自升式钻井平台桩腿疲劳分析

Fatigue Analysis of Jack-up＇s Leg

利用DNV的SESAM软件分析自升式钻井平台桩腿在波浪循环载荷作用下的疲劳寿命。采用随机方法分析桩腿的疲劳寿命，首先利用WAJAC软件根据线性化后的Morison方程在频域内得到桩腿的波浪响应函数RAO，然后利用SESTRA软件进行动力分析得到桩腿的应力响应函数，最后在FRAMEWORK软件中读取桩腿的应力响应函数，并输入波浪散布图，采用的波浪谱，以及S-N曲线、SCF值等疲劳参数进行疲劳分析。计算结果表明，该自升式平台桩腿的疲劳寿命满足船级社的要求，所采用的方法正确、有效，可以为自升式钻井平台桩腿的基本设计提供依据。

A fatigue analysis about jack-up＇s leg subjected to wave loads is done with SESAM software of DNV. Stochastic method is adopted to investigate the fatigue life of the leg. First, based on linear Morison equation in frequency domain, the wave load response function of the leg is obtained using WAJAC program. Secondly, the stress response function of the leg based on FEM of structural dynamic analysis is obtained using SESTRA program. Thirdly, the stress response function is read by Framework program and the wave scatter, wave spectrum, S-N curves, SCFs, etc are input into the program to do fatigue analysis. The results demonstrate that the fatigue life of the jack-up＇s leg satisfies the classification＇s requirement, and the present method is right and effective, and can be offered as a foundational design basis of the jack-up＇s leg.