project

Coupled Field Finite Element Analysis of Car Disc Brake Rotors

Dept. of Mechanical Engineering SDMCET, Dharwad 1

TABLE OF CONTENTS

Chapters Page No.

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER 1: INTRODUCTION 06

1.1 Fundamentals of Braking System

1.1.1 Principle of braking. 07

1.1.2 Coefficient of friction 08

1.2 Braking systems.

1.2.1 Brake types in cars.

1.2.1.1 Drum Brake. 08

1.2.1.2 Disc Brake. 08

1.2.1.3 Antilock Braking System (ABS) 08

1.2.2 Air brakes. 09

1.2.3 Exhaust brakes. 09

1.2.4 Electric brakes. 09

1.2.5 Parking brakes. 10

1.3 Braking system components.

1.3.1 Brake pedal. 10

1.3.2 Brake lines. 10



1.3.3 Brakes fluid. 10

1.3.4 Master cylinder. 11

1.3.5 Divided systems. 11

1.3.6 Tandem master cylinder. 12

1.3.7 Power booster or brake unit. 12

1.3.8 Hydraulic brake booster. 12

1.3.9 Electrohydraulic braking (EHB). 12

1.4 Disc brake systems.

1.4.1 Disc brake operation. 13

1.4.2 The rotor. 15

1.4.2.1 Brake fade 16

1.4.2.2 Rotor Metallurgy 16

1.4.2.3 Rotor Surface finish 17

1.4.3 Disc brake pads. 17

1.4.4 Disc brake calipers. 18

CHAPTER 2: LITERATURE REVIEW 19

CHAPTER 3: MATERIAL PROPERTIES OF DISC BRAKE

ROTORS 25

3.1 Materials used 25



3.2 Cast Iron 25

3.3 Specifications of car and Material Properties of Gray cast iron

3.3.1 Solid disc brake rotor

3.3.1.1 The specifications of car 26

3.3.1.2 The materials properties 26

3.3.2 Ventilated disc brake rotor

3.3.2.1 The specifications of car 27

3.3.2.2 The materials properties 27

CHAPTER 4: THEORY AND CALCULATIONS

4.1 Assumptions. 29

4.2 Stopping distance. 29

4.3 Weight transfer. 30

4.4 Braking efficiency. 31

4.5 Kinetic energy and Heat flux.

4.5.1 Approaches 32

4.5.2 Macroscopic model approach 32

4.6 Calculations

4.6.1 Calculations for heat flux application time 33

4.6.2 Calculations for kinetic energy heat flux time

4.6.2.1 Solid disc brake rotor 33



4.6.2.2 Ventilated disc brake rotor 35

CHAPTER 5: GEOMETRIC MODELING

5.1 Pro e Wildfire 4. 37

5.2 Module 2 - Part Modeling. 37

5.3 Module 5 - Drawing. 38

5.4 Modeled and drafted components. 38

CHAPTER 6: FINITE ELEMENT MODELING 41

6.1 Meshed components 42

6.2 SOLID90 43

6.2.1 SOLID90 Element Description 43

6.2.2 SOLID90 Input Data 44

6.2.3 SOLID90 Input Summary 44

6.2.4 SOLID90 Output Data 45

6.2.5 SOLID90 Assumptions and Restrictions 45

CHAPTER 7: FINITE ELEMENT ANALYSIS

7.1 Introduction. 47

7.2 Steps in FEA.

7.2.1 General Steps. 47

7.2.2 Steps in ANSYS. 47



7.3 Coupled field analysis. 48

7.3.1 Thermal Structural Analysis 49

7.3.2 Thermal and Structural Boundary Conditions 49

7.4 Modal analysis. 50

7.5 Procedure adopted for thermal analysis

of disc brake rotors. 50

7.6 Procedure adopted for structural analysis


7.7 Procedure adopted for modal analysis


CHAPTER 8: RESULTS

8.1 Inputs and results of ANSYS 11 52

8.2 Plots of Results

8.2.1 Solid disc brake rotor 53

8.2.2 Ventilated disc brake rotor 61

CHAPTER 9: CONCLUSION 69

CHAPTER 10: FUTURE SCOPE 70

REFERENCES



CHAPTER 1

INTRODUCTION

At the end of the 19th century the development of a brake system for the newly

invented automobile vehicles was needed. From that moment on, brake system which

makes use of several components (the brake disc among them), was developed. It was

after the beginning of the Second World War, in 1938, that the brake system

technological advance got great impulse due to the aeronautics industry necessity. Around

