张力腿平台拉索的疲劳损伤

目前在分析张力腿平台(TLP)疲劳损伤时,通常限定平台只发生小位移,未考虑不利工况下平台发生有限位移的情况.在分析模型中考虑有限大位移后,会引入多种非线性因素,也会使TLP的动力响应明显不同于小位移情况,因此研究TLP有限位移下非线性波浪载荷引起的疲劳损伤十分重要.首先求得随机海浪作用下TLP拉索应力的时间历程曲线,并采用雨流法对其进行计数得到疲劳载荷谱;然后依据Miner累积损伤模型,求得TLP拉索在不利工况下的疲劳损伤;最后对ISSCTLP平台拉索在某海况下进行了疲劳损伤短期计算,并说明TLP拉索疲劳可靠度的计算方法.

Fatigue damage of the tether of tension leg platform

Most of the existing methods for analyzing fatigue damage of the tether of tension leg platform (TLP) restrict the displacements of TLP to small magnitude, leaving out of the case of account the case of finite displacements in adverse operation state. If finite displacements are considered in the mathematical model, many nonlinear factors will be introduced. And the dynamic responses of TLP are largely different from that of small displacements. Then it is important to study the fatigue damage of the tether induced by nonlinear wave loads in the condition that TLP moves with finite displacements. The stress time histories of the tether in random waves are calculated, and then the rain flow counting method is employed to obtain the fatigue load spectrum. The Miner linear cumulative law model is used to get the fatigue damage of the tether of TLP in adverse operation state. The short-term analysis of fatigue damage of ISSC TLP in certain sea state is performed. The calculate method for the prediction of reliability of the tether is shown.