| Abstract | When navigating in ice, a ship's propeller experiences extremely high loads due to its interaction with submerged pieces of ice. A model is developed that simulates the process that occurs when an open marine screw propeller and a submerged ice body come into contact. The time simulation predicts the ice contact forces acting on a propeller blade and the motion response of ice. The equations of ice body motion are solved time-stepwise with a numerical integration routine that forms the core of the simulation model. The propeller is treated as a rigid body with constant rotational and translational velocities. The ice body shape is idealized as spherical and changes in mass due to cutting are ignored. A propeller-ice contact model, based primarily on laboratory ice cutting experiments, is developed. Selection simulation model results are presented for propeller-ice interaction events over a systematically varied range of parameters. The results indicate several features important to the propeller-ice cutting process: the operating conditions of the propeller and the size of the ice body are important parameters influencing propeller loading; the propeller-ice contact force depends approximately on the square of the propeller diameter; and the effect of ice motion on the cutting process is to reduce the severity and duration of contact loads compared to cases where the ice cannot move. |
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