| Résumé | Structural risk analysis for a new 172,600 m3 Arctic LNG Carrier was carried out. Finite element software, LS-DYNA, was used for the analysis. Three different iceberg masses were used: 3,320 ton, 6,640 ton and 10,000 ton. Six impact simulations were conducted for the condition where no water was present where the vessel forward speed was ~19.5 kt and the iceberg speed was 5 kt perpendicular to the tracking line of the ship. Impacts were targeted on specific areas of the vessel’s bow section. Bell-shaped icebergs, specified by DSME, and more realistic vase-shaped icebergs, developed by NRC, were used for the simulations. The maximum contact force that was measured was in the 80 - 90 MN range for the 10,000 ton iceberg for either shape. The maximum deflections of the outer and inner hulls for these cases were -263.9 mm and -29.5 mm respectively. Two simulations using the 10,000 ton NRC vase-shaped iceberg and DSME bell-shaped iceberg were conducted where water, and associated hydrodynamics, was included. For these wet-case simulations the vessel speed was ~19.5 kt and the maximum impact force was in the same approximate range as the dry-case simulations. The outer and inner hull deflections for the wet-case simulations were significantly higher than those for the dry case because the deformable hull section was less constrained and consequently more flexible than the actual case corresponding to the dry-case simulations. Ice contact areas and average pressures were determined for seven cases. All of the simulations generated sliding-load impacts. No rupturing/tearing of the outer hull was observed for any case. |
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