Author(s): Junji Sawamura
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Keywords: No Keywords
Abstract: This paper calculates ice force distributions along a ship hull when a ship advances into the level ice. Author has developed a numerical simulation to calculate ice force on a ship hull induced by a plate ice breaking and the broken ices submerging when the ship is breaking a level ice. Shipice collisions along the waterline are calculated by contact detection algorithm which is very often used in a 3D computer graphics. The bending failure of a level ice which can be estimated by fluid-structure interaction is treated as the ice breaking force. A rotating and a sliding of the broken ice floes after the plate ice breaking is described by 6DOF rigid body simulation. A contact force and a friction force by the interactions between the ship hull and the broken ice floes are treated as the ice submerging force. The contact force between the ship hull and the broken ice is dealt with an impulsive force. A buoyancy force and a drag force are treated as the hydrodynamic force acting on the broken ice. For simplification, the hydrodynamic forces related to a ship motion are neglected. A ship advances straightforward and turns with a constant speed. The numerical simulations calculate the ice channel with zigzag edge and the ice force distribution along the waterline. The effect of broken ice floes on the ice force distributions are investigated. A broken ice interacts with the ship hull and the ice channel with zigzag edge. The motion of a broken ice, which induces a submerging force has an effect on the ice force distributions. The motion of the broken ice become more complicated when a ship is turning. However, the magnitude of ice submerging force is smaller than ice breaking force. Therefore, ice submerging has smaller influence on the peak force which is related to a structural design and a ship maneuverability. On the other hand, the broken ices significantly interact with the ship hull. The ice submerging has relatively bigger influence on the ice resistance which is important for a ship propulsion.
Year: 2014