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    Item type:Publication, Access status: without files ,
    Ice trails with “Le Commandant Charcot” for load assessment
    (Lulea University of Technology, 2025-07)
    von Bock und Polach, Rüdiger Ulrich Franz
    ;
    Kaplan, Ihsan
    ;
    Kubiczek, Jan Manuel
    ;
    Haas, Christian
    The Arctic Ocean is in a process of significant changes, which also raises the interest in exploring these changes. This also concerns the performance of ships and how different operational profiles together with climate change are affecting current and future designs. This paper presents ice trials with a PC2 ice classed ship during a Trans-Arctic voyage, where continuously data such as ice thickness and accelerations are measured. From these data the number of ice impacts is determined which is used in a probabilistic extreme ice load assessment. The probabilistic ice pressures are compared with the design pressures from the Polar Ice Classes. The results indicate a significant loading of the structure with a potential to exceed Ice Class values. The analysis and results contain uncertainties, as the applied state of the art needs to be updated with new measurements and data accounting for climate change. A detailed analysis during one ice trail with constant power indicated that ridges contribute significantly to the number of impacts, while recent research on Arctic survey indicates that the ice surface becomes smoother and the number of ridges reduce.
    Publicationtype: Conference Paper
      100
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    Propeller-ice interaction experiments on a scaled S.A. Agulhas II propeller
    (Lulea University of Technology, 2025-07)
    Böhm, Angelo
    ;
    von Bock und Polach, Rüdiger Ulrich Franz
    Between 2011 and 2020, over 16% more incidents of machinery damage and failure were reported in the waters within the Arctic Circle compared to the rest. In addition, Allianz (AGCS) also reported that machinery damages and failures account for more than 45% of all incidents in Arctic waters, which are caused by the exposure of the propulsion system to ice contact. A better understanding of the propeller-ice interaction process would allow a more efficient propeller design and a safer operation in ice-covered waters. However, full-scale measurements of propeller-ice loads are unique. In addition, propeller-ice loads determined in model tanks are hard to transfer to full scale due to the model ice properties and the large scaling of the propeller. Moreover, holistic propeller-ice simulations have yet to be created, capturing the complex ice failure and representing realistic loads. This paper presents propeller-ice interaction experiments on the propeller of S.A. Agulhas II on a scale of 1:3. The experiments focus on contact milling and impact loads. The test matrix consists of different interaction velocities up to 4 m/s using a drop-tower, cylindrical ice specimen with diameters up to 200 mm, and three different contact conditions from milling loads to impact loads. The specimens consist of granular freshwater ice with high uniaxial strength, and the reports of the measured interaction force and the strains measured on the propeller should provide valuable information for future simulations of the propeller-ice interaction process.
    Publicationtype: Conference Paper
      39
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    Parameter-based generator for ice floe fields
    (Lulea University of Technology, 2025-07)
    Sapp, Lina
    ;
    von Bock und Polach, Rüdiger Ulrich Franz
    With decreasing ice thickness and ice extension in summer, shipping in and close to ice-covered areas and the marginal ice zone are of raising interest. To determine the exact forces due to the icebreaking and to enable a more precise and less over dimensioned design of ice-going vessels, models can be a helpful tool. To use these models to simulate the icebreaking process, the ice has to be modelled as well. This work presents a new randomized approach for the generation of ice floe fields based on common simple ice observation parameters and reflecting the real ice floe arrangement: The ice floe field is modified by constrained optimization after the ice floes are placed randomly. The generated ice floe fields are evaluated for different parameter sets, to determine the influence and sensitivity of the different ice observation parameters. The filling of the parameter space depending on the number of generated floe fields per parameter set is estimated. Furthermore, suggestions on how to use these floe fields are given.
    Publicationtype: Conference Paper
      37