000004843 001__ 4843
000004843 005__ 20141119144558.0
000004843 04107 $$aeng
000004843 046__ $$k2002-06-02
000004843 100__ $$aHopkins, Mark A.
000004843 24500 $$aARCTIC SEA ICE: LARGE-SCALE FRACTURE MECHANICS

000004843 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference
000004843 260__ $$bColumbia University in the City of New York
000004843 506__ $$arestricted
000004843 520__ $$2eng$$aThe ice pack covering northern seas is composed of a mixture of thick ridged and rafted ice, undeformed ice, and open water. Existing ice-ocean models of the Arctic ice pack are large-scale Eulerian continuum models that use a plastic yield surface to characterize the constitutive behavior of the pack. An alternative is to adopt a discontinuous Lagrangian approach and explicitly model ice parcels and the interactions between them. We have constructed a granular sea ice model that consists of thousands of discrete polygonal floes 5-10 km in width. At the beginning of a simulation the ice floes completely fill the Arctic basin and are frozen together. Wind driven deformation of the pack creates relative motion between floes that stretches the viscous-elastic joints between adjacent floes. The stress at each point along the frozen joints is defined by a constitutive model that follows linear loading and unloading paths. After unloading the joint is broken at that point. Fractures propagate along joints forming crack patterns in the model ice pack. The crack patterns define large plates 10-100 km in width that are aggregates of many individual floes. Subsequent deformation occurs along slip lines defined by the crack patterns. Since the usual state of the ice pack is a state of failure, an interesting situation is created in which the initial wind-driven deformation defines the conditions under which subsequent deformation occurs. Simulation results are used to characterize the formation of the aggregate under a divergent deformation state and the dependence of the average area of the aggregate floes on tensile strength, the wind stress gradient, and the size of the individual floes.

000004843 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004843 653__ $$a

000004843 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002
000004843 720__ $$aHopkins, Mark A.$$iThorndike, Alan S.
000004843 8560_ $$ffischerc@itam.cas.cz
000004843 8564_ $$s404243$$uhttps://invenio.itam.cas.cz/record/4843/files/423.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004843 962__ $$r4594
000004843 980__ $$aPAPER