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SUMMARY:Micromechanics of sea ice frictional slip from test basin scale ex
 periments - Peter Sammonds (University College London)
DTSTART:20171207T100000Z
DTEND:20171207T110000Z
UID:TALK96331@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>Co-authors: Daniel Hatton and Daniel Feltham<br></span><
 br>We have performed high-resolution double-direct shear friction experime
 nts on saline ice floes in the HSVA environmental test basin. The friction
 al motion was predominantly stick-slip.&nbsp\; Shear stresses\, normal str
 esses\, local strains and slip displacement were measured along the slidin
 g faults\, and acoustic emissions were monitored. High resolution measurem
 ents during a single stick- slip cycle at several positions along the faul
 t allowed us to identify two phases of frictional slip: a nucleation phase
 \, where a nucleation zone begins to slip before the rest of the fault\, a
 nd a propagation phase when the entire fault is slipping. We employed a co
 nstitutive relation for frictional slip derived from the physics of asperi
 ty-asperity contact. We find our experimental data conform reasonably with
  this frictional law once slip weakening is introduced.&nbsp\; We deduce t
 he interfacial faults failed in the stick-slip cycle through the process o
 f brittle failure of asperities in shear\, and at higher velocities\, fric
 tional heating\, localized surface melting and hydrodynamic lubrication.
LOCATION:Seminar Room 1\, Newton Institute
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