DISC BRAKING VIBRATION MODELLING AND MEASUREMENT NIKHIL TT S7 M2 NO: 41 COLLEGE OF ENGINEERING TRIVANDRUM
DISC BRAKING VIBRATION MODELLING AND MEASUREMENT
NIKHIL TTS7 M2NO: 41
COLLEGE OF ENGINEERING TRIVANDRUM
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
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.
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=559fHZsCRXpn-M:&docid=XI9qN2rOfYwg-M&ei=5UX4VbWoGo2SuATigK3wBg&tbm=isch&ved=0CDQQMygDMANqFQoTCPWuoMS5-ccCFQ0JjgodYkALbg
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.com/viewtopic.php?f%3D51%26t%3D135908&h=285&w=498&tbnid=Ss9PqMHj-04-yM:&docid=EwKKtfr8dpYU3
DISC BRAKE SYSTEM
SOURCE: autohowstuff.com
ADVANTAGES
Greater amounts of heat to atmosphere Cooling more rapid Rotors scrape off water more efficiently Don’t need periodic maintenance Easier to service
DISADVANTAGES
Rotors warp easier Hard to use as parking brakes Discomfort from brake vibration Prone to noise
EXPERIMENTAL METHOD
• Driving unit
• Braking unit
• Measurement facilities
DRAG-TYPE BRAKE DYNAMO METER
Ac motor of 14.9 kW and 1500 rpmManual gear box
Front disc brake assembly of a passenger carHydraulic jack to apply pressure
MEASUREMENT FACILITIES
• Tachometer• Pressure gauge• Accelerometer • Charge amplifier• Infrared thermometer• Load cell
SCHEMATIC DIAGRAM OF BRAKE DYNAMOMETER
Source: journal “An experimental study of automotive disk brake vibration”
EXPERIMENTAL PROCEEDING
• Vehicle speed :10.75, 17, 20.8 km/hr• Brake pressure : 2.5 to 20 bar• Temperature : 50 °C TO 70 °C
VIBRATION FREQUENCY ANALYSIS• Time domain signal• Frequency domain signal• Fourier analysis• Fast Fourier Transform (FFT) using MATLAB to
produce Power Spectrum Density (PSD)
Source: journal “An experimental study of automotive disk brake vibration”
RESULTS
Source: journal “An experimental study of automotive disk brake vibration”
Source: journal “An experimental study of automotive disk brake vibration”
Source: journal “An experimental study of automotive disk brake vibration”
STUDY ON RESULTS
• 27 tests• Peaks in the vibration frequencies are
dominated at 4.4 kHz• Depends on sliding speed• Independent on frequency content
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
EFFECT OF VEHICLE SPEED
Source: journal “An experimental study of automotive disk brake vibration”
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
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
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
THANK YOU