PRESENTATION OUTLINE - Universiti Teknologi Malaysiaarahim/psm_1_presentation_lee.pdf ·...
Transcript of PRESENTATION OUTLINE - Universiti Teknologi Malaysiaarahim/psm_1_presentation_lee.pdf ·...
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
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40
Distance (mm)
Tem
pera
ture
(ºC
)
Upper PadLower Pad
0
50
100
150
200
250
0 5 10 15 20 25 30 35 40Distance (mm)
Tem
pera
ture
(ºC
)
Upper pad leadingUpper pad trailingLower pad leadingLower pad trailing
temperature distribution along center of friction pads
temperature distribution along leading and trailing edges
0
20
40
60
80
100
120
140
160
180
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Time (seconds)
Tem
pera
ture
(ºC
)
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
50
100
150
200
250
300
350
400
450
500
0 5 10 15 20 25 30 35 40
Distance (mm)
Tem
pera
ture
(ºC
)
Upper Pad Initial
Lower Pad Initial
Upper Pad (ω = 111.12 rad/s)
Lower Pad (ω = 111.12 rad/s)
0
50
100
150
200
250
300
0 5 10 15 20 25 30 35 40Distance (mm)
Tem
pera
ture
(ºC
)
Upper pad leadingLower pad leadingUpper pad leading (ω = 111.12 rad/s) Lower pad leading (ω = 111.12 rad/s)
0
50
100
150
200
250
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Time (seconds)
Tem
pera
ture
(ºC
)
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
upper friction pad lower friction pad
*top of diagram is leading edge
0
50
100
150
200
250
300
350
400
450
500
0 5 10 15 20 25 30 35 40Distance (mm)
Tem
pera
ture
(ºC
)
Upper Pad Initial
Lower Pad Initial
Upper Pad (P = 1.83 MPa)
Lower Pad (P = 1.83 MPa)
0
50
100
150
200
250
300
350
0 5 10 15 20 25 30 35 40Distance (mm)
Tem
pera
ture
(ºC
)
Upper pad leadingLower pad leadingUpper pad leading (P = 1.83 MPa) Lower pad leading (P = 1.83 MPa)
0
50
100
150
200
250
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Time (seconds)
Tem
pera
ture
(ºC
)
Upper pad leadingLower pad leadingUpper pad leading (P = 1.83 MPa)Lower pad leading (P = 1.83 MPa)
temperature distribution along center of friction pads temperature distribution along leading edges
temperature increment at leading edges of friction pads
Friction Coefficient = 0.42Friction Coefficient = 0.42
upper friction pad lower friction pad
*top of diagram is leading edge
0
50
100
150
200
250
300
350
400
450
500
0 5 10 15 20 25 30 35 40
Distance (mm)
Tem
pera
ture
(ºC
)
Upper Pad Initial
Lower Pad Initial
Upper Pad (μ = 0.42)
Lower Pad (μ = 0.42)
0
50
100
150
200
250
300
350
0 5 10 15 20 25 30 35 40Distance (mm)
Tem
pera
ture
(ºC
)
Upper pad leadingLower pad leadingUpper pad leading (μ = 0.42) Lower pad leading (μ = 0.42)
0
50
100
150
200
250
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Time (seconds)
Tem
pera
ture
(ºC
)
Upper pad leadingLower pad leadingUpper pad leading (μ = 0.42)Lower pad leading (μ = 0.42)
temperature distribution along center of friction pads temperature distribution along leading edges
temperature increment at leading edges of friction pads
PARAMETERS UPPER FRICTION PAD LOWER FRICTION PAD
Maximum temperature (°C) 312.8 355.7
Simulation time (s) 2 2
PARAMETERS UPPER FRICTION PAD LOWER FRICTION PAD
Maximum temperature (°C) 373.5 429.5
Simulation time (s) 2 2
PARAMETERS UPPER FRICTION PAD LOWER FRICTION PAD
Maximum temperature (°C) 398.3 453.9
Simulation time (s) 2 2
PARAMETERS UPPER FRICTION PAD LOWER FRICTION PAD
Maximum temperature (°C) 375.7 433.9
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
Bolts
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