not been reproduced or copied from any source.

The results embodied in this project report have not been submitted to

any other university or institute for the award of any other any

degree or diploma

other degree or diploma.

Signature of the student

ACKNOWLEDGEMENT

This project has been successful with the encouragement, guidance

and support attributed from many patrons along with the hard work that

has been put into it by myself. I would like to take this opportunity

to express my gratitude and sincere thanks to all those who made this

project a successful one.

It is my great pleasure to express my sincere thanks to

Mr.S.P.Bhanu murthy, M.Tech HOD – Mechanical Engineering Department for

his valuable suggestions related to the different aspects of this

project.

I am extremely thankful and immensely grateful to my guide

Mr.K.Balaji, M.Tech VIT for granting me this golden opportunity to

complete my project work under her esteemed guidance. Her keen

interest, continuous encouragement and regular supervision at every

stage of this project have ensured the best out of me and the best

possible results from the project. Finally, yet importantly, I would

like to express my sincere thanks to all my respectable faculties,

respected parents, dear friends and classmates for their support,

blessings, help and continuous encouragement for the successful

completion of this project.

,G.Sudheer (114M1A0328)

L.Sai pratap (114M1A0323)

Y.Ashok (114M1A0302)

G.Guru Prasad (114m1a0310)

ABSTRACT

The disc brake is a device for slowing or stopping the rotation of a

wheel. Breaks convert friction into heat if brake get to hot they will

expose to large thermal stress during the rotation of breaking. Break

is a mechanical device is used stop are slowing of vehicle during the

motion. The main aim of this project is to minimize the temperature

and thermal stress with best suited Material Analysis is done on both

ventilated and normal disc Actual disc brake has no holes design is

changed by giving holes in the disc brake for more heat dissipation.

Modeling is done in catia v5 and analysis is done in analysis is

done ansys 2012 (finite element Analysis software) thermal and

structural analysis is done by providing materials gray cast iron And

stain less steel and comparing both results and providing best suited

material.

