Characterisation of new-generation dynamic offshore cables

Fatigue analysis is a critical design issue for dynamic cables for use in offshore wind energy systems. The basis for assessment of fatigue damage of such elements is the long-term stress cycle distribution at critical locations caused by long-term environmental loading on the system. The long-term stress cycle distribution requires global dynamic time domain analysis followed by a detailed cross sectional analysis in a spectrum of irregular sea states. Accurate evaluation of local stresses in complex cross-sections subjected to extreme and fatigue loads is very challenging. Industry standard software frameworks, such as Helica, are currently orientated towards offshore oil and gas components and do not feature the required level of accuracy to handle new and innovative dynamic cable designs. This PhD project will address the shortcomings of existing industry software tools by developing a significantly enhanced cross section modelling capability. The resulting validated analysis tools will provide higher levels of confidence when developing new installations, as well as improved efficiency in the resulting designs. The tools will also be of benefit in retrospective analysis and lifecycle assessment of existing cable elements.