Spatial and temporal load variations in large-scale ice-structure interaction

• Applicant: Professor Dr. Sören Ehlers
• Subject Area: Mechanics
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280425782

Arctic shipping and operations are increasing in ice-covered waters. However, the spatial and temporal variations in the pressure resulting from the ice-structure interaction are not analysed methodically for a wide range of impact velocities for distinct ice types. To obtain design loads, long-term measurements on board of vessels have been carried out where various parameters remain unknown, such as the prevailing ice conditions causing the load. Therefore, ships transiting in ice-covered waters suffer from structural damages frequently. Consequently, this first stage of the project will carry out large-scale ice-structure interaction experiments in controlled laboratory conditions with interphase pressure measurements and experiments to characterise the basic laboratory ice properties. These experiments will become possible with the 4 MN large-scale test frame located at the applicants institute. Thereby we will be able to carry out ice-structure interaction experiments against rigid and deformable structures. The latter will allow us to identify the influence of the structural stiffness on the spatial and temporal variations in the loading. Furthermore, the ice mechanical properties will be identified with a series of smaller scale measurements, which will also allow for the assessment of the scalability in the load variations. This will further contribute to the understanding of the stochastic nature of the loading histories relevant for design ice loads, because the mechanical ice properties causing a distinct variation in ice load will be known and can consequently be altered methodically. As a result, these experiments shall form the basis of a multi-scale computational simulation environment where this first stage of the project will provide the essential large-scale ice-structure interaction knowledge by measuring basic ice and steel material parameters in combination with the spatial and temporal load variations. Since, currently no material model exists being able to account for the full-scale behaviour of ice resulting in accurate loads, we will hereby provide a basic set of parameters to be used to develop one in stage two of this project. Hence, as a result of the entire project we will seek to develop such multi-scale computational environment to simulate ice-structure interaction numerically.

• DFG Programme: Research Grants