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SUMMARY:An anisotropic elastic-decohesive constitutive relation for sea ic
 e - Han Duc Tran (Vietnamese-German University)
DTSTART:20171208T113000Z
DTEND:20171208T123000Z
UID:TALK96370@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>Co-authors: Deborah L. Sulsky		(University of New Mexico
 )\, Howard L. Schreyer		(University of New Mexico)        <br></span><span
 ><br>When leads in sea ice expose warm underlying ocean to the frigid wint
 er atmosphere\, new ice is formed rapidly by freezing ocean water. Then co
 nvergence or closing of the pack ice forces the new ice in leads to pile u
 p into ridges and to be forced down into keels. Together with thermodynami
 c growth\, these mechanical processes shape the thickness distribution of 
 the ice cover\, and impact the overall strength of pack ice. Specifically\
 , the deformation and strength of ice are not isotropic but vary with the 
 thickness and orientation of the categories. To reflect these facts\, we d
 evelop an anisotropic constitutive model for sea ice consisting an oriente
 d thickness distribution. The model describes anisotropically mechanical r
 esponses in both elastic and failure regimes. In the elastic regime\, the 
 constitutive relation implicitly reflects the strong and weak directions o
 f the pack ice depending on the distribution of thin ice and thicker ice. 
 The existence of open water\, a special  case of thin ice\, is also reflec
 ted in the elastic constitutive relation in which the free-traction condit
 ion is satisfied. In the failure regime\, the model predicts when an initi
 al failure\, i.e. a microcrack\, occurs and what the direction of the fail
 ure is. The evolution of a microcrack to a macrocrack\, i.e. when free-tra
 ction crack surfaces are completely formed\, is also modeled\, and a numer
 ical procedure is proposed to determine the width of cracks. Sample paths 
 in stress space are used to illustrate how the model can simulate failure.
  Several examples of failure surfaces are presented to describe the behavi
 or of ice when varying thickness distributions. The model predictions are 
 also illustrated and compared with previous modeling efforts by examining 
 regions under idealized loading.</span>
LOCATION:Seminar Room 1\, Newton Institute
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