1886, in Germany, Gotlieb Daimler and Carl Benz would change the history of the world

forever, because they created, independently, the first prototypes of internal combustion

automobiles. This invention gave rise to the development of several automobile

components, and among them was the brake system. In the United States, in 1890,

according to Hughes, the American Elmer Ambrose Sperry invented a brake similar to the

present disc brake. An automotive brake disc brake rotor is a device for slowing or

stopping the motion of a wheel while it runs at a certain speed. In this project work the

complete study of brake systems used in cars is studied and the actual dimensions of the

solid and ventilated disc brake rotors of TATA indica cars are taken which are used to 3D

modeling of rotors in Pro e Wildfire 4. The model is then converted to iges format and

imported to Altair Hypermesh 7 for meshing. After meshing it is imported to ANSYS 11

with element for meshing defining as SOLID 90. Here coupled field finite element

analysis and modal analysis is carried using general purpose finite element analysis. Then

the results are compared for both solid and ventilated disc brake rotors and alternate

materials are also suggested.

The goals of our project are as follows:

i. Complete study of braking system in car.

ii. Conceptualization of working of the disc rotor.

iii. To carry out coupled-field analysis i.e., thermal to static structural analysis which

gives thermal stresses and their corresponding displacements in the disc brake

rotor due to the application of temperature.



iv. To predict natural frequencies and associated mode shapes by considering density

of the disc material.

v. Comparison of solid and ventilated rotor based on the above results.

vi. Suggesting the suitable material for disc brake rotor and checking whether the

design is safe or not based on the above results.

1.1 Fundamentals of Braking system

1.1.1 Principle of braking:

A basic braking system of a car has:

Brake pedal.

Master cylinder to provide hydraulic pressure.

Brake lines and hoses to connect the master cylinder to the brake assemblies.

Fluid to transmit force from the master cylinder to the wheel cylinders of the

brake assemblies, and

Brake assemblies drum or disc that stop the wheels.

The driver pushes the brake pedal; it applies mechanical force to the piston in the

master cylinder. The piston applies hydraulic pressure to the fluid in the cylinder, the

lines transfer the pressure which is undiminished in all directions within the brake lines

to the wheel cylinders, and the wheel cylinders at the wheel assemblies apply the brakes.

Force is transmitted through the fluid. For cylinders of the same size, the force

transmitted from one is the same value as the force applied to the other. By using

cylinders of different sizes, forces can be increased or reduced. In an actual braking

system, the master cylinder is smaller than the wheel cylinders, so the force at all of the

wheel cylinders is increased. When brakes are applied to a moving vehicle, they absorb

the vehicles kinetic energy. Friction between the braking surfaces converts this energy

into heat. In drum brakes, the wheel cylinders force brake linings against the inside of the

brake drum. In disc brakes, pads are forced against a brake disc. In both systems, heat

spreads into other parts and the atmosphere, so brake linings and drums, pads and discs

must withstand high temperatures and high pressures.



1.1.2 Coefficient of friction

Friction is a force that resists the movement of one surface over another. It can be

desirable but often is not. It's caused by surface rough spots that lock together. These

spots can be microscopically small, which is why even surfaces that seem to be smooth

can experience friction. Friction can be reduced but never eliminated. Friction is always

measured for pairs of surfaces, using what is called a coefficient of friction. A low

coefficient of friction for a pair of surfaces means they can move easily over each other.

A high coefficient of friction for a pair of surfaces means they cannot move easily over

each other.

1.2 Braking Systems

1.2.1 Brake types in cars

1.2.1.1 Drum Brake

Drum brakes have a drum attached to the wheel hub, and braking occurs by means

of brake shoes, expanding against the inside of the drum. A drum brake is a brake in

which the friction is caused by a set of shoes or pads that press against the inner surface

of a rotating drum. The drum is connected to a rotating wheel.

1.2.1.2 Disc Brake

With disc brakes, a disc attached to the wheel hub maybe clamped between 2

brake pads. On light vehicles, both of these systems are hydraulically operated. The brake

pedal operates a master cylinder. Disc brakes require greater forces to operate them. A

brake booster assists the driver by increasing the force applied to the master cylinder,

when the brake is operated.

1.2.1.3 Antilock Braking System (ABS)

An anti-lock braking system (commonly known as ABS, from the German name

"Antiblockiersystem" given to it by its inventors at Bosch) is a system on motor vehicles

which prevents the wheels from locking while braking. The purpose of this is to allow the



driver to maintain steering control and to shorten braking distances. It is composed of a

central electronic unit, four speed sensors (one for each wheel) and two or more hydraulic

valves on the brake circuit.

