As a case study, a complete stochastic spectral fatigue analysis of a representative turret-moored FPSO design to be situated in a severe environment has been performed. After a global fatigue screening, three longitudinal-to-web frame connections in the outer shell were chosen for in-depth fatigue analysis. For each connection, fatigue lives were computed and are compared for alternative designs in which the crosssection of the longitudinal stiffener, the profile of the web frame cutout, the presence of brackets, the offset of the web frame stiffener, and the position of the lug plate are varied. This paper comprises Part II, in which the results are presented and discussed.
As a case study, a complete stochastic spectral fatigue analysis of a representative turret-moored FPSO design to be situated in a severe environment has been performed. The representative design is not specific to any existing FPSO currently in service or in the design stage. Global finite element and panel models of the representative design were created, from which global vessel motions, stresses, and deformations were computed. A global fatigue screening was performed that identified the locations likely to be critical for fatigue. Of these locations, three longitudinal-to-web frame connections in the outer shell were chosen for in-depth fatigue analysis. The first connection is at the bottom shell next to the turn-of-the-bilge, the second is at the side shell immediately above the turn-of-the-bilge, and the third is at the side shell near the still-water-line. The chosen connections are situated in a web frame near midship, just aft of the turret area. From the global analysis, intermediate and local sub-models were employed to isolate the chosen connections.
