TLP平台垂荡运动对立管疲劳寿命的影响

摘要

针对海洋平台与立管接头的非线性特征,就TLP平台的一阶与二阶垂荡运动及其对立管上端点耦合产生位移,在考虑平均应力影响的基础上,基于DNV,ABS与UK等船级社规范提供的S-N曲线,讨论立管的疲劳问题.采用Goodman模型与Gerber模型进行有效循环应力分析与对比.从4种非线性接头对于立管上端点的动应力影响来看,接头节点的非线性特征,对立管应力影响较大.考虑平均应力影响,从2个模型(Goodman和Gerber)的比较来看,Goodman模型考虑平均应力影响相对保守；从平台的一阶、二阶垂荡对立管上端点的影响来看,一阶垂荡过程中,最大应力点在触地点,二阶垂荡最大应力点为立管上端点；从疲劳损失程度来看,二阶垂荡运动对疲劳寿命影响较大；从3个船级社的S-N曲线来看,DNV的S-N曲线偏于保守,ABS的其次,UK的S-N曲线得出的疲劳寿命最长.%This paper presents riser fatigue life analysis under TLP platform heave motion. The main influence parameters considered are: the first and second order heave of TLP, the nonlinear character of joint,mean stress and different S-N curves. The mean stress is considered under the Goodman and Gerber model. S-N curves are provided by ABS,DNV and UK. Numerical modeling anslysis has shown that the riser dynamic stress of riser are directly correlated with nonlinear character of joint; the influence of mean stress is low under the Goodman model; the max stress of riser appears at the TDP ( touchdown point ) under first order excitation, and appears at TP ( top point) under second order excitation; the life is longest under UKDOE' s S-N curve,the ABS is medium,and DNV is the shortest.