PRESENTATION OUTLINE

PRESENTATION OUTLINEPRESENTATION OUTLINE

1.0 Introduction

2.0 Literature Review

3.0 Simple Disc Brake Model

4.0 Research Methodology

5.0 Thermal Analysis Results

6.0 Overview of PSM 2

INTRODUCTIONINTRODUCTION

Disc brake generally consists of 3 components:

i) Disc rotor

ii) Brake pads

iii) Caliper

Braking system plays 3 major roles:

i) Decelerate vehicle including stopping

ii) Maintain vehicle speed during downhill operation

iii) Hold a vehicle stationary on a grade

Kinetic energy lost at wheels converted to heat through friction

Kinetic energy increase with the square of vehicle velocity

E = ½ mv2

where: E = kinetic energy generated

m = vehicle mass

v = vehicle velocity

~95% of heat generated are absorbed by brake components

High temperature at disc brake components may cause undesirable effects, leading to brake failure

STATEMENT OF PROBLEMSTATEMENT OF PROBLEM

RESEARCH OBJECTIVERESEARCH OBJECTIVE

To determine temperature distribution at friction pad surfaces

SCOPE OF RESEARCHSCOPE OF RESEARCH

Perform initial thermal analysis on a simple disc brake model

Perform thermal analysis on real disc brake assembly model

Determine temperature distribution at friction pad surfaces

Perform sensitivity studies of temperature distributions related to:

Disc angular speed, ω

Brake line pressure, P

Friction coefficient, μ

PSM 1 PLANNING CHARTPSM 1 PLANNING CHART

LITERATURE LITERATURE REVIEWREVIEW

SIGNIFICANCE OF THERMAL ANALYSISSIGNIFICANCE OF THERMAL ANALYSIS

High temperature at disc brake components may cause undesirable effects, leading to brake failure

Examples of thermal effects:

Brake fade phenomenon

Local scoring

Premature wear

Bearing failure

Thermal cracks

Brake fluid vaporization

Thermally excited vibration

Thermo elastic instability

thermal crack

new disc (left) & warped disc (right)

Hot spots due to thermo-elastic instability (TEI)

Importance of performing thermal analysis at early stage :

- to allow modifications on disc brake design and materials

- ensure proper functioning during operation

- shorten product development cycle time

EXAMPLES OF THERMAL ANALYSISEXAMPLES OF THERMAL ANALYSIS

Experimental ApproachExperimental Approach

Fast Non-Contact Temperature Measurement

Use optical fibres and fast photon infradetectors

Temperature determined by output signal intensity of detectors

Data recorded via software and presented graphically

Infrared Thermography

Requires high speed infrared camera and roller bench

Advantages:

Able to capture temperature distribution at rotating wheels

Visualization of whole thermal field

Drawback : requires proper view of the disc brake from wheels (not blocked by wheel rims)

Finite Element ApproachFinite Element Approach

Thermal Analysis using ABAQUS v6.4

Observe temperature distribution on disc and pad surfaces

Consist of a disc rotor and single brake pad

Brake pad pressed against disc for 0.01sec, disc rotor rotates at 60°for 0.015 sec

3-dimensional disc brake model

Temperature distribution at disc surface Temperature distribution at pad surface

Thermal Analysis by ThermoAnalytics Inc.

(RadTherm)

Real brake model of Ford Mustang

Vented disc (48 vents)

To observe temperature distribution at hub and disc rotor only

Analysis method using repeated braking cycle

meshed disc brake model

Graphical results after 8.9 minutes

COMPONENTS

Disc Rotor

Upper Friction Pad

Lower Friction Pad

SIMPLE DISC BRAKE MODELSIMPLE DISC BRAKE MODEL

Developed and analyzed using ABAQUS v6.4

Consist of 3 components i.e. disc rotor, upper friction pad & lower friction pad

Thermal analysis to observe temperature distribution on friction pad surface

modeling of disc brake model

applying load & boundary condition

meshing of disc brake model

638 C3D8T elements - 8-node linear hexahedron thermally coupled brick with trilinear displacement and temperature

3861 Degree of Freedoms (DOFs)

RESEARCH METHODOLOGYRESEARCH METHODOLOGY

FLOW CHARTFLOW CHART

THERMAL ANALYSIS RESULTSTHERMAL ANALYSIS RESULTS

BASE LINE CONDITION

SENSITIVITY STUDIES

THERMAL ANALYSIS AT BASE LINE THERMAL ANALYSIS AT BASE LINE CONDITIONCONDITION

Three parameters are fixed (constant):

