Design optimization of FPSO Topside Module for InPlace, Lift and Weighing conditions

Abstract

Traditional structural design work involves repeated modeling, which is a tedious and time-consuming activity. To solve such problems, optimization of structural elements by using the UC ratio along with grouping is proposed. In the design of the offshore floating platform, optimization methods find out minimum weight solutions for the structure. However, due to the high diversity of profiles cost raises a lot. By doing the optimization in a grouping by UC ratio technique provides the unique optimal solution. The current study proposes an approach for reliability-based optimal design of FPSO structure. The current study comments on the optimized design of Topside FPSO structural assembly for various load conditions like Production tank pressure loads, Equipment loads, Piping loads, Electrical and Instrumentation load, girder deformation loads, Wind load, etc. Both Normal Operating and Extreme Operating conditions are taken by considering the effects of hull flexibility along with wind and motion-induced accelerations. The analysis and design optimization are performed in the STAAD Pro tool by selecting the least weight as an objective function while obeying the design constraints as per API standards. Optimization performed based upon Utility Check ratio in STAAD Pro tool. With analysis models constructed as described above, module primary structure design can be iteratively “unity-check-optimized”. By implication given method, optimized member unity checks (UCs) translate into optimized weight and hence cost optimization.