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#1
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Do you know of engineering papers for what people call brake rotor'warp'?
We're having a conversation among friends when one casually mentions
his wife's rotors "warped". The other jumps on him and declares that street-use rotors don't warp (in general). An Internet search bears him out, as MANY articles say rotor warp is a myth. Googling, we find that brake torque variation is mostly from uneven pad deposition buildup (i.e., disc thickness variation) and axial runout. But then it gets confusing as the more enlightened sources begin to mention thermo elastic instability hotspots and breaking judder into low frequency cold judder and high frequency hot judder. The heated discussion went on. And so did the confusion. For more than a few beers. My question? While we now know rotors rarely actually warp, does anyone know of a good scientific or engineering paper explaining the TRUE causes of brake related judder in street cars? |
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#2
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Do you know of engineering papers for what people call brakerotor 'warp'?
On Feb 14, 11:44*pm, Joe Mastroianni > wrote:
> does anyone know of a good > scientific or engineering paper explaining the TRUE causes of brake > related judder in street cars? Here's 8 pages of "words"... that conform to what I think I might have once known. http://www.powerbrake.co.za/download..._01_judder.pdf ----- - gpsman |
#3
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Do you know of engineering papers for what people call brakerotor 'warp'?
On 02/14/2013 08:44 PM, Joe Mastroianni wrote:
> We're having a conversation among friends when one casually mentions > his wife's rotors "warped". > > The other jumps on him and declares that street-use rotors don't warp (in > general). An Internet search bears him out, as MANY articles say rotor > warp is a myth. > > Googling, we find that brake torque variation is mostly from uneven pad > deposition buildup (i.e., disc thickness variation) and axial runout. But > then it gets confusing as the more enlightened sources begin to mention > thermo elastic instability hotspots "thermo-elastic instability hotspots"?????? if you mean "heat distortion", then say so - don't try to confuse the proles. > and breaking judder into low > frequency cold judder and high frequency hot judder. > > The heated discussion went on. And so did the confusion. > For more than a few beers. > > My question? > > While we now know rotors rarely actually warp, does anyone know of a good > scientific or engineering paper explaining the TRUE causes of brake > related judder in street cars? there's no need for and "engineering or scientific" paper on this stuff - it's trivial for anyone that's done the right disciplines in engineering and/or materials. as to the origin of how it affects the car, the pulsing effect you get is a result of two factors: 1. local elastic distortion of the disk/hub interface. 2. use of single-piston/single-sided brake calipers. #2 is particularly relevant because before they came along, brake disks were still subject to the same distortions they ever were, but any side-to side variance has hydraulic pressures balanced within the caliper so they're not felt at the pedal. with single-sided, the weight inertia delta between pushing a piston, then pulling the whole caliper, creates a strong pulsing effect at the pedal. hence #1 becomes much more noticeable. bottom line, it's simple enough to fix, and simple enough to diagnose. just stay away from hysterical internet bull****ters, clean your hub interfaces, use a little antiseize and a torque wrench, and you'll be fine. -- fact check required |
#4
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Do you know of engineering papers for what people call brakerotor 'warp'?
On 02/15/2013 10:52 AM, gpsman wrote:
> On Feb 14, 11:44�pm, Joe Mastroianni > wrote: >> does anyone know of a good >> scientific or engineering paper explaining the TRUE causes of brake >> related judder in street cars? > > Here's 8 pages of "words"... that conform to what I think I might have > once known. > http://www.powerbrake.co.za/download..._01_judder.pdf > ----- > > - gpsman > words, but not a paper, just advertising. their cited uneven disk thickness is relatively uncommon. distortion from the plane is very common indeed. it's the asymmetry of a caliper's component momenta that causes pulsing in the hydraulics. opposed pistons dynamically self-equilibrate - single sided calipers cannot. -- fact check required |
#5
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Do you know of engineering papers for what people call brakerotor 'warp'?
On Fri, 15 Feb 2013 16:51:20 -0800, jim beam wrote:
> words, but not a paper, just advertising. Yes, I'm looking for 'real' scientific engineering papers. All these (which are decidedly NOT engineering papers!) say rotors aren't warping, but as you noted, it might just be advertising. CENTRIC: Pad and Rotor Bed-In Theory, Definitions and Procedures http://www.centricparts.com/files/Ce...n%20Theory.pdf AKEBONO: Brake Noise, Vibration, Harshness, causes http://www.akebonobrakes.com/company...kebono_NVH.pdf POWERBRAKE: The final word on brake judder and "warped" discs http://www.powerbrake.co.za/download..._01_judder.pdf BREMBO: Judder caused by improper bedding procedure http://www.brembo.com/en/car/Racing/...20CATALOGO.pdf |
#6
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Do you know of engineering papers for what people call brakerotor 'warp'?
