Author(s): Vegard Aksnes
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Keywords: No Keywords
Abstract: Model tests of a moored ship with a simplified geometry have been performed in level ice. The model was only able to move in surge, and was moored with a linear spring setup. Two different natural periods were achieved by using springs with different stiffness characteristics. Two different ice drift speeds were used. Different dynamic properties of the model as well as the drifting ice could therefore be studied. The model was also tested in a fixed configuration to enable a comparison between fixed and moored setups. The dynamic response of the model was investigated and effects from variations in the mooring stiffness and ice drift speed were identified and analysed. It was seen that the largest mean mooring force and the largest surge oscillations occurred for the lowest mooring stiffness at the lowest speed, probably caused by stick-slip friction along the sides of the model. The mooring force for the stiff springs and the fixed configuration both increased with ice drift speed. The con figuration with stiff springs experienced lowest forces. Ice forces on the waterline of the bow increased with ice drift speed and were larger for the soft configuration than for the stiff one.
Year: 2010