FACULTY OF MECHANICAL ENGINEERING PRESENTATION OUTLINE PRESENTATION - - PowerPoint PPT Presentation

PRESENTER : MOHD MUZAKKIR AMIN BIN MOKHTAR

SUPERVISOR : DR. ABD RAHIM BIN ABU BAKAR

FACULTY OF MECHANICAL ENGINEERING

PRESENTATION OUTLINE PRESENTATION OUTLINE

• INTRODUCTION

INTRODUCTION

• OBJECTIVES

OBJECTIVES

• SCOPES OF STUDY

SCOPES OF STUDY

• LITERATURE

LITERATURE

• METHODOLOGY

METHODOLOGY

• RESULTS & DISCUSSION

RESULTS & DISCUSSION

• CONCLUSION

CONCLUSION

INTRODUCTION INTRODUCTION

• Brake system

Brake system Kinetic energy Kinetic energy thermal energy thermal energy (heat) (heat) Friction Friction

• Drum brake

Drum brake

• Rotating cylindrical drum

Rotating cylindrical drum

• Stationary shoes

Stationary shoes

Types of Drum Brake Types of Drum Brake

Why need to understand the working principles ? ? ?

BRAKE SQUEAL BRAKE SQUEAL

• Phenomenon of dynamic instability

Phenomenon of dynamic instability Natural frequency/ Natural frequency/ ies ies friction couple friction couple

• Self

Self -

• excited + friction

excited + friction-

• induced vibration

induced vibration

excitation at

BRAKE NOISE & VIBRATION BRAKE NOISE & VIBRATION

Weiming Liu & Jerome L. Ppfeifer

Market Requirements Market Requirements

Country Country Noise Noise Friction Friction Coefficient Coefficient Wear Wear Dust Dust USA USA A A C C A A B B Europe Europe B B A A B B C C Japan Japan A A C C B B B B Developing Developing Countries Countries C C B B A A C C Malaysia Malaysia A A A A B B A A

3rd Malaysian Brake Friction Material Colloquium 2006 (Chong Fah Ming, 2006)

OBJECTIVES OBJECTIVES

• Identify the squeal characteristics of a drum

Identify the squeal characteristics of a drum brake model using numerical method brake model using numerical method

• Investigate the effects of different parameters

Investigate the effects of different parameters

• n squeal
• n squeal

i.e. i.e. pressure, sliding velocity, friction pressure, sliding velocity, friction coefficient coefficient

SCOPES OF STUDY SCOPES OF STUDY

• Investigate dynamic instability of an

Investigate dynamic instability of an existing /

existing / validated validated drum brake model

drum brake model

• Perform the

Perform the Dynamic Transient Analysis

Dynamic Transient Analysis using

using commercial software package commercial software package

• Write + verify a

Write + verify a Matlab Matlab program code program code (Fast Fourier Transform (Fast Fourier Transform -

• FFT)

FFT) Time domain Time domain Frequency domain Frequency domain

• Compare the results obtained from DTA and

Compare the results obtained from DTA and CEA CEA

THEORY OF A DRUM THEORY OF A DRUM BRAKE SQUEAL BRAKE SQUEAL

Simple binary flutter model of a small section

• f the drum/ lining interface

APPROACHES EXPERIMENTAL ANALYTICAL FE SIMULATION

TOOLS TOOLS

EXPERIMENTAL EVIDENCES EXPERIMENTAL EVIDENCES

• Tendency to squeal increases with increasing

Tendency to squeal increases with increasing pressure pressure

• Squeal is most prevalent at temperature below

Squeal is most prevalent at temperature below 100 100 ° °C C

• Squeal is likely a result of

Squeal is likely a result of “ “ early morning early morning sharpness sharpness” ” -

• high

high μ

μ

PREDICTING METHODS NORMAL MODE COMPLEX EIGENVALUE DYNAMIC TRANSIENT

TYPICAL SIMULATION SCHEME TYPICAL SIMULATION SCHEME

COMPONENTS GENERATION DRUM BRAKE ASSEMBLY CONTACT ANALYSIS CEA / DTA WEAR EFFECT STRUCTURAL MODIFICATIONS VALIDATION VALIDATION FE MODEL STABILITY ANALYSIS

