This document discusses modeling and measuring vibration in disc braking systems. It describes the importance of studying brake vibration to improve vehicle comfort. The experimental method used a brake dynamometer to measure vibration at different vehicle speeds and brake pressures. Testing showed peak vibration occurred at 4.4 kHz and amplitude decreased with increasing speed and pressure. The conclusion is that the dynamometer can effectively measure brake vibration and changes in operation parameters, like speed and pressure, influence vibration levels.

1. DISC BRAKING VIBRATION
MODELLING AND MEASUREMENT
NIKHIL TT
S7 M2
NO: 41
COLLEGE OF ENGINEERING TRIVANDRUM

2. CONTENTS
• Importance
• Introduction
• Experimental method
• Experimental proceeding
• Vibration frequency analysis
• Results
• Study on results
• Influence of applied load variations
• Effect of vehicle speed
• Conclusion
• References

3. IMPORTANCE
• Disc brakes are simple and reliable in adventures
cycling
• Considered as most powerful brakes in luxury
and modern vehicles
• Extensive studies on analysis and investigation of
disc brake vibration on the possibilities of
eliminating brake vibration to improve vehicle
users’ comfort.

4. INTRODUCTION
• Common place on vehicles since 1960
• Extensively uses in modern vehicles
• Disc brakes uses friction to create braking power
• Create braking power by forcing flat friction pads
against the sides of the rotating disc
• Disc brake assemblies consists of a caliper, brake pads
and a rotor
SOURCE:
https://www.google.co.in/imgres?imgurl=http://www.carbibles.com/images/basicdiscbrake.jpg&imgrefurl=http://www.carbibles.com/brake_bible.html&h=480&w=640&tbnid=559fHZsC
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5. INTRODUCTION
Higher applied forces
can be used in disc
brakes than in drum
brakes, because the
design of the rotor is
stronger than the design
of the drum.
Disc versus drum brakes
SOUSCE:
https://www.google.co.in/imgres?imgurl=http://i258.photobucket.com/albums/hh264/fjcamper/SweptArea.jpg&imgrefurl=http://www.shoptalkforums.co
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6. DISC BRAKE SYSTEM
SOURCE: autohowstuff.com

8. ADVANTAGES
 Greater amounts of heat to atmosphere
 Cooling more rapid
 Rotors scrape off water more efficiently
 Don’t need periodic maintenance
 Easier to service

9. DISADVANTAGES
 Rotors warp easier
 Hard to use as parking brakes
 Discomfort from brake vibration
 Prone to noise

10. EXPERIMENTAL METHOD
• Driving unit
• Braking unit
• Measurement facilities
DRAG-TYPE BRAKE DYNAMO METER
Ac motor of 14.9 kW and 1500 rpm
Manual gear box
Front disc brake assembly of a passenger car
Hydraulic jack to apply pressure

11. MEASUREMENT FACILITIES
• Tachometer
• Pressure gauge
• Accelerometer
• Charge amplifier
• Infrared thermometer
• Load cell

12. SCHEMATIC DIAGRAM OF BRAKE DYNAMOMETER
Source: journal “An experimental study of automotive disk brake vibration”

13. EXPERIMENTAL PROCEEDING
• Vehicle speed :10.75, 17, 20.8 km/hr
• Brake pressure : 2.5 to 20 bar
• Temperature : 50 °C TO 70 °C

14. VIBRATION FREQUENCY ANALYSIS
• Time domain signal
• Frequency domain signal
• Fourier analysis
• Fast Fourier Transform (FFT) using MATLAB to
produce Power Spectrum Density (PSD)

15. Source: journal “An experimental
study of automotive disk brake
vibration”

16. RESULTS
Source: journal “An
experimental study of
automotive disk brake
vibration”

17. Source: journal “An
experimental study of
automotive disk brake
vibration”

18. Source: journal “An
experimental study
of automotive disk
brake vibration”

19. STUDY ON RESULTS
• 27 tests
• Peaks in the vibration frequencies are dominated
at 4.4 kHz
• Depends on sliding speed
• Independent on frequency content

20. INFLUENCE OF APPLIED LOAD
VARIATIONS
• Maximum vibration amplitude occurs at a frequency
of approximately 4.4 kHz
• High vibration at lower pressure
• When pressure increases the vibration level decreases

21. EFFECT OF VEHICLE SPEED
Source: journal “An
experimental study of
automotive disk brake
vibration”

22. EFFECT OF VEHICLE SPEED
• Increase of sliding speed decreases the vibration
amplitude
• So automotive vibration frequently occurs at low
velocity
• Vibration amplitude decreases linearly with disk velocity
up to a minimum value and then stays approximately
constant

23. CONCLUSION
• Dynamometer is designed for the purpose of measurement of
brake vibration generated by friction
• The peak value of vibration amplitude is dominant at frequency of
4.4 kHz
• Vibration level decreases with increases of sliding speed
• Vibration level decreases with increases of applied pressure

24. REFERENCES
• Amr M. M. Rabia, Nouby M. Ghazaly, M.M. Salem, Ali M. Abd-El-Tawwab The
International Journal of Engineering And Science, Volume 2, Issue 01, Pages
194-200, 2013
• Swapnil R. Abhang, D.P. Bhaskar, P.G. Students & Associate Professor
Department of Mechanical Engineering , SRES College of Engineering , Pune
University, Kopargaon, India, International Journal of Engineering Trends
and Technology, Volume 8, Pages 165-167, Feb 2014
• Rob Redfied, Department of Engineering Mechanics, U.S. Air Force Academy
, Colorado Springs 80919, USA, The conference of the International Sports
Engineering Association, volume 72, Pages 471-476, 2014