深水FPSO总纵强度分析和结构设计

Longitudinal Strength Analysis and Structural Design of Deep Water FPSO

深水浮式生产储卸油装置(FPSO)船体为超肥大线型,远洋拖航自存和在位作业满载极端环境工况是FPSO船体设计的控制性工况。基于GL ND《海上拖航指南》和BV船级社规范,优化确定FPSO远洋拖航自存工况的吃水。基于远洋拖航航线和作业海域的环境条件,应用DNV SESAM软件计算FPSO船体波浪载荷和运动加速度,为船体、上部模块、管廊模块和主甲板管道支架设计提供基础数据。FPSO油舱段采用“干式安全带”保护设计理念,减轻了船体结构腐蚀。应用BV VeriSTAR Hull软件分析油舱段船体结构强度,得到船体的应力水平、应力分布和变形。在中间货油舱内设置横撑杆,提高了船体横框架强度和刚度,降低了主甲板强横梁、船底肋板和纵舱壁垂直桁的尺寸,减轻了船体自重。基于累积损伤的简化疲劳分析方法,应用DNV SESAM软件分析FPSO船体结构疲劳,综合考虑了拖航、海上安装和在位作业工况,得到FPSO船体关键结构处的疲劳寿命。

The deep water FPSO hull is designed as an ultra-fat lines shape.The ocean towing survival condition and on-site full load extreme environmental condition are the critical conditions of FPSO hull design.Based on GL ND Guidelines for Marine Transportations and BV Classification Society rules,FPSO ocean towing survival condition draft was optimized and determined.Based on the environmental conditions of ocean towing route and operation sea area,the wave load and motion acceleration of FPSO hull were calculated by DNV SESAM,providing basic data for the design of hull,topside module,pipe rack module and main deck pipe support.FPSO oil tank section adopts the protection design concept of Dry Safety Belt,which reduces hull structure corrosion.BV VeriSTAR Hull software was used to analyze the structural strength of the oil tank section,and the stress level,stress distribution and deformation of hull were obtained.The transverse braces were set in the middle cargo oil tanks,which improves the strength and stiffness of the transverse frame of hull,reduces the size of main deck beam,bottom floor plate and vertical girder of longitudinal bulkhead,so as to reduce the hull weight.Based on simplified fatigue analysis method of cumulative damage,the fatigue of FPSO hull structure was analyzed by DNV SESAM,and the fatigue life of key structure of FPSO hull was obtained by comprehensively considering towing,offshore installation and on-site operation conditions.