Short-term statistics of ice loads on ship bow frames in floe ice fields

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-11
Major/Subject
Mcode
Degree programme
Language
en
Pages
28
Series
Marine Structures, Volume 80
Abstract
Ship operation and ice loading in floe ice fields have received considerable interest during recent years. There have been several numerical simulators developed by different institutes which can simulate ship navigation through floe ice fields and estimate ship performance and local ice loads. However, public data obtained from full-scale measurement covering comprehensively ship performance and ice loads under various ice thicknesses, concentrations and floe sizes are rare. The 2018/19 Antarctic voyage of the Polar Supply and Research Vessel (PSRV) S.A. Agulhas II gathered considerable data of the ship in floe ice fields under various thicknesses, concentrations, and floe sizes. The aim of this paper is to carry out statistical analysis to seek suitable probability distributions which adequately fit the measured ice load and therefore suitable to be used as parent distributions for long-term estimation. For this aim, three categories of probability distributions, namely standard distributions, truncated distributions and mixture distributions are tested. It is found that truncated distributions can fit the load data better than standard distributions bounded at the threshold. In addition, mixture distributions are shown to have promising features, which fit the data well and are able to separate distribution components. Subsequentially, the well-performed distributions are used as parent distributions to make long-term load estimations. The estimation results demonstrate that long-term estimations are sensitive to the selection of parent distribution, which addresses the importance of finding correct distribution to model short-term ice loads. The data of ten selected cases will be published for the use of other researchers.
Description
Funding Information: This project has received funding from the Lloyd's Register Foundation, a charitable foundation, 563 helping to protect life and property by supporting engineering-related education, public engagement and the application of research www.lrfoundation.org.uk. We also than Andrei Sandru for providing the processed images; and Christof M. van Zijl, James-John Matthee and Annie Bekker from Stellenbosch University, who provide enormous helps on visual observation of ice condition during the SANAP 2018/2019 and Weddell Sea Expedition 2019. Funding Information: This project has received funding from the Lloyd's Register Foundation , a charitable foundation, 563 helping to protect life and property by supporting engineering-related education, public engagement and the application of research www.lrfoundation.org.uk . We also than Andrei Sandru for providing the processed images; and Christof M. van Zijl, James-John Matthee and Annie Bekker from Stellenbosch University, who provide enormous helps on visual observation of ice condition during the SANAP 2018/2019 and Weddell Sea Expedition 2019. Publisher Copyright: © The Authors
Keywords
Floe ice field, Full-scale measurement, Ice load statistics, Mixture distribution, Statistical inference, Truncated distribution
Other note
Citation
Li , F , Lu , L , Suominen , M & Kujala , P 2021 , ' Short-term statistics of ice loads on ship bow frames in floe ice fields : Full-scale measurements in the Antarctic ocean ' , Marine Structures , vol. 80 , 103049 . https://doi.org/10.1016/j.marstruc.2021.103049