The estimation of stress range distribution due to wide banded random loading obtained by rain-flow counting method

Structures installed on offshore field continuously experience wide-banded random loadings such as the combination of long and short period wave loadings, and the interaction between mooring line/riser tensioning and hull structure motion. Those kinds of loadings usually cause multi-peak response spectrum which consequently influence the accumulation of fatigue damage. Most combination models to estimate the fatigue damage on the complex loadings have been proposed in the form of a correction factor that correlates the fatigue damage from narrow-band assumption with the reference fatigue damage from rain-flow counting method. It is well-known that excellent prediction of the stress range distribution can lead precise fatigue damage estimation. Therefore, this study will suggest a model for new stress range distribution based on the rain-flow counting method and fatigue damage calculated from the new model will be compared with ones from different existing models.