Table of Contents

ACKNOWLEDGEMENT…………………………………………………………….i

ABSTRACT................................................i

Table of Contents.....................................iii

List of Tables.........................................vi

List of Figures.......................................vii

1 INTRODUCTION...................................1

1.1 BRAKEING SYSTEM ...............................1

1.1.1 PRINCIPLE OF BRAKEING SYSTEM.................1

2 LITERATURE REVIEW..............................4

2.1 HISTORY OF BREAKING SYSTEM.....................4

2.1.1 TYPICAL MODERN AUTOMOTIVE BRAKE SYSTEM.........5

2.2.2 TYPES OF DISC BRAKE ROTORS.....................6

2.2.3 USES OF ROTOR..................................9

2.2.4 FUNCTIONS OF DISC BRAKE ROTOR..................9

2.3 MANUFACTURING PROCESS OF LEAF SPRING..........14

2.3.1 STEPS IN MANUFACTURING PROCESS OF LEAF SPRING. 15

2.4 SPRING MATERIALS..............................19

2.4.1 HIGH CARBON STEELS............................20

2.4.2 ALLOY STEELS..................................20

2.4.3 STAINLESS STEELS..............................20

2.4.4 COPPER-BASED ALLOYS...........................21

2.4.5 NICKEL-BASED ALLOYS...........................21

2.4.6 COMPOSITE MATERIALS...........................21

2.4.7 ADVANTAGES OF COMPOSITE MATERIALS.............22

2.4.8 DISADVANTAGES OF COMPOSITE MATERIALS..........23

2.4.9 STEEL VS COMPOSITE MATERIALS..................23

2.5 ADVANTAGES OF LEAF SPRING.....................24

2.6 DISADVANTAGES OF LEAF SPRING..................25

3 METHODOLOGY...................................28

3.1 INTRODUCTION..................................28

3.2 SPECIFICATION OF PROBLEM......................29

3.3 GEOMETRY IN SOLID WORKS.......................30

3.3.1 STEPS TO DRAW THE LEAF SPRING ASSEMBLY IN SOLID WORKS 14

..............................................30

3.3.2 SPECIFICATIONS OF SEMIELLIPTICAL LEAF SPRING ASSEMBLY 31

3.3.3 MODEL OF THE MASTER LEAF SPRING...............32

3.3.4 ASSEMBLY VIEW OF LEAF SPRING ASSEMBLY.........32

3.3.5 BOTTOM VIEW OF LEAF SPRING ASSEMBLY...........33

3.3.6 ISOMETRIC VIEW OF LEAF SPRING ASSEMBLY........33

3.4 IMPORT OF CAD MODELS IN ANSYS.................33

3.5 MESHING OF GEOMETRY...........................34

3.6 BOUNDARY CONDITIONS...........................36

3.7 MATERIAL PROPERTIES...........................36

4 RESULTS AND DISCUSSION........................37

4.1 DEFORMATION RESULTS...........................37

4.1.1 STAINLESS STEEL...............................37

4.1.2 CARBON FIBRE..................................38

4.1.3 BORON FIBRE...................................38

4.2 STRESS RESULTS................................39

4.2.1 STAINLESS STEEL...............................39

4.2.2 CARBON FIBRE..................................40

4.2.3 BORON FIBRE...................................40

4.3 STRAIN RESULTS................................41

4.3.1 STAINLESS STEEL...............................41

4.3.2 CARBON FIBRE..................................42

4.3.3 BORON FIBRE...................................42

4.4 RESULTS OF INDIVIDUAL LEAVES..................43

4.5 FEA RESULTS...................................44

4.6 ANALYTICAL CALCULATIONS.......................45

4.6.1 STAINLESS STEEL...............................45

4.6.2 CARBON FIBRE..................................45

4.6.3 BORON FIBRE...................................46

4.7 ANALYTICAL RESULTS............................47

5 CONCLUSION....................................48

6 FUTURE SCOPE..................................49

7 REFERENCES………………………………………………………..50

8 PAPER PUBLISHED……………………………………………………...51

List of Tables

Table 3-1: Specifications of semielliptical leaf spring assembly 31

Table 3-2: Mechanical properties of materials..........36

Table 4-1: FEA results.................................44

Table 4-2: Analytical results..........................47

List of Figures

Figure 3-1: Flowchart for methodology..................29

Figure 3-2: Model of the master leaf spring............32

Figure 3-3: Assembly view of leaf spring assembly......32

Figure 3-4: Bottom view of leaf spring assembly........33

Figure 3-5: Isometric view of leaf spring assembly.....33

Figure 3-6: Importing model of leaf spring.............34

Figure 3-7: Meshing of leaf spring assembly............35

Figure 3-8: Detailed view of meshing...................35

Figure 3-9: Boundary condition of leaf spring..........36

Figure 4-1: Deformation in stainless steel.............37

Figure 4-2: Deformation in carbon fibre................38

Figure 4-3: Deformation in boron fibre.................38

Figure 4-4: Stress in stainless steel..................39

Figure 3-5: Stress in carbon fibre.....................40

Figure 4-6: Stress in boron fibre......................40

Figure 4-7: Strain in stainless steel..................41

Figure 4-8: Stress in carbon fiber.....................42

Figure 4-9: Strain in boron fibre......................42

CHAPTER IINTRODUCTION

1.1 BREAKING SYSTEM Brakes are the most important safety parts

in the vehicles. Generally all of the vehicles have their own safety

devices to stop their car. Function of brakes to slow and stop the

rotation of the wheel. To stop the wheel, breaking pads are forced

mechanically against rotor disc on both surfaces .they compulsory for

all of the modern vehicles and the safe operation of vehicles. Brakes

transform the kinetic energy of the car into heat energy.

Brakes have been retuned and improved ever since their invention.

Brakes increases in the travelling speeds. An effective braking system

is needed to accomplish this task with challenging term where material

need to be lighter than before and performance of the brakes must be

improved. Today’s cars often use a combination of disc brakes and drum

brakes.

Disc brakes are located on front two wheels and drum brakes on

the back two wheels. Clearly show that together with steering

components and tiers represent the most important accident avoidance

systems present on motor vehicles.

In order to understand the behavior of braking system have to

satisfied following three function

1 The braking system must be permitted the vehicle to maintain a

constant speed when travelling

2 Break should control the vehicle in repeatable fashion and cause

the vehicle stop

3 The break should must hold the vehicle stationary when on the

flat or on a gradient

1.1.1 PRINCIPLE OF BRAKING SYSTEM

A brake is a device by means of which artificial frictional

resistance is applied to moving machine member, in order to stop the

motion of a machine. Break play major role in moving auto motive

vehicles

A disk brake consists of a cast iron disc bolted to the wheel hub

and a stationary hosing called caliper the caliper is connected to

some stationary part of the vehicle like the axle casing or stub axle

as in two parts each part containing a piston. in between each piston

and the disc there is a friction pad held in position by retaining

pins, spring plates etc. passages are drilled in the caliper for the

fluid enter or leave each housing the passages are also connected to

another one for bleeding . Each cylinder and piston.

