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SUMMARY:Why is brake squeal so twitchy?  Modelling and sensitivity studies
  of friction-driven vibration - Prof Jim Woodhouse
DTSTART:20090522T133000Z
DTEND:20090522T143000Z
UID:TALK17056@talks.cam.ac.uk
CONTACT:Anita Clayson
DESCRIPTION:Friction-driven vibration occurs in a number of contexts\, fro
 m the violin string to brake squeal and machine tool vibration.  A review 
 of some key phenomena and approaches will be given\, then the talk will fo
 cus on a particular aspect\, the "twitchiness" of squeal and its relatives
 .  It is notoriously difficult to get repeatable measurements of brake squ
 eal\, and this has been regarded as a problem for model testing and valida
 tion.  But this twitchiness is better regarded as an essential feature of 
 the phenomenon\, to be addressed by any model with pretensions to predicti
 ve power.  Recent work examining sensitivity of friction-excited vibration
  in a system with a single-point frictional contact will be described.  Th
 is involves theoretical prediction of nominal instabilities and their sens
 itivity to parameter uncertainty\, compared with the results of a large-sc
 ale experimental test in which several thousand squeal initiations were ca
 ught and analysed in a laboratory system.  Mention will also be made of a 
 new test rig\, which attempts to fill a gap in knowledge of frictional mat
 erial properties by measuring a parameter which occurs naturally in any li
 nearised stability analysis\, but which has never previously been measured
 .\n
LOCATION:Department of Engineering - LR6
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