Numerical simulation of the ice-structure interaction in LS-DYNA
Design of offshore structures in Arctic waters is strongly dependent on local and global ice loads. These loadings are, in general, contact forces transmitted to the structures during interaction with ice floes, ice ridges or icebergs. The prediction of ice forces on structures relies heavily on a thorough understanding of mechanical behavior of sea ice as well as on in-depth knowledge of interaction between ice features and structures. Sloping, or conical shaped structures are commonly used structures for arctic oil and gas exploration and production due to the fact that these structural shapes induce ice bending failure on the structure slope, so that the horizontal ice loads on the structure can be reduced compared to a crushing type of failure, which occurs when ice floes interacting with vertical structures. As an ice sheet advances toward a conical or sloping structure, the ice load increases until the drifting ice sheet fails by bending and forms ice blocks. Following the failure of the ice cover, the failed ice blocks are pushed up the sloping structure or forms ice rubble in front of the structure. Predicting the correct failure modes (crushing, bending, and splitting or combined modes of failure) is desirable as well as the global force on the structure. However, this is not straightforward due to the complexity of the mechanical behavior of ice. It is facing some challenges such as, anisotropy (ice can be considered as a transversally isotropic material), inhomogeneity, and strain rate and pressure dependent response. Some of these key behaviors are considered on this study as a preliminary start for the further investigations as a part of the ColdTech project.
Session3_Paper3.pdf
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