| Abstract | Reliable modeling of ship maneuvers in ice is of great value for planning voyages, programming automatic pilot systems, and training ship operators. For applications such as training simulators and automatic pilot systems, the model must be accurate, sufficiently detailed to provide the correct 'feel' to ship response, and numerically efficient to in order to provide results in real time. A new ice-hull interaction model for simulating various ship maneuvers in level ice conditions is presented in this paper. Its simple physical detail and short computation time make it very suitable for real-time simulations. In this model, the icebreaking process was numerically simulated in the time domain. The broken channel made by the ship from arbitrary maneuvers was tracked by a simple house-keeping methodology. A physically based ice-hull interaction algorithm was implemented into the numerical framework to calculate the global ice loads acting on the hull. At each time step, the ice-hull contact zones were computed based on the geometry of the existing ice channel and the ship, and the ice load distribution along the hull was then determined by specifically considering the local ice loading processes along the ice-hull interface. The possibilities of ice flexural, crushing and shear failure were included. Three independent ice force components, i.e., the breaking, buoyancy and clearing forces, representing individual processes identified during a typical ice-hull interaction, were also considered. The ship motion responses were then computed from the integrated forces acting on the hull. The model was benchmarked against measurements from several series of physical model tests that were carried out at the Institute for Ocean Technology. These tests include turning and resistance runs using a captive model mounted on a Planar Motion Mechanism (PMM). Ship motions and ice loads during the maneuvers were measured. This paper presents the numerical model and its validation. The comparison of physical and numerical results provides insight into the ship-ice interaction processes, and the numerical model is shown to be a sound platform for more elaborate simulations. |
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