When the brakes are applied, hydraulically actuated pistons move

the friction pads in to contact with the rotating disc, applying equal

and opposite forces on the disc. Due to the friction between disc and

pad surfaces the kinetic energy of the rotating wheel is converted

into heat, by which vehicle is to stop after a certain distance. On

releasing the brakes the brakes rubber-sealing ring acts as return

spring and retract the pistons and the friction pads away from the

disc. In the course of brake operation, frictional heat is dissipated

mostly pad and disc causes uneven temperature distribution on the

components could induce severe thermo elastic distortion of the disc.

The thermal distortion of a normally flat surface into highly deformed

state called thermo elastic transition. It sometimes occurs in the

sequence of stable continuously related states operating conditions

change. At the other times, however the stable evolution behavior of

the sliding system crosses threshold where upon a sudden change of

contact conditions occurs in a sequence of stable continuously related

states s operating conditions change.

When this process leads to an accelerated change of contact

pressure distribution, the unexpected hot roughness of thermal

distortion may grow unstably under some conditions, resulting in local

hot spots and leaving thermal cracks on the disc. This is known as

thermo elastic in stability. The thermo elastic instability phenomenon

occurs more easily as the rotating speed of the disk increases. This

region where the contact load is concentrated reaches very high

temperatures, which cause deterioration in braking performance.

Moreover, in the course of their presence on the disk, the passage of

thermally distorted hot spots moving under the brake pads causes low-

frequency brake vibration.

Figure 1.1; hydraulic disc brake

CHAPTER 2

2 LITERATURE REVIEW

2.1 INTRODUCTIONNormally, thermal stress analysis has been performed to any of

material related to thermal process in order to oversee the behavior

and character of material. Any abnormality regards to thermal input

will give the high values on the stress magnitude of the studied

materials.

The high values of stress magnitude will shows deformation on

certain areas which load has been applied on it. Design and analysis

of certain parts or component will took much time and it is costly.

Therefore, without any analysis or design tools, it would be

limitations on repeated analysis. For decades, finite element analysis

(FEA) has been a preferred method to address some of the above

concerns. It can be used to compare the design alternatives and hence,

optimize the brake rotor design prior to production of prototype

components.

A literature review was conducted to investigate the past

research that has been done in many areas related to this work. In

addition, description, histories, functions and theory of disc brake

rotor will be discussed in this chapter. Furthermore, theory of finite

element method related to thermal analysis will be presented as well

in this chapter

2.1.1 Some Brake History

The first known vehicular brake, the Locked Wheel

Figure 2-1; first know vehicular brake locked wheel

It is believed that the Romans used a chariot brake. One end of

chain was attached to a chariot chassis, while the other end was held

by the driver. The major advance of this brake was that it allowed the

amount of braking force to be varied.

Figure 2-2; chariot brake by using chain

Another advance was in the 1800’s. The typical wagon used a

wooden brake shoe that was pressed against the wheel rim by lever-

operated linkages.

Figure 2-3; wagon with wooden brake shoe

The first automobiles were little more than wagons or carriages

fitted with engines and drive trains. With the invention of rubber

tires, the rim-contact wagon brake became impractical. To solve the

problem, a metal brake drum was attached to the inside of the wheel to

provide a rubbing surface for the brake shoe.

Figure 2-4; rim contact wagon brake with metal brake drum

As time went by, the speeds attained by the newer models exceeded

the ability of the brakes to stop them safely and reliably (too much

energy into heat raising temperatures causing brake power loss and

quick wear out). Initial solution was to increase the surface area of

the lining material led to the band brake.

Figure 2-5; advance breaking system with brake lining

The solution for the problems of the band brake was the hydraulic

actuated internal expanding shoe brake.

Figure 2-6; hydraulic actuated internal expanding shoe brake

As highway speeds and the size and weight of vehicles continued

to increase, it became apparent that even the largest practical drum

brakes were unable to adequately transfer the heat generated during

repeated braking. Hence disc brakes became more in use.

Figure 2-7; drum brake

2.1.2 Typical Modern Automotive Brake System

Figure 2-8; typical modern automotive brake system

2.1.3 Basic Brake Operation

An automobile’s brake system must be able to slow or stop the vehicle

when in motion and it must be able to hold the car in position when

stopped on an incline.

