Multiobjective optimization of composite risers

Abstract

Use of fiber-reinforced laminated composites has proved itself as a valuable option in the manufacturing of risers, particularly for deepwater applications, a scenario where its lightweight related properties and good fatigue resistance are most needed. In addition, its use allows these structures to be tailored to meet specific manufacturing, safety, and stability criteria. This paper proposes an optimization model to composite risers in a free-hanging catenary configuration that considers multiple load cases and two objective functions. The optimization is carried out using a modified version of the Nondominated Sorting Genetic Algorithm II (NSGA-II). The riser structural analysis is performed by an inextensible cable model that accounts for the vertical static loads, floater offset and current loads in a fast and efficient way. The proposed algorithm is validated using a benchmark problem and applied to obtain the Pareto Front of a composite riser.