MSc thesis project 2019 on the Division of Marine Technology, Department of Mechanics and Maritime Sciences, Chalmers University of Technology

2018-09-16/JR

Numerical models of sea ice materials

Background and motivation Sea ice is a fascinating material. It is a crystalline material whose properties depend on e.g. temperature, salinity of the sea water, weather conditions when the ice structure was formed, and its age. Global shipping seeks for the opportunity to use the North-East Arctic route more frequently in the future since the distance to Asia from Europe is significantly shorter. One of the main issues is the concern for ship safety when the ships face different types of ice material. Do the ships have enough safety margins against local failure (buckling, hull fracture) or even global loads? The majority of the ships which will traffic this route will be able to cross without ice-breaker assistance during the Arctic summer months. Nevertheless, we need more knowledge about ice as a material and how it can be modelled numerically and used in finite element (FE) simulations to assess a ship structure’s response due to global and local ice loads. Objectives and goals of the project Classification societies have developed rules for ships operating in ice. These rules are often based on quasi-static assumptions which today have started to be questioned by among others the ISSC committés. Large number of scientific papers can be found in the literature how ice as a material can be modelled and possibly be included in advanced FE simulations of ice-structure interaction. Some of these models are probably useful, but most of them are not. The main objective of this thesis project is to present: (i) a thorough literature study which starts with class rules, polar codes and their assumptions in ship design, (ii) followed by a thorough review of literature where various ice models suitable for FE analysis have been presented. If time allows for in the project, it would be advantageous to compare some of the most promising ice models either using an own developed Matlab code in this project, or, using the commercial software ABAQUS/Explicit. Methods and tools The tools to be used are first of all literature study in databases, Word and Excel. Matlab or ABAUQS/Explicit will be used if some ice models will be compared in an ice-structure response analysis. The MSc thesis project should incorporate (at least) the following tasks: • Literature study on the topic (see above). • Collecting, categorisation, understanding and describing different approaches and models how to

model ice in novel ice-structure interaction analysis. It will be important to categorize how ice is deformed, fractured or crushed and which conditions and properties that govern these “failure modes”.

• (If there is time) Compare a number of ice models in structural response analyses/simulations. Contact person (examiner and supervisor at Chalmers): Professor Jonas Ringsberg (Jonas.Ringsberg@chalmers.se)