Automotive brakes have two interrelated systems:1) Service Brakes

2) Parking Brakes

Basic Brake OperationAll break systems work in accordance with the physical “laws” or

principles that describe the relationships between elements of our

physical world such as

Energy

Inertia

Hydraulics

Mechanics

Friction

Energy:

Can be defined as the ability to do work

Work:

Transfer of energy from one physical system to another –

especially the transfer of energy to an object through the application

of force. Formula: Work = Force x Distance

Automotive Brakes:

The force input by the driver is multiplied by the actuation

system and enables the energy of the vehicle’s motion to be

transferred to the brake drums or rotors where friction converts it

into heat energy and stops the vehicle.

Kinetic Energy:

the energy of mass in motion the amount of that energy is

determined by the object’s mass and speed. Kinetic Energy is based on

speed and mass, not weight. Weight is the mass of an object acted upon

by the force of gravity. Since the force of gravity is relatively

constant on Earth, we can use the terms weight and mass

interchangeably in this tutorial. Weight and speed contribute to

kinetic energy – they do not affect it to the same degree – speed has

a much greater effect.

WEIGHT TRANSFER INCREASES THE LOAD ON THE FRONT WHEELS WHILE THE LOAD

ON THE RARE WHEELS REDUCED

For the foundation brakes to convert kinetic energy into heat

they must be applied with great force. The force required to stop a

vehicle is so great that leverage and hydraulics are used to

facilitate a person to apply it (We’ll not consider boosters in this

tutorial). The primary mechanical principle used to increase the

application force in every brake system is leverage. Lever: a simple

machine that consists of a rigid object that pivots about a fixed

point called a fulcrum.

In addition to mechanical advantage, hydraulic principles are

used to increase the brake application force. Hydraulic systems are

very efficient at transmitting motion and force. Hydraulic systems use

liquids to transmit motion (by moving a volume of the liquid). For all

practical purposes, a liquid cannot be compressed. A gas, such as air,

will compress and a hydraulic system MUST be free from air to work

properly.

Figure 2-9; hydraulic brake system with cylinder

Brake hydraulic systems not only transmit motion they also

transmit force in the form of pressure. Pressure in a brake system is

primarily determined by 2 factors (Not including the booster’s power

assist):

1) Force on the brake pedal multiplied by the mechanical advantage of

the pedal ratio.

2) Surface area of the master cylinder piston.

The differences in force are obtained by using different sized

pistons in the wheel cylinders and/or calipers. The ability of a

hydraulic system to increase and decrease forces appears to be a

convenient thing. However, there is another side to the process that

must be considered.

Brake linings having a coefficient of friction of less than 1.0

are not a deficiency. They have to be easily controlled as not being

“grabby” and not wear out too quickly while managing the heat

generated. The amount of contact width may not greatly affect the

coefficient of friction, but it does offer considerable effects on

lining life and the dissipation of heat converted from the vehicle’s

kinetic energy.

2.1.4 WHY DISC BRAKE NEED The higher levels of braking performance specified in the 1976

revision of FMVSS 105 virtually guaranteed that manufactures would use

only disc brakes on front axles of new vehicles.

The main performance advantages are:

Fade resistance (Both for high temperature and water soaking) Reduced tendency for pull (stay within 12 ft. lane requirement).

Lining Fade:

The lining material overheats, its friction coefficient drops and

lining fade occurs. Primary symptom is a hard pedal and requires the

driver to apply greater force to maintain stopping power. Point at

which it occurs in disc brakes is much later than in drum brakes and

recovery is faster.

Fade Resistance:

A disc brake compared to a drum brake of similar diameter has a

greater ability to resist fade. One reason for this is the cooling

ability since all the major parts are usually exposed to air flowing

over them. Also, many rotors have cooling passages cast into them to

help reduce operating temperatures. However, with the demands for high

number of multiple stops temperature requirements on today’s vehicles,

this is an area where the OEM’s need more R&D for improved heat

transfer (air flow) to transfer the heat into the atmosphere.

2.1.5 DISC BRAKE TYPES AND CALIPER BODYThere are many different designs but all contain the following basic

parts:

Caliper body Bleed Screw Pistons Piston seals Dust boots Pads

Fixed Caliper:

Body usually manufactured in two halves; has two, three or four

pistons Gets its name from the fact that it is rigidly mounted to the

knuckle; no part of the caliper body moves when the brakes are

applied.

Advantages:

Size and rigid mounting does not flex much. Strong and provides a firm and linear brake pedal feel. Strength and heat dissipating ability ideal for heavy duty use.

Disadvantages:

Weight, cost and complexity usually cannot be justified for the lower speeds and more moderate braking in U.S.

More difficult to service with more opportunity for leaks.

