FPSO pipeline stress analysis
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Has anyone done stress analysis of pipelines on FPSOs? I would like to ask how hull sagging and hogging deformations of the ship are taken into account in the CII model during pipeline stress analysis on FPSOs
This involves calculations of the vessel’s deformation that occur during loading/unloading as well as due to changes in sea conditions. In previous projects, the structural positions of the vessel were assigned coordinates; at each specific structural coordinate, there were different amounts of hogging and sagging displacement. The design positions of the pipe supports were then determined using corresponding coordinate systems, thereby allowing for the determination of the structural deformation displacements. In CII, the type of pipe support at a given point is linked to the structural deformation displacements through CNodes. In FPSO projects, the most challenging aspect is likely the design of the entire hull structure; the stress in the piping systems and the design of the supports are both adjusted to accommodate the displacements of these structures
My understanding is also that the owner’s documents should provide the sagging and hogging displacements at different coordinates. But the documents provided to me by the owner only show the vertical displacement along the length of the hull, as well as the sagging and hogging displacements at coordinates along the cross-section of the hull; they do not provide the sagging and hogging displacements at all coordinates. Therefore, I’m not sure how to apply the loads.