METHODOLOGY METHODOLOGY

MODEL CONSTRUCTION DTA RES ULTS Performing stability analysis Identify squeal characteristics MATLAB PROGRAMMING Abaqus Pre-processor FFT procedure

Prediction of unstable frequencies

EXPLICIT DYNAMIC ANALYSIS EXPLICIT DYNAMIC ANALYSIS

• Basic equations

Basic equations -

• (central differential)

(central differential)

• Lumped

Lumped diagnol diagnol mass matrices mass matrices

Equation of motion acceleration

int ) ( ) ( ) ( t ext t t

P P u M − = & &

) (

int ) ( ) ( 1 ) ( t ext t t

P P M u − =

−

& &

Stability limits velocity displacement

) ( ) ( ) ( ) 2 ( ) 2 (

2

t t t t t t t t

u t t u u & & & & Δ + Δ + =

Δ + Δ − Δ +

) 2 ( ) ( ) ( ) ( t t t t t t t

u t u u

Δ + Δ + Δ +

Δ + = &

max

2 ω = Δ stable t

DRUM BRAKE MODEL DRUM BRAKE MODEL

MATERIAL PROPERTIES MATERIAL PROPERTIES

PARAMETER PARAMETER VALUE VALUE DENSITY OF DRUM DENSITY OF DRUM MODULUS YOUNG MODULUS YOUNG 7673 kg/ m3 7673 kg/ m3 104 104 GPa GPa DENSITY OF SHOE DENSITY OF SHOE MODULUS YOUNG MODULUS YOUNG 8762 kg/ m3 8762 kg/ m3 250 250 GPa GPa DENSITY OF LINING DENSITY OF LINING MODULUS YOUNG MODULUS YOUNG 2638 kg/ m3 2638 kg/ m3 3.1 3.1 GPa GPa

OPERATING OPERATING CONDITIONS CONDITIONS

P P = 15 & 35 bar = 15 & 35 bar

ω ω = 10 & 14

= 10 & 14 rad/ s rad/ s

μ μ = 0.40 & 0.45

= 0.40 & 0.45

Contact Contact Schemes Schemes

Kinematic contact method Penalty contact method

Kinemat ic f = 2739 , 3436 , 4233 Hz Penalty

CEA results CEA results

Mode Shapes Mode Shapes Frequency, Hz Frequency, Hz Mode 4 Mode 4 1441 1441 Mode 6 Mode 6 2675 2675 Mode 8 Mode 8 3489 3489 Mode 10 Mode 10 4305 4305 Mode 12 Mode 12 5497 5497

Friction Friction Coefficient Coefficient

µ = 0.40 µ = 0.45

µ = 0.40 f = 2739 Hz µ = 0.45 f = 2739 , 3436 , 4233 Hz

Sliding Sliding Velocity Velocity

ω = 10 rad/ s ω = 14 rad/ s

ω = 10 rad/ s

f = 1549 , 2749 Hz

ω = 14 rad/ s

f = 1290 , 2740 , 2902 3439 , 3869 , 4138 4621 Hz

Contact Contact Pressure Pressure

P = 15 bar P = 35 bar

P = 15 bar f = 2744 Hz P = 35 bar f = 2744 , 3775 , 4188 Hz

CONCLUSIONS CONCLUSIONS

• Harmonic vibration

Harmonic vibration – – continuous squeal continuous squeal

• Good correlation between CEA and DTA

Good correlation between CEA and DTA

• Kinematic

Kinematic contact method gives better contact method gives better prediction compared to penalty contact method prediction compared to penalty contact method

• The changes in those parameters will affect the

The changes in those parameters will affect the propensity of squeals propensity of squeals

RECOMMENDATIONS RECOMMENDATIONS

• Consider the effects of such parameters like

Consider the effects of such parameters like temperature and humidity on squeal occurrence temperature and humidity on squeal occurrence

• Investigate the influences of lining shape and

Investigate the influences of lining shape and material properties, i.e. Young material properties, i.e. Young’ ’ s modulus, on s modulus, on squeal propensity squeal propensity

• Includes the nonlinear friction characteristics

Includes the nonlinear friction characteristics at the drum and lining interfaces at the drum and lining interfaces