Fixed Caliper Alignment:

Must be centered over the rotor and aligned for pistons to

contact the pads parallel to the rotor If not properly aligned,

pistons will be at an angle and cause taper wear of the linings and if

too much misalignment, pistons could cock in their bores causing wear

and possibly cracking.

Figure 2-10; fixed caliper alignment

Floating / Sliding Calipers:

Not rigidly mounted, are free to move within a limited range on

an anchor that is solidly mounted to the vehicle Anchor may be cast

into the knuckle or it can be a separate piece that bolts on

Figure 2-11; floating/sliding caliper

When floating / sliding disc brakes are applied the caliper

piston moves out of its bore and forces the inner pad against the

rotor while the pressure on the closed end of the bore moves the

caliper body in the opposite direction forcing the outer pad against

the rotor at the same time. The caliper body moves every time the

brakes are applied

Floating / Sliding Calipers Advantages:

Biggest advantages are lower cost, simple construction and

compact size.

Fewer pieces: cost effective to build and service with fewer

potential leak points.

Smaller size usually allows better packaging on the vehicle (less

room required on the outboard side at the wheel).

Better suited for parking brake role. Can be mechanically

actuated by applying a single inboard piston with a cable and

lever mechanism.

Floating / Sliding Calipers Disadvantages:

Allows a degree of flex in the caliper suspension which may

contribute to a slight spongy pedal feel.

Caliper suspension flex also allows the body to twist slightly

when brakes are applied which cause taper lining can wear.

Do not have the mass of fixed calipers and the flexible mounting

systems slow the transfer of heat from the caliper body to the

anchor plate and other vehicle components that aid the cooling

Process.

2.1.6 DISC BRAKE PADS

Brake Pads:

Contact the rotor to create the friction that converts kinetic

energy into heat when stopping the vehicle Two pads are used in a disc

brake: one on each side of the rotor Designed and manufactured in all

sorts of various shapes and sizes usually to fit the package space

available while maximizing lining area and volume for optimum lining

life All have a metal backing plate (usually steel) to which lining is

molded or riveted.

Disc brake pads operate under the most extreme conditions in the

entire brake system and are subject to a great deal of temperature

variations and contaminants. Although they appear to be simple parts,

modern disc brake pads are the result of years of engineering and

development.

Friction Material:

The most important part of disc brake pads from an overall brake

performance perspective. Different brake designs require different

kinds of friction material. Disc brakes routinely operate at much

higher temperature than drum brakes and require pad friction material

to have a greater

resistance to this high temperature.

2.1.7 DISC BRAKE ROTORRotors are the largest and heaviest parts of the disc brake assembly.

They provide friction surfaces for the linings to rub against and

together these parts create the “friction couple” that converts

kinetic energy into heat and stops the vehicle. They absorb and

dissipate most of the heat generated in breaking Made of cast iron

because of its relative low cost good wear and friction properties and

ease of machining.

Figure 4-2; disc brake rotor

2.1.8 TYPES OF DISC ROTORSSolid Rotor:

One whose friction surfaces are on the opposite sides of a solid piece

of metal (usually used on lighter, less powerful vehicles)

Vented Rotor:

Has cooling passages cast between its friction surfaces allowing

cooling air to enter the center portion and exit at the outer edges

intended to provide lower operating temperature for better rotor and

lining life and improved fade resistance

Figure 4-2; solid and vented disc brake

2.1.9 FUNCTIONS OF DISC BRAKEThe main functional requirement for the brake system is "to provide a

controllable reduction of speed". The following function applies to

the brake rotor

Transmit braking power: The primary function is that the brake rotor

is ableto transmit power from the caliper to the rim.

Function

Transmit braking power Requirements

Withstand stress Ample space must be provided for steering, suspension, knuckle

assembly, stabilization and driveshaft Working temperature Recycling possible Design tolerances must coincide with other tolerances! Satisfy

test requirementsWithstand stress: It must be capable of withstanding the dynamic

stress and strain caused by retardation, steering and rough road.

Ample space must be provided: for the steering (front), the

suspensions, the stabilisers, the driveshafts, the caliper and the

knuckle assembly. The brake rotor has to be adapted to the dimensions

and tolerances that apply.

The rotor must satisfy the test requirements: for the retardation of

the vehicle (requirements from the authority), lifetime, and

reliability and safety requirements made by the car makers.

Working temperature: must be under the melting temperature for the

specified material.

Recycling possible: The material selected must be recyclable.

Design tolerances must coincide with the rest of the wheel parts.