On Fri, 15 Feb 2013 16:48:16 -0800, jim beam wrote:
> "thermo-elastic instability hotspots"?????? if you mean "heat > distortion", then say so - don't try to confuse the proles. The proletariat be damned, I reach out to the literati to explain what "really" causes brake judder (because it's not rotor warp)! Googling, I found these on the bimmer boards so far that I'm reading: "Aspects of disc brake judder" Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering http://pid.sagepub.com/content/217/6/419.full.pdf Analysis of the vehicle brake judder problem by employing a simplified source–path–receiver model Acoustics and Dynamics Laboratory, Department of Mechanical Engineering, The Ohio State University, Columbus, Ohio, USA http://www.researchgate.net/publicat...7d38711887.pdf A Parametric Study of Brake Roughness Robert Bosch Corporation http://sem-proceedings.com/20i/sem.o...-Roughness.pdf Judder, Diagnosis, & Prevention, Mohamed Khalid Abdelhamid, AlliedSignal Automotive, Europe http://sem-proceedings.com/14i/sem.o...Prevention.pdf Improved mathematical models of vehicle brake judder and experimental observations Osman Taha Sen, Rajendra Singh Acoustics and Dynamics Laboratory, Department of Mechanical and Aerospace Engineering, The Ohio State University, http://www.mecheng.osu.edu/adl/files/adl/C12-1.pdf Judder vibration in disc brakes excited by thermoelastic instability Oscar Altuzarra, Enrique Amezua, Rafael Avilés, Alfonso Hernández, (2002), Engineering Computations, Vol. 19 Iss: 4, pp.411 - 430 http://www.ehu.es/compmech/welcome/d...mputations.pdf Experimental Analysis of Disc Thickness Variation Development in Motor Vehicle Brakes School of Aerospace, Mechanical & Manufacturing Engineering (SAMME) http://researchbank.rmit.edu.au/eser.../Rodriguez.pdf Thermal Brake Judder Investigations Using a High Speed Dynamometer David Bryant, John Fieldhouse, Andrew Crampton and Chris Talbot, University of Huddersfield http://eprints.hud.ac.uk/3878/1/2008-01-0818.pdf Braking Process in Automobiles: Investigation of the Thermoelastic Instability Phenomenon M. Eltoukhy and S. Asfour, Department of Industrial Engineering, College of Engineering, University of Miami http://cdn.intechweb.org/pdfs/5380.pdf Brake Vibration and Noise - A Review and Discussion Dihua Guan, State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing, China http://www.acoustics.asn.au/conferen...papers/p46.pdf NVH Simulation Technology for Disc Brake Calipers Hitachi, Suzuki Yoichi Kumemura Hayuru Inoue Yuichi Takagi Shinji Suzuki http://www.hitachi.com/ICSFiles/afie...009_07_107.pdf SURFACE TEMPERATURE DISTRIBUTION IN A COMPOSITE BRAKE ROTOR A.A. Adebisi1, M.A. Maleque1 and Q.H. Shah Department of Manufacturing and Materials Engineering http://ejum.fsktm.um.edu.my/article/1146.pdf DISCUSSION OF THE CHARACTERISTICS OF BRAKE JUDDER AND THE NECESSARY DATA ACQUISITION SYSTEM FOR COMPLETE ANALYSIS D. Bryant, A. Crampton, J. Fieldhouse and C. Talbot University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK http://eprints.hud.ac.uk/3797/1/10_P...l_D_Bryant.pdf Order domain analysis of speed-dependent friction-induced torque in a brake experiment Osman Taha Sen, Jason T. Dreyer, Rajendra Singh Acoustics and Dynamics Laboratory, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210, USA http://www.mecheng.osu.edu/adl/files/adl/J187.pdf |
#7
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Do you know of engineering papers for what people call brakerotor 'warp'?
jim beam wrote:
> bottom line, it's simple enough to fix, and simple enough to diagnose. > just stay away from hysterical internet bull****ters, clean your hub > interfaces, use a little antiseize and a torque wrench, and you'll be fine. Most seem to say it's uneven pad deposition causing DTV where the pad deposition is self inflicted by the driver. So, the best cure is to change your driving habits. At least that's what most say. |
#8
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Do you know of engineering papers for what people call brakerotor 'warp'?
On 02/15/2013 05:49 PM, Zen wrote:
> jim beam wrote: > >> bottom line, it's simple enough to fix, and simple enough to diagnose. >> just stay away from hysterical internet bull****ters, clean your hub >> interfaces, use a little antiseize and a torque wrench, and you'll be fine. > > Most seem to say it's uneven pad deposition causing DTV > where the pad deposition is self inflicted by the driver. > > So, the best cure is to change your driving habits. > At least that's what most say. > that's doesn't in the least explain how i go to a shop for tire replacement, and driving home, my disks are "warped". i take the wheels off, clean up the hub, torque with a three-stage sequence, and then my disks are unwarped again. -- fact check required |
#9
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Do you know of engineering papers for what people call brakerotor 'warp'?
