Local pressures for ships in ice

• Published in: Marine Structures
• Main Authors: Shamaei, Farhang, Bergström, Martin, Li, Fang, Taylor, Rocky, Kujala, Pentti
• Other Authors: Department of Mechanical Engineering, Marine Technology, Memorial University of Newfoundland, Aalto-yliopisto, Aalto University
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Ltd. 2020
• Subjects: Arctic shipping; Arctic ships; Event-maximum method; Ice loads; Ice pressure; Ship design tools; Antarctic; Antarctic Ocean; Arctic; Barents Sea; Bering Sea; Kara Sea; The Antarctic; Antarc*; Beaufort Sea; Icebreaker
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/45833; https://doi.org/10.1016/j.marstruc.2020.102822

| openaire: EC/H2020/723526/EU//SEDNA Ships operating in ice might be exposed to significant ice loading. Using a probabilistic semi-empirical method known as the event-maximum method, the long-term maximum level of ice loading on a ship can be estimated based on parent distributions of short-term full-scale ice load measurements. The event-maximum method is used to model the relationship between extreme local ice pressures and impact area by estimating parameters corresponding to the inverse slope (α) and intercept (x0) for the line of best fit for the tail of ranked peak pressure data versus the natural logarithm of the Weibull plotting position. These best-fit lines are assumed to follow an exponential distribution and associated α and x0 values are produced for different local design areas. This allows for the determination of α-area curves, which reflects the relationship between ice pressure and the local design area. Previous studies have determined α-area curves for different geographical areas such as the Beaufort Sea and South Bering Sea, representing different ice types including both first-year and multi-year ice. In this study, two separate sets of full-scale ice load measurements having been considered, namely measurements from the Kara Sea and the Barents Sea, as well as measurements from the Antarctic Ocean. Using these two datasets, two new α-area curves have been generated that represent among other operating areas (the Kara Sea and the Barents Sea), operating modes (icebreaker assisted operation) and impact areas (aft shoulder) not covered by other curves. Earlier formulations of the event-maximum method are based on local design areas in which the width and height of areas are defined by the size of instrumented rectangular panel areas (or combinations of those areas) on the bow of the vessel from which the data were collected. In that approach, ice thickness is not directly considered since the height of individual panels is based on the dimensions of instrumented areas and moreover, ...