A CONCEPT DESIGN FOR A MESO-SCALE FLOATER TO MEASURE DOWNWARD BENDING FAILURE ICE LOADS

摘要

When designing a floating structure for regions where sea ice may occur, it is imperative to have an accurate prediction of the ice loads. Currently there is a big difference in predicted forces between several prediction methods. There is little full-scale load data to verify existing methods. Furthermore, it is not fully clear how well small-scale ice tank experiments can be scaled to full-scale. Force measurements on a meso-scale structure could bridge the gap between small-scale measurements and full-scale data. Results could be used to verify existing load models and develop new ones. This paper presents a concept design for a moored omnidirectional floating buoy with downward sloping sides to measure ice bending failure loads in field conditions. A numerical ice-buoy model is developed to optimise the design and to examine buoy behaviour when loaded by ice. The results show that for a shallow draft design a minimum waterline diameter of 8 m is needed to have ice bending failure up to an ice thickness of 0.6 m. In thicker ice, the buoy will incline too much and the ice will no longer fail in bending. To ensure the safety of the buoy design, a load limiting mechanics based on submersion of the buoy is proposed. This can limit the ice loads in ice thicker than 0.6 m.