This paper develops a numerical method for calculating the repetitive ice breaking pattern and load when a ship advances into a level ice. We focus on the ice bending failure in an ice breaking process in level ice. A circle contact detection technique is adopted to determine the contact point between a ship bow and level ice. The dynamic effect of an ice plate bending is included by using results from fluid-ice interaction FE analysis. The crushing effect is estimated by the simplified formula which considers the geometrical location between the ice edge and ship. The developed method is applied to a straight and oblique initial ice edge. The developed method is able to represent the contact between the ship and the level ice as well as the breaking force.

INTRODUCTION

The bending failure of a floating ice-sheet caused by a ship provides a complicated ice breaking pattern (or the contact conditions) as well as the complicated repetitive ice load. This repetitive ice breaking process due to bending is not well known because of the complexity of the geometry of the broken ice pieces. The ice breaking process consists of two phases:

1. the dynamic bending of ice sheet, and

2. the rotating and sliding of broken ice pieces.

The dynamic bending induces a sudden force peak during the one cycle of the ice breaking. The rotating and sliding phases are important for predicting the resistance force The force due to the rotating and sliding phase of broken ice pieces is smaller than the force peak during bending phase. We focus on the breaking of the ice due to bending and ignore the effect from broken ice pieces. In this paper, it is assumed that the ice breaking force is formed by repeating the bending failure of an ice plate, and ice breaking pattern is created by a lot of broken ice pieces.

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