1.2.2 Air Brakes

Air-operated braking systems are used on heavy vehicles. Compressed air,

operating on large-diameter diaphragms, provides the large forces at the brake assembly

that are needed. An air compressor pumps air to storage tanks. Driver-controlled valves

then direct the compressed air to different wheel units, to operate the friction brakes.

1.2.3 Exhaust Brakes

Heavy goods vehicles can often require increased braking, in situations where

friction brakes could overheat and fail. This is achieved by using an exhaust brake. An

exhaust brake works by restricting the flow of exhaust gases through the engine. It

achieves this by closing a butterfly valve located in the exhaust manifold. This maintains

high pressure in the exhaust manifold and the engine cylinders, which in turn acts as a

brake against the engine rotating. This then slows the road wheels through the

transmission, or power train. Other heavy goods vehicles use an engine brake that

operates by altering valve timing, and stopping fuel being injected into the engine.

1.2.4 Electric Brakes

An electric braking system is commonly used to activate the drum-type friction

brakes on the trailer. Braking effect can be increased or reduced by the driver, adjusting a

control unit to suit the load on the trailer. When the brakes in the towing vehicle are

applied, the brake-light circuit sends the signal to the control unit. The control unit then

sends an appropriate current to the trailer brake actuators, to operate the trailer brakes, at

the level selected.



1.2.5 Parking Brakes

All vehicles must be fitted with a foot brake and a park brake. Most light vehicles

use a foot brake that operates through a hydraulic system on all wheels, and a hand-

operated brake that acts mechanically on the rear wheels only. The hand brake system

holds the vehicle when it is parked. Some vehicles incorporate a drum brake for the hand

brake, in the center of the rear disc brake. Others use a mechanical linkage to operate the

disc brake from the hand brake system, or separate hand brake calipers with their own

pads. Some vehicles have the hand brake operating on the front wheels. Some vehicles

use a single drum brake on the rear of the gearbox as a hand brake. That's sometimes

called a transmission brake.

1.3. Braking system components

1.3.1 Brake Pedal

The brake pedal uses leverage to transfer the effort from the drivers foot to the

master cylinder. Different lever designs can alter the effort the driver needs to make, by

using different levels of mechanical advantage.

1.3.2 Brake lines

Brake lines carry brake fluid from the master cylinder to the brakes.

They are basically the same on all brake systems. For most of their length they are steel,

coated to reduce the possibility of corrosion, and attached to the body with clips or

brackets to prevent damage from vibration. In some vehicles, the brake lines are inside

the vehicle to protect them better from corrosion.

1.3.3 Brake fluid

Brake fluid is hydraulic fluid that has specific properties. The fluid is used to

transfer force while under pressure through hydraulic lines to the wheel braking system.

The properties of different types of brake fluids are tested for many different



characteristics such as ph value, viscosity, resistance to oxidation and graded against

compliance standards set by United States Department of Transportation (DOT).

Brake fluid DOT specifications:

DOT 2 is castor oil based

DOT 3 is composed of various glycol esters and ethers.

o Boiling point: 284 F (140 C)

DOT 4 is also composed of glycol esters and ethers.


DOT 5 is silicone-based. It is NOT recommended for any vehicle equipped with

antilock brakes (ABS). It gives better protection against corrosion, and is more

suitable for use in wet driving conditions.


DOT 5.1 is a high-boiling point fluid that is suitable for ABS-equipped vehicles. It

contains polyalkylene glycol ether, but is more expensive than other brake fluids.

o Boiling point: 375 F (190.6 C)

Even if they have similar base composition, fluids with different DOT ratings must not be

mixed.

1.3.4 Master cylinder

The master cylinder is connected to the brake pedal via a pushrod. This is a single

master cylinder for a drum brake system. Its one piston has a primary and a secondary

cup. These are also known as seals, because, when force is applied to the brake pedal, the

primary cup seals the pressure in the cylinder. The secondary cup prevents loss of fluid

past the end of the piston. An outlet port links the cylinder to the brake lines.

1.3.5 Divided systems

Modern cars use tandem master cylinders to suit divided or dual line braking

systems. A divided system is safer in the event of partial failure. Fluid loss in one half of



the system still leaves the other half able to stop the vehicle, although with an increase in

stopping distance.

