结构强度随时间变化的平台结构可靠性分析

海洋平台结构在使用期间由受到各种损伤，使得结构材料强度随服役时间的增加而下降，因为损伤和时间密切相关，所以在讨论损伤对结构强度的影响时，引进了时间变量，分析了４种损伤：即疲劳，凹坑，腐蚀和海生物损伤，推导出时变构件可靠性计算的有关公式，在此基础上，运用改进一阶二次矩法及蒙特卡洛重要抽样法，编制了单个构件可靠性分析程序ＩＳＭ，利用该程序对平台单根管件进行可靠度的计算与分析，结果表明，文中所述的原理和

Reliability Anlysis of Offshore Structures Which Structural Strength Dependent Upon Time

During the life of the offishore structure,its structural strength has been declining due to the various kinds of damages which are related to the time factor. In this paper,four major kinds of damages,including fatigue,dent,corrosion,and marine life,are discussed.The specific formulations to evaluate the damaged structures reliability are derived based on the analysis mentioned above.Furthermore the computer program ISM for analyzing structural reliability is developed by using Advanced First Order Second Moment method and Important Sampling Monte Carlo method.Reliability of a tubular joint and a beam are studied as numerical examples. The results show that the theory and the method given in this paper are reasonable and effective.