Wave Loading Uncertainties and Structural Fatigue Reliability Researches for Semi-Submersible

摘要

Uncertainties of wave loading have large proportions in analysis of structural fatigue strength for ocean platform.The assessing methods and formulas are built for wave spectrum, sea wave height, wave loading transfer function, cross-zero period, sea state occurring possibility and wave direction due to investigate the uncertainties of wave loading during calculating fatigue loading.Meanwhile,wave loading model trial is taken for assessing the uncertainty of wave loading transfer function.The correcting formulas of significant wave height and mean cross-zero period in Northwest Pacific are regressed statistically after specially calculating the sea states in Northwest Pacific and South China Sea.Furthermore the influence factors of difference season sea states and principle of wave direction distribution to wave loading and fatigue life of semi-submersible are investigated.Finally, the fatigue reliability index of typical structures for semi-submersible is researched on the basis of uncertainties of wave loading and the other uncertainties during structural fatigue analysis.