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SUMMARY:Influence of anisotropic rheology of columnar ice on wave propagat
 ion and bearing capacity - Aleksey Marchenko (University Centre in Svalbar
 d (UNIS))
DTSTART:20220926T094500Z
DTEND:20220926T103000Z
UID:TALK178358@talks.cam.ac.uk
DESCRIPTION:Elastic and viscous constants characterizing viscoelastic rheo
 logy of sea ice samples harvested in the Van Mijen Fjord of Spitsbergen we
 re determined from a set of laboratory and field-based tests with ice core
 s and ice beams (2020-2022). A model of transversely isotropic continuum w
 ith vertical axis of symmetry was chosen to describe properties of columna
 r ice. The elastic constants were calculated from the measurements of natu
 ral frequencies of vertically and horizontally oriented ice beams and meas
 urements of pressure wave speeds in 3 spatial directions. Dependencies of 
 the shear wave speeds and Rayleigh wave speeds from the direction of wave 
 propagation are discussed. Viscous constants of the Burgers model were det
 ermined from the laboratory tests on stress relaxation and loading-unloadi
 ng tests performed with ice cores at different temperatures. The Burgers m
 odel was used for the simulation of ice deformations and ice stresses meas
 ured in full-scale experiments on long-term loading of floating sea ice in
  the Van Mijen Fjord. The ice was loaded by the bandwagon with weight 4.5 
 t during 2 h in 2021 and 30 h in 2022. Numerical simulations were performe
 d with Comsol Multiphysics FE software. Simulations results describe well 
 measured dependencies of ice stresses and displacements from the time. At 
 the same time\, it was discovered that ice temperature changes caused by w
 eather conditions influence ice pressure significantly over the measuremen
 t time. The Burgers model was also used for the calculation of surface wav
 e damping in ice covered ocean regions. In combination with energy dissipa
 tion in under-ice boundary layer the model describe well wave damping in a
  wide frequency range. Laboratory experiments in HSVA ice tank and field m
 easurements in the Ice Fjord of Spitsbergen were used to validate the mode
 l of wave damping. &nbsp\;&nbsp\;&nbsp\;&nbsp\;&nbsp\;&nbsp\;&nbsp\;
LOCATION:Seminar Room 1\, Newton Institute
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