Investigation of long-term extreme mooring tensions by fully coupled dynamic analysis

A numerical model, which has been validated by the experimental data is used to simulate a semi-submersible taut mooring dynamic responses in a specified site of South China Sea. In order to take the random wave elevations into consideration, the short term analysis with different random wave seeds are carried to study the system dynamics. The mooring tension distributions in different significant wave heights and peak periods are fitted by Weibull distributions. Different methods including the global maximum method, peak-over-threshold method and short-term peaks method are applied to investigate the long term extreme mooring tension. The estimated long-term extreme mooring tensions are compared, and the accuracy of these methods are discussed.