FPSO上部模块管道疲劳分析方法的应用

A METHOD FOR FATIGUE ANALYSIS OF TOPSIDES PIPING IN FPSO

在海浪和海风作用下,FPSO会发生中垂/中拱、摇摆以及颠簸起伏,其上部结构将获得加速度并且产生变形,船体的变形会通过生根在结构的支撑带动管道产生位移,因此设计寿命内FPSO上部模块管道是否会发生疲劳破坏需要重点评估。通过某项目实例,结合ASME B31.3和DNV规范,介绍了FPSO上部模块管道疲劳分析的方法。对于波浪运动产生的高周疲劳破坏,该方法能够将不同浪高对管道破坏程度不同的因素考虑在内,摒弃了疲劳极限分析方法过于保守的缺点,更为真实的反应了管道疲劳累积的程度,工程设计上可以采用该方法对FPSO上部模块管道疲劳破坏进行分析和评估。

FPSO will be subject to sagging/hogging,pitch,roll and heave because of wind load and wave motion.Piping on the module structure will be subject to acceleration loads and deflections from FPSO motions.The fatigue failure of topsides piping in design life should be evaluated.In this paper,a method for fatigue analysis of topsides piping is introduced combined with ASME Code B31.3and DNV.For high-cycles fatigue failure caused by wave motion,the different damage degree caused by different magnitude of wave can be taken into account.Overcoming the shortcomings of the conservative fatigue limit analysis method,this method can more accurately reflect the accumulated fatigue extent of the piping and be applied in the fatigue failure analysis of topsides piping in FPSO.