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 thermal energy Kinetic energy thermal energy (heat) (heat) Friction Friction • • Drum brake - Rotating cylindrical drum Rotating cylindrical drum Drum brake - - Stationary shoes Stationary shoes -

? ? Why need to understand the working principles ? Types of Drum Brake Types of Drum Brake

BRAKE SQUEAL BRAKE SQUEAL • Phenomenon of dynamic instability • Phenomenon of dynamic instability at excitation Natural frequency/ ies ies friction couple Natural frequency/ friction couple • Self • Self - -excited + friction excited + friction- -induced vibration induced vibration

BRAKE NOISE & VIBRATION BRAKE NOISE & VIBRATION Weiming Liu & Jerome L. Ppfeifer

Market Requirements Market Requirements Country Noise Friction Wear Dust Country Noise Friction Wear Dust Coefficient Coefficient USA A C A B USA A C A B Europe B A B C Europe B A B C Japan A C B B Japan A C B B Developing C B A C Developing C B A C Countries Countries Malaysia A A B A Malaysia A A B A 3 rd 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 on squeal on squeal i.e. pressure, sliding velocity, friction i.e. 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 drum brake model drum brake model validated • 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 - - FFT) FFT) (Fast Fourier Transform Time domain Frequency domain Time 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 of the drum/ lining interface

ANALYTICAL FE SIMULATION APPROACHES EXPERIMENTAL 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 ° ° C C 100 • Squeal is likely a result of • Squeal is likely a result of “ “ early morning early morning μ high μ sharpness” ” - - high sharpness

COMPLEX NORMAL MODE EIGENVALUE PREDICTING METHODS DYNAMIC TRANSIENT

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

METHODOLOGY METHODOLOGY Prediction of unstable frequencies MODEL MATLAB CONSTRUCTION PROGRAMMING FFT procedure Abaqus Pre-processor DTA RES ULTS Performing stability Identify squeal analysis characteristics

EXPLICIT DYNAMIC ANALYSIS EXPLICIT DYNAMIC ANALYSIS • Basic equations • Basic equations - - (central differential) (central differential) • Lumped • Lumped diagnol diagnol mass matrices mass matrices = − & & M u P P Equation of motion ( t ) ( t ) ext ( t ) int − = − & & 1 u M ( P P ) acceleration ( t ) ( t ) ext ( t ) int

Δ + Δ t t + Δ = + ( t t ) ( t ) & & & & velocity u u u Δ Δ t t ( t ) + − 2 ( t ) ( t ) 2 2 = + Δ & u u t u displacement + Δ + Δ Δ ( t t ) ( t ) ( t t ) t + ( t ) 2 2 Δ stable = t Stability limits ω max

DRUM BRAKE MODEL DRUM BRAKE MODEL

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

OPERATING OPERATING CONDITIONS CONDITIONS P = 15 & 35 bar = 15 & 35 bar P ω = 10 & 14 ω = 10 & 14 rad/ s rad/ s μ = 0.40 & 0.45 μ = 0.40 & 0.45

Schemes Contact Schemes Contact Kinematic contact method Penalty contact method

f = 2739 , 3436 , 4233 Hz Kinemat ic Penalty

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

Coefficient Coefficient Friction Friction 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

Pressure Pressure Contact Contact 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’ ’ s modulus, on s modulus, on material properties, i.e. Young 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