Properties of the brake rotor Low noise level Low life cycle cost Low pollution rates Low energy consumption Low material consumption Provide safety & reliability

2.2.0 DAMAGE OF DISC BRAKE ROTOR DUE FRICTIONDamage to the friction surface usually is the result of extremes

in brake operation, extremes of wear, stress, temperature or

temperature variation. Various things can and will happen to the rotor

in the real world Extreme form of wear consisting of scratches, deep

grooves and a rough finish on the friction surface. Most common cause

is when linings have worn to the point where rivets, table or pad

backing plate contacts the drum or rotor.

Cracking:

Caused by stress of severe braking or an impact during a crash. Can appear anywhere on a rotor, usually at the edges of the

friction surface

Figure 4-2; crack formation of disc brake

Heat Checking Many small interlaced cracks on the friction surface. Typically

penetrate only a few thousandths of an inch and do not go into the

structure of the drum or rotor. Can cause rapid lining wear and slight

pedal noise.

Figure 4-2; heat checks on disc brake drum

2.2.1 MATERIAL PROPERTIES REQUIRED FOR DISC BRAKE 1. Provide homogenous friction coefficient

2. Low density

3. High corrosion resistance

4. High modulus of elasticity

5. High wear resistance

6. High heat conductivity

7. Low thermal expansion coefficient

8. High specific strength

2.2.2 MANUFACTURING PROCESS OF DISC BRAKE ROTAR

The most important PMMC material production parameters are:

particle incorporation (wetting), particle distribution, temperature

control and particle settling. The particles must be incorporated in

the melt so that no lumps occur and that the particle distribution

gets uniform. The wetting of the particles preserves a uniform

distribution. A uniform distribution also demands constant stirring of

the melt during holding and before pouring. This is particularly

important when the matrix contains small amounts of large Sic

particles when the settling rate is large. The chemical reaction

between the AlSi7Mg alloy matrix and the Sic particles limits the

feasible working temperature. The maximum processing and working

temperature of the composite is 800 °C.

During casting of products demanding uniform particle

distribution, it is important to be able to separate between the 4

different contributions to a non-uniform particle distribution:

settling, solidification rate, flow length and grain size, in order to

control the production process and reduce process variations. The

solidification conditions largely influence the particle distribution

in a casting, and the choice of casting method is dependent of this

relation. Short solidification time gives the best particle

distribution, and if uniform particle distribution is demanded the

choice of casting method is limited to permanent mould casting

processes. The settling rate is also dependent on the choice of

casting method, and, for instance, with high pressure die-casting ,the

particle settling during mould filling is almost negligible.

Figure 4-2; casting process

AFTER CASTING

Figure 4-2; casting process

CHAPTER-3

METHODOLOGY

3.1 STATEMENT OF PROBLEM

If looking on the overall automotive parts, besides engines,

there are more crucial parts that engineers need to look into

consideration. Suspension, brake, electrical, hydraulic and gear are

all the crucial systems in the automotive areas. Each of all system

has their own functionality which brings life to the automation

industries. Brakes is such a crucial system in stopping the vehicle on

all moving stages including braking during high speed, sharp

cornering, traffic jam and downhill. All of those braking moments give

a different value of temperature distribution and thermal stress. Good

performance of disc brake rotor comes from good material with better

mechanical and thermal properties. Good designs of disc brake rotor

are varying across the range of the vehicles. There are different

design and performance of disc brake rotor if compared between

passenger, commercial and heavy duty vehicle. There are also other

constraints such as cost, weight, manufacturing capability, robustness

and reliability, packaging, maintenance and servicing.

For example, heavy duty vehicle need large size of disc brake

rotor if compared to passenger vehicle. Due to that, it will increased

total weight of vehicle as well as fuel consumption and reduces

performances of the vehicle. Moreover, high weight of vehicle induces

to high temperature increased during braking where the higher value of

temperature during braking could lead to braking failure and cracking

of disc brake rotor.

This project concerns of the temperature distribution and

constraint of the disc brake rotor. Most of the passenger cars today

have disc brake rotors that are made of grey cast iron. Grey cast iron

is chosen for its relatively high thermal conductivity, high thermal

diffusivity and low cost. In this project, the author will investigate

on the thermal issues of normal passenger vehicle disc brake rotor,

where the investigation are to determine the temperature behavior of

the disc brake rotor due to severe braking of the disc brake rotor by

using Finite Element Analysis (FEA).

3.2 RESEARCH METHODOLOGY

Begin with a literature review, alot of paper and journal has

been read up and a part of it has been considered in this project.