On 02/15/2013 05:44 PM, Joe Mastroianni wrote:
> On Fri, 15 Feb 2013 16:48:16 -0800, jim beam wrote: > >> "thermo-elastic instability hotspots"?????? if you mean "heat >> distortion", then say so - don't try to confuse the proles. > > The proletariat be damned, I reach out to the literati to explain > what "really" causes brake judder (because it's not rotor warp)! > > Googling, I found these on the bimmer boards so far that I'm reading: > > "Aspects of disc brake judder" > Proceedings of the Institution of Mechanical Engineers, > Part D: Journal of Automobile Engineering > http://pid.sagepub.com/content/217/6/419.full.pdf quickly scanning, i see nothing on caliper asymmetry. > > Analysis of the vehicle brake judder problem by employing a simplified source–path–receiver model > Acoustics and Dynamics Laboratory, > Department of Mechanical Engineering, > The Ohio State University, Columbus, Ohio, USA > http://www.researchgate.net/publicat...7d38711887.pdf that one presumes disk thickness variation, nothing on caliper dynamics. > > A Parametric Study of Brake Roughness > Robert Bosch Corporation > http://sem-proceedings.com/20i/sem.o...-Roughness.pdf etc. > > Judder, Diagnosis, & Prevention, > Mohamed Khalid Abdelhamid, AlliedSignal Automotive, Europe > http://sem-proceedings.com/14i/sem.o...Prevention.pdf > > Improved mathematical models of vehicle brake judder and experimental observations > Osman Taha Sen, Rajendra Singh > Acoustics and Dynamics Laboratory, Department of Mechanical and Aerospace Engineering, > The Ohio State University, > http://www.mecheng.osu.edu/adl/files/adl/C12-1.pdf > > Judder vibration in disc brakes excited by thermoelastic instability > Oscar Altuzarra, Enrique Amezua, Rafael Avilés, Alfonso Hernández, (2002), > Engineering Computations, Vol. 19 Iss: 4, pp.411 - 430 > http://www.ehu.es/compmech/welcome/d...mputations.pdf > > Experimental Analysis of Disc Thickness Variation Development in Motor Vehicle Brakes > School of Aerospace, Mechanical & Manufacturing Engineering (SAMME) > http://researchbank.rmit.edu.au/eser.../Rodriguez.pdf > > Thermal Brake Judder Investigations Using a High Speed Dynamometer > David Bryant, John Fieldhouse, Andrew Crampton and Chris Talbot, University of Huddersfield > http://eprints.hud.ac.uk/3878/1/2008-01-0818.pdf > > Braking Process in Automobiles: Investigation of the Thermoelastic Instability Phenomenon > M. Eltoukhy and S. Asfour, Department of Industrial Engineering, College of Engineering, University of Miami > http://cdn.intechweb.org/pdfs/5380.pdf > > Brake Vibration and Noise - A Review and Discussion > Dihua Guan, State Key Laboratory of Automotive Safety and Energy, > Tsinghua University, Beijing, China > http://www.acoustics.asn.au/conferen...papers/p46.pdf > > NVH Simulation Technology for Disc Brake Calipers > Hitachi, Suzuki Yoichi Kumemura Hayuru Inoue Yuichi Takagi Shinji Suzuki > http://www.hitachi.com/ICSFiles/afie...009_07_107.pdf > > SURFACE TEMPERATURE DISTRIBUTION IN A COMPOSITE BRAKE ROTOR > A.A. Adebisi1, M.A. Maleque1 and Q.H. Shah > Department of Manufacturing and Materials Engineering > http://ejum.fsktm.um.edu.my/article/1146.pdf > > DISCUSSION OF THE CHARACTERISTICS OF BRAKE JUDDER AND THE NECESSARY DATA ACQUISITION SYSTEM FOR COMPLETE ANALYSIS > D. Bryant, A. Crampton, J. Fieldhouse and C. Talbot > University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK > http://eprints.hud.ac.uk/3797/1/10_P...l_D_Bryant.pdf > > Order domain analysis of speed-dependent friction-induced torque in a brake experiment > Osman Taha Sen, Jason T. Dreyer, Rajendra Singh > Acoustics and Dynamics Laboratory, > Department of Mechanical and Aerospace Engineering, > The Ohio State University, Columbus, OH 43210, USA > http://www.mecheng.osu.edu/adl/files/adl/J187.pdf i'll try to look at the rest, but seriously, most people who don't know are chasing their tails. those that do know aren't going to say much because they're not going to do two things: 1. they're /definitely/ not going to kill a cash cow which is selling new disks way before they're worn. 2. they're not going to stop using single-sided calipers because they're essential to macpherson strut suspension being able to have a negative scrub radius. so you're just going to have to keep sucking it up and coughing it up. -- fact check required |
#10
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Do you know of engineering papers for what people call brakerotor 'warp'?
Joe Mastroianni > wrote:
>All these (which are decidedly NOT engineering papers!) say rotors >aren't warping, but as you noted, it might just be advertising. Rotors warp for the same reason that lugs break off: idiots with lug wrenches. It is correct that rotors do not warp by themselves, but I have seen plenty of cases of warped rotors, all of which can probably be traced to some idiot mistorquing lugs. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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