1.3.6 Tandem master cylinder

With a basic master cylinder in the braking system, any loss of fluid, say because

a component fails, could mean the whole braking system fails. To reduce this risk,

modern vehicles must have at least two separate hydraulic systems. Thats why the

tandem master cylinder was introduced.

1.3.7 Power booster or Brake unit

A power booster or power brake unit uses a vacuum to multiply the drivers pedal

effort and apply that to the master cylinder. This increases the pressures available from

the master cylinder. Units on petrol/gasoline engines use the vacuum produced in the

intake manifold. Vehicles with diesel engines cannot use manifold vacuum so they are

fitted with an engine-driven vacuum pump. The most common booster operates between

the brake and master cylinder.

1.3.8 Hydraulic brake booster

Although not as common as a conventional brake system fitted with a vacuum

booster, many vehicles are now equipped with hydraulically assisted boosters for the

brakes. The system uses hydraulic pressure generated by the power steering pump rather

than engine vacuum to provide the power assistance required in a conventional system.

This application is particularly suitable to vehicles with diesel engines as a separate

vacuum source does not have to be provided for the system to operate.

1.3.9 Electrohydraulic braking (EHB)

Electrohydraulic Braking (EHB) gets rid of the vacuum booster and replaces the

current modulator with one that includes a high pressure accumulator. Like the Hydro

boost system it uses an accumulator to provide the required pressure to activate the master

cylinder, however, it uses electrical power to effectively charge the accumulator and



build sufficient pressure for efficient brake operation. This system means that less power

is taken away from the engine during operation as battery power is used.

1.4 Disc brake system

The primary components of disc brakes are: the rotor, caliper and brake pads.

Fig 1.1 Disk brake system

1.4.1 Disc brake operation

Disc brakes can be used on all four wheels of a vehicle, or combined with disc

brakes on the front wheels and drum brakes on the rear. When the brake pedal is

depressed, a push rod transfers the force through a brake booster to a hydraulic master

cylinder. The master cylinder converts the force into hydraulic pressure, which is then



transmitted via connecting pipes and hoses to one or more pistons at each brake caliper.

The pistons operate on friction pads to provide a clamping force on a rotating flat disc

that is attached to the wheel hub. This clamping tries to stop the rotation of the disc, and

the wheel. On non-driving wheels, the center of the brake disc or hub contains the wheel

bearings. The hub can be part of the brake disc or a separate assembly between the wheel

and hub with nuts or bolts. On driving wheels, the disc is mounted onto the driving axle

and may be held in place by the wheel. On front wheel drive vehicles, it can be mounted

on the front hub and wheel bearing assembly. The brake caliper assembly is bolted to the

vehicle axle housing or suspension. In most cases the brake is positioned as close as

possible to the wheel, but there are exceptions. Some high-performance cars use inboard

disc brakes on its rear wheels. The makers claim improved vehicle handling for this

design because it reduces unsprung weight. Applying brakes can absorb a lot of vehicle

energy so friction between braking surfaces generates great heat. Brake parts withstand

very high temperatures. Most of the friction area of a disc is exposed to air so cooling is

far more rapid than for a drum brake. Unlike with drum brakes, brake fade is rare.

Because of their shape, discs tend to throw off water. So after being driven through water,

they operate almost immediately. Disc brakes need much higher pressures to operate than

drum brakes, so almost all disc brake systems need a power brake booster to help reduce

the pedal forces that are needed from the driver.

Fig 1.2 Schematic diagram of disc brake operation



1.4.2 The rotor

The rotor is the main rotating part of this brake system. It is hard wearing and

resists the high temperatures that occur during braking. Rotors can be of a solid

construction or slotted. The slotted rotor is referred to as a "ventilated disc". Brake rotors

provide a friction surface for the disc brake pads to rub against when the brakes are

applied. The friction created by the pads rubbing against the rotor generates heat and

brings the vehicle to a stop. The underlying scientific principle here is that friction

converts motion into lot of heat and this heat is to be dissipated. The amount of heat that

is generated depends on the speed and weight of the vehicle, and how hard the brakes are

applied.

Fig 1.3 Schematic diagram of Solid and Ventilated disc brake rotor

The rotor's job is to provide a friction surface, and to absorb and dissipate heat.