Meanwhile, Coordinate Measuring Machine (CMM) has been used to measure

the major coordinate of real disc brake rotor. CMM has been used in

order to get accurate dimension of disc brake rotor. Later, the

precise dimensions have been used to translate in 2D and 3D drawing by

using CATIA.

In the second stage, load analysis has been done where the heat

flux and convectional heat transfer coefficients has been calculated.

Load analysis calculated based on full load of passenger in the normal

passenger vehicle. Later, value of load analysis has been applied on

finite element analysis.

Next, the fractional 3D model of disc brake rotor has been

transfer to finite element software which is ANSYS. Thermal analysis

has been done on steady state and transient responses. Assigning

material properties, load and meshing of the model has been done in

this stages. Then, completed meshing model has been submitted for

analysis. Finally an expected result from the steady state and

transient responses of thermal analysis has been obtained. A flow

chart below shows a better understanding of overall contents of this

project.

CHAPTER-4

MODELL

ING

4.1 MODELLING SOFTWARE There are different software’s available for modeling some of them

are:

1. Solid works

2. Pro-E

3. Ideas

4. Inventor

5. Mechanical desktop

6. Unigraphics

7. Catia v5

IN THIS PROJECT THE DESIGN IS DEVELOPED BY USING CATIA V5

SOFTWARE

4.1.1 INTRODUCTION TO CATIA V5

CATIA V5 provides the power of parametric design. With parametric, we

define the modal according to the size and positional relationship of

its parts.

PART MODELLING Many technical designs consist of complex assemblies made from

angular shaped parts. This type of design work can be made ashier by

part and assembly modeling capabilities that are well integrated. The

CATIA V5 is a 3-D parametric solid modeler with both part and assembly

modeling capabilities. You can see the CATIA V5 to model piece parts

and then combine them into more complex assemblies. With CATIA V5 a

part is designed by sketching its components shapes and defining their

size shape and inters relationships. By successfully creating these

features you construct the part in a building block fashion. Since

CATIA V5 has parametric features, you can change one feature and all

related features are automatically updated to reflect the change and

its effects throughout the part. It can be used to create angular

shaped part, to which 3D surface can be applied to create hybrid parts

consisting of mixture of angular and curved shapes.

CATIA V5 employs two operating modes for part modeling, model made

for modeling 3Dparametric parts and drawing mode for creating 2D drawings

of them. These modes operate independently but share the same design

data. Part modeling requires beginning the design work in model mode

where a model of the part is immediately built. Then the drawing mode can

be used at any point to document the design. In traditional CUMPUTER

AIDED DESIGN, a 2D drawing is created at the beginning and then 3D model

is built to analyze, and verify the initial concept.

4.1.2 DIMENSIONS OF DISC BREAK ROTAR

SOLID TYPE

Figure 4-2; solid disc dimensions

4.1.3 MODELLING OF SOLID DISC BRAKE USING CATIA V5

Figure 4-2; modeling of solid disc brake modelling

4.1.4 DIMENSIONS OF VENTEAD TYPE DISC BREAK

4.1.5 MODELLING OF VENTD DISC BREAK

4.1.6 INTRODUCTION OF FINITE ELEMENT ANALYSIS

The finite element method is numerical analysis technique for

obtaining approximate solutions to a wide variety of engineering

problems. Because of its diversity and flexibility as an analysis

tool, it is receiving much attention in almost every industry. In more

and more engineering situations today, we find that it is necessary to

obtain approximate solutions to problem rather than exact closed form

solution.

It is not possible to obtain analytical mathematical solutions

for many engineering problems. An analytical solutions is a

mathematical expression that gives the values of the desired unknown

quantity at any location in the body, as consequence it is valid for

infinite number of location in the body. For problems involving

complex material properties and boundary conditions, the engineer

resorts to numerical methods that provide approximate, but acceptable

solutions.

The finite element method has become a powerful tool for the

numerical solutions of a wide range of engineering problems. It has

been developed simultaneously with the increasing use of the high-

speed electronic digital computers and with the growing emphasis on

numerical methods for engineering analysis. This method started as a

generalization of the structural idea to some problems of elastic

continuum problem, started in terms of different equations

4.1.7 BRIEF INTRODUCTION OF ANASYS

4.18 PROCEDURE FOR ANSYS

Static analysis is used to determine the displacements stresses,

stains and forces in structures or components due to loads that do not

induce significant inertia and damping effects. Steady loading in

response conditions are assumed. The kinds of loading that can be

applied in a static analysis include externally applied forces and

pressures, steady state inertial forces such as gravity or rotational

velocity imposed (non-zero) displacements, temperaturesThe procedure for static analysis consists of these main steps

Building the mode

Obtaining the solution

Reviewing the results.