Disc angular speed, ω = 92.6 rad/s

Brake line pressure, P = 1.41 MPa

Friction coefficient, μ= 0.35

Temperature Distribution Temperature Distribution Contour PlotsContour Plots

upper friction pad

lower friction pad

t = 0.0 seconds

t = 1.0 seconds

t = 2.0 seconds

Temperature Distribution Temperature Distribution Along Friction PadsAlong Friction Pads

Results shown by taking 3 specific

paths on friction pad :

Leading edgeCenter Trailing edge

0 5 10 15 20 25 30 35 40

Distance (mm)

Upper PadLower Pad

0 5 10 15 20 25 30 35 40Distance (mm)

Upper pad leadingUpper pad trailingLower pad leadingLower pad trailing

temperature distribution along center of friction pads

temperature distribution along leading and trailing edges

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (seconds)

Upper pad leadingUpper pad trailingLower pad leadingLower pad trailing

temperature increment for leading and trailing edges

SENSITIVITY STUDIESSENSITIVITY STUDIES

To observe effect of varied

parameters on temperature

distribution at friction pad surfaces

Varied parameters with increment

of 20% from base line value

PARAMETERS BASE LINE CONDITION VARIED CONDITION

Disc angular speed, ω(rad/s)

92.6 111.12

Brake line pressure, P (MPa)

1.41 1.83

Friction coefficient, μ 0.35 0.42

Disc Angular Speed = 111.12 rad/sDisc Angular Speed = 111.12 rad/s

upper friction pad lower friction pad

*top of diagram is leading edge

0 5 10 15 20 25 30 35 40

Distance (mm)

Upper Pad Initial

Lower Pad Initial

Upper Pad (ω = 111.12 rad/s)

Lower Pad (ω = 111.12 rad/s)

0 5 10 15 20 25 30 35 40Distance (mm)

Upper pad leadingLower pad leadingUpper pad leading (ω = 111.12 rad/s) Lower pad leading (ω = 111.12 rad/s)

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (seconds)

Upper pad leadingLower pad leadingUpper pad leading (ω = 111.12 rad/s)Lower pad leading (ω = 111.12 rad/s)

temperature distribution along center of friction pads temperature distribution along leading edges

temperature increment at leading edges of friction pads

Brake Line Pressure = 1.83 MPaBrake Line Pressure = 1.83 MPa

0 5 10 15 20 25 30 35 40Distance (mm)

Upper Pad Initial

Lower Pad Initial

Upper Pad (P = 1.83 MPa)

Lower Pad (P = 1.83 MPa)

0 5 10 15 20 25 30 35 40Distance (mm)

Upper pad leadingLower pad leadingUpper pad leading (P = 1.83 MPa) Lower pad leading (P = 1.83 MPa)

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (seconds)

Upper pad leadingLower pad leadingUpper pad leading (P = 1.83 MPa)Lower pad leading (P = 1.83 MPa)

Friction Coefficient = 0.42Friction Coefficient = 0.42

0 5 10 15 20 25 30 35 40

Distance (mm)

Upper Pad Initial

Lower Pad Initial

Upper Pad (μ = 0.42)

Lower Pad (μ = 0.42)

0 5 10 15 20 25 30 35 40Distance (mm)

Upper pad leadingLower pad leadingUpper pad leading (μ = 0.42) Lower pad leading (μ = 0.42)

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (seconds)

Upper pad leadingLower pad leadingUpper pad leading (μ = 0.42)Lower pad leading (μ = 0.42)

PARAMETERS UPPER FRICTION PAD LOWER FRICTION PAD

Maximum temperature (°C) 312.8 355.7

Simulation time (s) 2 2

Base line condition:ω = 92.6 rad/s

P = 1.41 MPa

μ = 0.35

ω = 111.12 rad/s

P = 1.83 MPa

μ= 0.42

PSM 2PSM 2Perform similar thermal analysis

and sensitivity studies on real disc

brake model (existing)

Thermal analysis performed at

different simulation conditions

Disc brake model will consists of :Disc rotor

Piston

Guide pins

Caliper

Carrier

Brake pads Real Disc Brake Assembly Model

PSM 2 PLANNING CHARTPSM 2 PLANNING CHART

THANK YOUTHANK YOU

Q & A SessionQ & A Session

analysis steps

disc constrained at inner ring

simple disc brake model geometry material & thermal properties

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