09:00 to 09:50 Registration 09:50 to 10:00 Welcome from David Abrahams (INI Director) 10:00 to 11:00 Erland Schulson (Dartmouth College)Friction of Sea Ice Friction of sea ice plays a fundamental role in a variety of geophysical and engineering scenarios. Examples include ridging and rafting, ice-induced loads on offshore structures and the physics of brittle compressive failure. In this paper attention is focused on the characteristics of static friction and frictional sliding of ice upon ice at velocities of around 0.1 m s-1 (~10 km/day) and lower, at homologous temperatures greater than around Th =0.85 (>-40 o C). The coefficients of both static and kinetic friction are described and then discussed in terms of the underlying physical processes. At root is creep deformation of asperities. Creep leads to an increase in contact area and thus to an increase in the coefficient of static friction with increasing time under load. Creep leads also to an increase in the coefficient of kinetic friction with increasing velocity at lower speeds. At higher speeds, localized melting of asperities sets in, via frictional heating, and this leads to a decrease in the kinetic coefficient with increasing velocity. Modeling indicates that the velocity that marks the transition scales as $V_t \propto a \Delta T^2$ where $a$ denotes asperity size and $\Delta T$, the difference in temperature between the melting point and the body of ice. Implications for sea ice mechanics are discussed. INI 1 11:00 to 11:30 Morning Coffee 11:30 to 12:30 Paul Verlaan (Shell Global Solutions)Ice-structure interaction in the Sakhalin-II (Sea of Okhotsk) and Kashagan (NE Caspian) project In this presentation, it will be described which approach was taken to specify global and local ice loads for the structures in two different oil & gas projects in sub-Artic areas: the Sakhalin II project in the Sea of Okhotsk and the Kashagan project in NE Caspian Sea. In both projects, the approach was a combination of deterministic methods described in the different design codes, probabilistic methods and scale tests in an ice tank.  For the Sakhalin II project, global ice loads were particularly relevant for the design of the two multi-legged platforms (Piltun-B and Lunskoye-A). In contrast, in the NE Caspian, an accurate determination of the global ice loads was mainly relevant for design of the ice protection barriers rather than for design of the islands itself. Instead, much more attention was paid to specifying the risk of ice encroachment onto the islands.  In all cases, it was found that the limited amount of ice data often resulted in a conservative design with still considerable uncertainties in the design loads. INI 1 12:30 to 13:30 Lunch @ Wolfson Court 13:30 to 14:30 David Cole (U.S. Army Research Laboratory)Structure-property relationships for sea ice: Modeling and experimental validation This talk addresses the constitutive behavior of sea ice, with a focus on the relationships between measurable physical properties and the elastic, anelastic and viscous components of strain. To accommodate attendees with a limited knowledge of sea ice, the presentation includes a brief overview of the microstructure and flaw structure of naturally occurring sea ice. Some attention is paid to the structure and mechanics of columnar and granular freshwater ice for completeness. The components of strain are quantified in terms of crystallographic characteristics (primarily c-axis orientation), dislocation density for the inelastic components, and temperature. The mechanisms of anelastic strain (e.g., time-dependent but recoverable) are associated with basal dislocation glide and grain boundary sliding. Viscous straining is quantified in terms of drag-controlled dislocation glide on the basal planes. It is shown that dislocation density exerts an overwhelming influence on the constitutive behavior of sea ice both at the scale of laboratory experiments (0.1 m) and in-situ experiments ( ≤ 30 m). Recent efforts to account for certain high temperature effects and differences between in-situ vs. in-vitro constitutive behavior of sea ice are described and the associated modifications to the published constitutive model are discussed. An analysis of existing cyclic loading and creep experiments makes it possible to identify the physical basis for the apparent increase in activation energy of inelastic behavior with proximity to the melting point. Additionally, brine drainage from specimens harvested for laboratory experiments is shown to cause a major discrepancy between the in-situ elastic response of warm sea ice vs. that found in laboratory experiments. INI 1 14:30 to 15:30 Andrei Metrikine (Technische Universiteit Delft); (Norwegian University of Science and Technology); Hayo Hendrikse (Technische Universiteit Delft)Ice-induced vibrations of offshore structures: physics of the process, modelling and remaining challenges INI 1 15:30 to 16:00 Afternoon Tea 16:00 to 17:00 Aleksey Marchenko (University Centre in Svalbard (UNIS))Thermo-mechanical loads of sea ice on structures Thermally induced loads of ice on structures and shorelines occur due to thermal deformations of confined ice. Thermally induced stresses in the ice follow the temperature changes, depend on the coefficient of thermal expansion of ice and are reduced due to the relaxation. Temperature changes in sea ice occur due to conductive heat transfer characterized by specific heat capacity and thermal conductivity of ice and due to the advection of liquid brine depending on sea ice permeability. Coefficient of sea ice thermal expansion depends on the amount of liquid brine trapped in closed packets inside the ice. Proportion between the amounts of liquid brines trapped in closed packets and existing in permeable channels depends on the ice temperature and salinity. Relaxation and creep rheology of sea ice also depends on the temperature and ice structure.Thermo-mechanical model of saline ice taking into account above described properties was recently formulated by Marchenko and Lishman (2017). The dependence of the coefficient of thermal expansion of saline ice from the temperature was reconstructed from the laboratory experiments. In the present work the model equations are used to estimate and compare the heat fluxes and thermal deformation of sea ice caused by the heat conduction and brine advection. Further the model is used for numerical simulations of ice loads on the cofferdam of coal quay in Kapp Amsterdam, Spitsbergen.Field observations and records of the loads from sea ice confined inside the cofferdam were performed since 2013 (Marchenko et al, 2013; Wrangborg et al, 2015). Sea ice temperature was measured synchronously with the loads over entire ice thickness using thermistor string frozen into the ice. It was discovered that sea water brine migrates through the confined ice with thickness of 2-3 m under the influence of the water overpressure below the ice caused by semidiurnal tide. Horizontal ice loads on the cofferdam walls are also changed according to the semidiurnal cycle. Thermo-mechanical model of saline ice is used in numerical simulations of the observed phenomena by finite element method realized in Comsol Multiphysics software. INI 1 17:00 to 18:00 Welcome Wine Reception at INI