Sea states effects on fatigue damage of large ship prone to springing effect
【Abstract】[Objectives] This paper aims to study the fatigue damage problem of large ships prone to the springing effect. [Methods] The tested fatigue damage of two-generation 400 000 DWT very large ore carriers (VLOCs) is compared by the ship model test method, and the relationships of sea states and fatigue under the springing of hull girders are analyzed. According to the recursion method, a classical sea state is selected from a series of model test sea states. [Results] The results show that the fatigue damage magnification effect has trend relationships with significant wave height and encounter period. The concept of “dominant sea state” is proposed by the inductive recursion method, and the formula of the fatigue damage magnification factor is improved. The springing effect varies significantly according to different sea states, and the fatigue damage magnification effect of wave-induced loads increases very rapidly as significant wave height and encounter period decrease. [Conclusions] Replacing multiple typical sea states with a dominant sea state could allow a relatively accurate fatigue damage magnification factor to be ascertained rapidly. As such, this paper can provide references during the initial design period.
【Keywords】 ship structure; springing; fatigue; ship model test;
(Translated by HAN R)
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