Surrogate-assisted optimisation design of composite riser

The risers made out of advanced composite materials would be significantly lighter than their metallic counterparts. In addition, they would also offer better fatigue and corrosion resistance. Their use can lead to increased production capacities, reduced operational costs of existing offshore platforms and the possibility of extraction of oil and gas from greater depths. The use of advanced composite materials also offers the possibility of tailoring composite risers design to meet specific load requirements. In the first phase of this research, the optimisation of the parameters of the composite tubing was attempted through a process of parametric analysis, manual inspection and selection. In the current paper, the optimisation of the composite riser for minimum weight is accomplished through implementation of a more rigorous mathematical optimisation technique. A population-based surrogate-assisted evolutionary algorithm is employed to identify the optimum design. The objective is to achieve the design with minimum structural weight while satisfying critical load cases, both local and global. The approach and the results of the design optimisation of the composite riser are presented. The optimal design results are verified using finite element analysis under local and global design requirements and compared with different design methods.