Big rotors can obviously handle more heat than small rotors. But many cars today have

downsized rotors to reduce weight. Consequently, the brakes run hotter and require better

rotor cooling to keep brake temperatures within safe limits. Uneven rotor wear often

produces variations in thickness that can be felt as pedal pulsations when the brakes are

applied. The condition usually worsens as the rotors continue to wear, eventually



requiring the rotors to be resurfaced or replaced. Rotors can also develop hard spots that

contribute to pedal pulsations and variations in thickness. Hard spots may be the result of

poor quality castings or from excessive heat that causes changes in the metallurgy of the

rotors. A sticky caliper or dragging brake may make the rotor run hot and increase the

risk of hard spots forming. Hard spots can often be seen as discolored patches on the face

of the rotor. Resurfacing the rotor is only a temporary fix because the hard spot usually

extends well below the surface and usually returns as a pedal pulsation within a few

thousand miles. Cracks can form as a result of poor metallurgy in the rotor and from

excessive heat. Some minor surface cracking is tolerable and can often be removed by

resurfacing, but large cracks or deep cracks weaken the rotor and increase the risk of

catastrophic failure

1.4.2.1 Brake fade: When brake temperatures get too high, the pads and rotors are no

longer able to absorb any more heat and lose their ability to create any additional friction.

As the driver presses harder and harder on the brake fade, he feels less and less response

from his overheated brakes. Eventually, he loses his brakes altogether. All brakes will

fade beyond a certain temperature. Semi-metallic linings can usually take more heat than

nonasbestos organic or low-met linings. Vented rotors can dissipate heat more rapidly

than nonvented solid rotors. Thus, high performance cars and heavier vehicles often have

vented rotors and semi-metallic front brake pads to handle high brake temperatures. But if

the brakes get hot enough, even the best ones will fade.

1.4.2.2 Rotor metallurgy: The metallurgical properties of a rotor determine its

strength, noise, wear and braking characteristics. The casting process must be carefully

controlled to produce a high quality rotor. The rate at which the iron cools in the mold

must be closely monitored to achieve the correct tensile strength, hardness and

microstructure. When iron cools, the carbon atoms that are mixed in with it form small

flakes of graphite which help dampen and quiet noise. If the iron cools too quickly, the

particles of graphite do not have as much time to form and are much smaller in size,

which makes for a noisy rotor. The rate of cooling also affects the hardness of a rotor. If a

rotor is too hard, it will increase pad wear and noise. Hard rotors are also more likely to

crack from thermal stress. If a rotor is too soft, it will wear too quickly and may wear



unevenly increasing the risk of pedal pulsation and runout problems. The composition of

the iron must also be closely controlled during the casting process to keep out impurities

that may form "inclusions" and hard spots.

1.4.2.3 Rotor surface finish: Smoother is always better because it affects the

coefficient of friction, noise, pad seating, pad break-in and wear. As a rule, most new

OEM (Original Equipment Manufacturer) and quality aftermarket rotors have a finish

somewhere between 30 and 60 inches RA (roughness average) with many falling in the

40 to 50 RA range. As a general rule, there should be no more than .003 inches of rotor

runout on most cars and trucks, but some cars cannot tolerate any more than .0015 inches

of runout.

1.4.3 Disc brake pads

A disc brake pad has a rigid, molded, friction material bonded to a steel backing

plate for support during brake application. It transforms the hydraulic force of the caliper

into a frictional force against the disc. Disc brake pads consist of friction material bonded

onto a steel backing plate. The backing plate has lugs that locate the pad in the correct

position in relation to the disc. Calipers are usually designed so that the condition of the

pads can be checked easily once the wheel has been removed, and to allow the pads to be

replaced with a minimum of disassembly. Some pads have a groove cut into the friction

surface. The depth of this groove is set so that when it can no longer be seen, the pad

should be replaced. Some pads have a wire in the friction material at the minimum wear

thickness. When the pad wears to this minimum thickness, the wire touches the disc as

the brakes are applied. A warning light then tells the driver the disc pads are due for

replacement. The composition of the friction material affects brake operation. Materials

which provide good braking with low pedal pressures tend to lose efficiency when they

get hot. This means the stopping distance will be increased. Materials which maintain a

stable friction co-efficient over a wide temperature range generally require higher pedal

pressures to provide efficient braking. Disc rotors with holes or slots in them dissipate

their heat faster, and also help to remove water from the surface of the pad in wet driving

conditions. They also help to prevent the surface of the pad from becoming hard and



glassy smooth from the friction and heat of use. However, this scraping action reduces the

overall life of the brake pad, so these types of discs are generally only used in high

performance or racing cars.

1.4.4 Disc brake calipers

The disc brake caliper assembly is bolted to the vehicle axle housing or suspension.

There are 2 main types:

fixed

sliding.

