单点系泊系统将军柱疲劳分析

渤海某FPSO的单点系泊装置固定塔架由导管架、将军柱和上部组块构成,其中将军柱是系泊力的主要承受构件之一,其结构安全至关重要。由于系泊力是典型的交变载荷,作用在结构上会产生疲劳损伤,因此有必要对将军柱进行在位期间的疲劳分析。本文提出一种长期海况下海上固定装置疲劳计算方法,通过AQWA软件建立单点系泊系统的多体耦合水动力模型模型,根据渤海的海况环境资料计算出FPSO运动时域内所受到的的系泊力;基于S-N曲线方法与Miner线性累计损伤理论,通过nCode Designlife疲劳计算软件计算将军柱结构的疲劳寿命和管节点的疲劳损伤;评估结构的疲劳强度,分析易发生疲劳的关键节点位置,并给出增加管节点疲劳寿命的建议及设计方法,为相同类型的海上固定式结构物的结构设计及疲劳分析提供有益的参考及借鉴。

Single point mooring system king post fatigue analysis

The fixed tower of the single point mooring system of a certain FPSO in Bohai consists of a jacket,a king post and a topside.The king post is one of the main bearing members of the mooring force,and its structural safety is essential.Since mooring force is a typical alternating load,it will cause fatigue damage on the structure,so it is necessary to analyze the fatigue of the king post during the in-place.This paper presents a method for calculating the fatigue of offshore fixtures under long-term sea conditions.Multi-body coupled hydrodynamic model model of single point mooring system established by AQWA software,calculate the mooring force in the FPSO motion time domain based on the sea state data of the Bohai Sea;Based on the S-N curve method and Miner linear cumulative damage theory,the nCode software is used to calculate the fatigue life of the king post and the damage of the pipe joint;evaluate the fatigue strength of the structure,analyze the location of key nodes prone to fatigue,and give suggestions and design methods to increase the fatigue life of the pipe joints.It provides a useful reference for the structural design and fatigue analysis of the same type of offshore fixed structures.