Experience from offshore oil and gas installations shown the presence of non-uniform corrosion attacks (pitting), wear and premature environmental fatigue failure of mooring chains despite the large safety factors used in the industry standards. The impact of ocean environment, as well as the effects of dynamic loads and static "mean" loading on fatigue damage in mooring chains, need comprehensive understanding to improve predictive lifetime consideration. This is especially crucial in the context of diverse offshore floating structures and their specific conditions. For floating wind turbines, when a turbine controller is involved, static and dynamic load on the mooring change in a very different pattern with the sea-state severity, and it is unclear how this affects the fatigue damage.
Objective:
Develop method to improve mooring system integrity (especially lifetime estimates) by accounting for the degradation mechanisms in mooring chains, the operational history, and results from monitoring and inspection. Apply the results to "classical" offshore structures and floating wind turbines.