Fixed calipers can have 2, 3, or 4 pistons. 2-piston calipers have one piston on each

side of the disc. Each piston has its own disc pad. When the brakes are applied, hydraulic

pressure forces both pistons inwards, causing the pads to come in contact with the

rotating disc. The sliding or floating caliper has 2 pads but only 1 piston. The caliper is

mounted on pins or bushes that let it move from side to side. When the brakes are

applied, hydraulic pressure forces the piston inwards. This pushes the pad against the

disc. The caliper is free to move on slides, so there is a clamping effect between the inner

and outer pads. Equal force is then applied to both pads which clamp against the disc. In

disc brake calipers, the piston moves against a stationary square section sealing ring.

When the brakes are applied, the piston slightly deforms the seal. When the brakes are

released, the seal returns to its original shape. The action of this sealing ring retracts the

piston to provide a small running clearance between the disc and pads. It also makes the

brake self-adjusting.



CHAPTER 2

LITERATURE REVIEEW

In order to carry out the project the following literature available are studied and

understood to the extent possible to make correct decisions, assumptions and calculations

to obtain the optimum results.

Catalin Spulber and Stefan Voloaca [1]: This paper proposes a new simulation method

of a disc brake thermal stress resistance, for different temperatures, by interactive

processing of images obtained by thermography. Temperature evaluation for different

working regimes can be made by recording and processing thermograms of a disc brake

heated inside the laboratory by an external heating source. Taken pictures along the

temperature variation, from the ambient value to a value close to real one obtained on the

usual experiments, are processed using image analyse softwares. This way can be

simulated different working regimes (temperature, humidity etc.) without the need of

experimental determination on the road or on a test bench.

V.M.M.Thilak, R.Krishnaraj, Dr.M.Sakthivel, K.Kanthavel, Deepan Marudachalam

and M.G, R.Palani [2]: Transient Thermal and Structural Analysis of the Rotor Disc of

Disc Brake is aimed at evaluating the performance of disc brake rotor of a car under

severe braking conditions and there by assist in disc rotor design and analysis. An

investigation into usage of new materials is required which improve braking efficiency

and provide greater stability to vehicle. This investigation can be done using ANSYS

software. ANSYS 11.0 is a dedicated finite element package used for determining the

temperature distribution, variation of the stresses and deformation across the disc brake

profile. In the present work, an attempt has been made to investigate the suitable hybrid

composite material which is lighter than cast iron and has good Youngs modulus, Yield

strength and density properties. Aluminum base metal matrix composite and High

Strength Glass Fiber composites have a promising friction and wear behavior as a Disc

brake rotor. The transient thermo elastic analysis of Disc brakes in repeated brake

applications has been performed and the results were compared. The suitable material for



the braking operation is S2 glass fiber and all the values obtained from the analysis are

less than their allowable values. Hence the brake Disc design is safe based on the strength

and rigidity criteria. By identifying the true design features, the extended service life and

long term stability is assured.

Rajendra Pohane and R.G.Choudhari [3]: Repetitive braking of the vehicle leads to

heat generation during each braking event. The resulting rise in temperatures has very

significant role in the performance of the braking system. Passenger car disc brakes are

safety critical component whose performance depends strongly on contact conditions at

the pad to disc interface. During braking both brake pad & disc surface is worn. The

objective of the paper is to study disc brake system, to simulate disc brake assembly and

to prepare the FEM model for contact analysis. A three dimensional finite element model

of the brake pad and the disc is developed to calculate static structural analysis, and

transient state analysis. The comparison is made between the solid and ventilated disc

keeping the same material properties and constraints and using general purpose finite

element analysis. This paper discusses how general purpose finite element analysis

software can be used to analyze the equivalent (von-mises) stresses& the thermal stresses

at disc to pad interface.

H.Mazidi, S.Jalaifar and J. Chakhoo [4]: In this study the heat conduction problems of

the disc brake components (pad and rotor) are modeled mathematically and is solved

numerically using Finite Difference Method. In the discretization of time dependent

equations the implicit method is taken into account. In the derivation of the heat

equations, parameters such as the duration of braking, vehicle velocity geometries and the

dimensions of the brake components, material of the disc brake rotor and the pad and

contact pressure distribution have been taken into account. Results show that there is a

heat partition at the contact surface of two sliding components, because of thermal

resistance due to the accumulation of wear particles between contact surfaces. This

phenomenon prevents absorption of more heat by the discs and causes brake lining to be

hot. As a result, heat soaking to the brake fluid increases and may cause brake fluid to

evaporate.

project

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