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