Dissertation in the field of marine technology and ice mechanics, Rüdiger U. Franz von Bock und Polach, Dipl.-Ing.
New numerical model for the model ice behaviour of the Aalto Ice Tank.
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The public examination of the doctoral dissertation of Rüdiger Ulrich Franz von Bock und Polach, Dipl.-Ing., will be held on 10 June 2016 at 12.00 at the Aalto University School of Engineering. The title of the dissertation is The Mechanical Behavior of Model-Scale Ice: Experiments, Numerical Modeling and Scalability. The field of the dissertation is marine technology and ice mechanics.
The research presented in the thesis investigates the mechanical behaviour of model-scale ice, which is produced in the Aalto Ice Tank. Model-scale ice is a surrogate material in which ships are tested in a smaller scale to assess the performance of the actual ship in sea ice. Ships predominantly break the ice by bending it downwards until it breaks.
The subject of the thesis is the experimental analysis of the mechanical behaviour in tension, compression and bending, which are supported by numerical models. On this basis its deformation behaviour is compared to sea ice.
It is found that the model-scale ice responds in elastic-plastic manner and that properties vary significantly through its thickness, which differs significantly from sea ice. This provides an explanation for variations in results obtained by different experimental procedures. This is an oddity that has been encountered, but not solved by other researchers over the past 30 years.
Consequently, this shows that some of the applied standard measurements are not suitable to assess the stiffness of the ice and might give a wrong impression about the mechanical constitution. In this context it is also suggested to reconsider the definition of applied scaling laws.
The qualitative knowledge of the evaluated properties allow in future to design ice model tests and analyse their results in an improved way as the model ice behaviour is better understood. Furthermore, it is indicated that future research is necessary to continuously improve the knowledge of the model-scale ice.
Opponents: Professor Rocky Taylor, Memorial University, Canada, Professor Lennart Josefson, Chalmers University of Technology, Sweden
Supervisor: Professor Gary Marquis, Aalto University, School of Engineering
Electronic dissertation thesis: https://aaltodoc.aalto.fi/handle/123456789/20380
Contact: Rüdiger Ulrich Franz von Bock und Polach, ruediger.vonbock@aalto.fi