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SUMMARY:Friction of Sea Ice - Erland Schulson (Dartmouth College)
DTSTART:20171106T100000Z
DTEND:20171106T110000Z
UID:TALK94507@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>Friction of sea ice plays a fundamental role in a variet
 y of geophysical and engineering scenarios. Examples include ridging and r
 afting\, ice-induced loads on offshore structures and the physics of britt
 le compressive failure. In this paper attention is focused on the characte
 ristics of static friction and frictional sliding of ice upon ice at veloc
 ities of around 0.1 m s-1 (~10 km/day) and lower\, at homologous temperatu
 res greater than around <i>Th</i> =0.85 (>-40 o C). The coefficients of bo
 th static and kinetic friction are described and then discussed in terms o
 f the underlying physical processes. At root is creep deformation of asper
 ities. Creep leads to an increase in contact area and thus to an increase 
 in the coefficient of static friction with increasing time under load. Cre
 ep leads also to an increase in the coefficient of kinetic friction with i
 ncreasing velocity at lower speeds. At higher speeds\, localized melting o
 f asperities sets in\, via frictional heating\, and this leads to a decrea
 se in the kinetic coefficient with increasing velocity. Modeling indicates
  that the velocity that marks the transition scales as $V_t \\propto a \\D
 elta T^2$</span> where $a$ denotes asperity size and $\\Delta T$\, the dif
 ference in temperature between the melting point and the body of ice. Impl
 ications for sea ice mechanics are discussed.<br><br><br><br>
LOCATION:Seminar Room 1\, Newton Institute
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