Fatigue and Fracture of Marine Structures

Fatigue and fracture are important potential failure modes for ships and offshore structures. With regard to fatigue, marine structures are in general designed for finite life, requiring detailed knowledge of fatigue strength of the different parts of the structure. Fracture properties are in particular important for structures that are subjected to large strain, for example pipelines during laying operations, and for structures exposed to arctic temperatures where steel materials may become brittle. The course addresses analysis and design methods for welded structures with respect to fatigue and fracture. Emphasis is placed on providing knowledge of materials characterisation and design principles laid down in the most relevant codes and guidelines for design against fatigue and fracture given by NORSOK, DNV, British Standards Institution and American Society for Materials and Testing (ASTM). The theory is illustrated with exercise problems on realistic structures.

Linear elastic and elastic plastic fracture mechanics, materials characterisation, methods for assessment of defects and cracks in structures, failure assessment diagram. Cyclic loading and fatigue of metals, fracture mechanics analysis of fatigue, cumulative damage, stress corrosion cracking, corrosion fatigue, design rules and practices. The course is directed towards marine structures, although the theory and methods which are taught are used also for design and operation of other types of dynamically loaded structures, such as bridges, cranes, pressure vessels, pipelines, risers, aircraft, rotating machinery etc.

Lectures, exercises, and lab demonstrations. 70% of the exercises, in addition to two projects must be submitted and approved for admission to the final exam. The course is part of an international MSc education and is taught in English.