4.1.9 BUILD THE MODELIn this step we specify the job name and analysis title use PREP7

to define the element types, element real constants, material

properties and model geometry element type both linear and non- linear

structural elements are allowed. The ANSYS elements library contains

over 80 different element types. A unique number and prefix identify

each element type.

E.g. BEAM 94, PLAN 71, SOLID 96 and PIPE 16E

4.2.0MATERIAL PROPERTIES

Young’s modulus (EX) must be defined for a static analysis. If we plan

to apply inertia loads (such as gravity) we define mass properties

such as density (DENS). Similarly if we plan to apply thermal loads

(temperatures) we define coefficient of thermal expansion

S.NO MATERIAL PROPERTIES STAIN LESS STEEL GRAY CAST IRON1 Thermal conductivity, k(W/m_C) 36 57

2

Density (kg/m3) 710

0

7250

3

Specific heat, c (J/Kg. _C) 320 460

4

Poisson’s ratio 0.1

2

0.2

8

5

Thermal expansion 10 10-

85

6

Elastic modulus E 210 13

8

7

Coefficient of friction 0.5 0

.2

4.2.1 IMPORTING OF CATIA MODEL I N TO ANSYS

4.2.2 MESHING OF DISC BRAKE ROTAR

4.2.3 MESHAING DETAILS

DISC TYPE ELEMENTS NODES

SOLID DISC 35011 43733

VENTED DISC 14463 24832

4.2.4 SOLUTION

In this step we define the analysis type and options, apply loads

and initiate the finite element solution. This involves three phases:

Pre-processor phase

Solution phase

Post-processor phase

CHAPTER-5

5.1.1 RESULTS AND DISCUSSION

5.1.2 STAIN LESS STEEL SOLID DISC RESULTS

Figure 4-1: Deformation in stainless steel

Figure 4-2; displacement sum in stain less steel

Figure 4-2; von misses stress stain less steel

5.1.3 STAIN LESS STEEL VENTED DISC RESULTS

Figure 4-2: Deformation in stainless steel

Figure 4-2; displacement sum in stain less steel

Figure 4-2; von misses stress stain less steel

5.1.4 GRAY CAST IRON SOLID DISC RESULTS

Figure 4-3: Deformation in gray cast iron

Figure 4-2; displacement sum in gray cast iron

Figure 4-2 von misses in gray cast iron

5.1.5 GRAY CAST IRON VENTED DISC RESULTS

Figure 4-2 deformation in gray cast iron

Figure 4-2; displacement sum in gray cast iron

Figure 4-2; von misses in gray cast iron

5.1.6 Table of Result Analysis (Gray Cast Iron)

s.no Parameters Solid type Ventilated

type

1 Deformation 0.01833 0.01740

2 Displacement 0.00561 0.00488

3 Von misses stress 0.01833 0.01740

5.1.7 Table of Result Analysis (stain less steel)

s.no Parameters Solid type Ventilated

type

1 Deformation 0.02142 0.019606

2 Displacement 0.02107 0.017400

3 Von misses stress 0.021426 0.017405

6 CONCLUSION

Total Deflection (in mm.) is less in vented type disc brake and

best suited material is Grey Cast Iron.

Von-mises stases (in MPa) are very less in Grey Cast Iron, so

best suited material is Grey Cast Iron.

Total displacement is less in ventilated disc and best suited

material is Gray cast iron

It is observed that the vented type disk brakes can provide

better heat dissipation than the solid ones; present study can be

provide a useful design tools and improvement of the brake

performance in disk brake system. We can say that from all the

values obtained from the analysis i.e. the Total Deformation, Von

misses Stress exhibit that the vented disc is best suited design.

Comparing the different results obtained from analysis, it is

concluded that disk brake with vents and of material Grey Cast Iron

is observed best possible combination for present application

7 FUTURE SCOPE

The automobile industry has shown greater interest in the use of

ventilated gray cat iron disc brake rotors in the place of solid disc

brake rotors due to its high strength and heat dissipation.

Gray cast iron materials are light, strong and are being used in

a wide variety of products. Gray cast iron material give better heat

dispassion and less deformation compare with stain less steel

So the gray cast iron disc brake rotors have a bright future in

automobiles. In the present days high standard cars are using these

ventilated disc brake rotors because of its high strength to weight

ratio. In future when its usage becomes feasible gray cast iron disc

brake rotors will play an important role in automobiles because of its

best features.

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