No abstract

In recent times, the utilisation of marine composites in tubular structures has grown in popularity. These applications include composite risers and related SURF (subsea umbilicals, risers and flowlines) units. The composite industry has evolved in the development of advanced composites, such as thermoplastic composite pipes (TCP) and hybrid composite structures. However, there are gaps in the understanding of its performance in composite risers, hence the need for this review on the design, hydrodynamics and mechanics of composite risers. The review covers both the structure of the composite production riser (CPR) and its end-fittings for offshore marine applications. It also reviews the mechanical behaviour of composite risers, their microstructure and strength/stress profiles. In principle, designers now have a greater grasp of composite materials. It was concluded that composites differ from standard materials such as steel. Basically, composites have weight savings and a comparative stiffness-to-strength ratio, which are advantageous in marine composites. Also, the offshore sector has grown in response to newer innovations in composite structures such as composite risers, thereby providing new cost-effective techniques. This comprehensive review shows the necessity of optimising existing designs of composite risers. Conclusions drawn portray issues facing composite riser research. Recommendations were made to encourage composite riser developments, including elaboration of necessary standards and specifications.

Following the rising technological advancements on composite marine structures, there is a corresponding surge in the demand for its deployment as ocean engineering applications. The push for exploration activities in deep waters necessitates the need for composite marine structures to reduce structural payload and lessen weights/loads on platform decks. This gain is achieved by its high strength–stiffness modulus and light-in-weight attributes, enabling easier marine/offshore operations. Thus, the development of composite marine risers considers critical composite characteristics to optimize marine risers’ design. Hence, an in-depth study on composite production risers (CPR) is quite pertinent in applying composite materials to deep water applications. Two riser sections of 3 m and 5 m were investigated under a 2030 m water depth environment to minimise structural weight. ANSYS Composites ACP was utilized for the CPR’s finite element model (FEM) under different load conditions. The choice of the material, the fibre orientation, and the lay-up configurations utilised in the modelling technique have been reported. In addition, the behaviour of the composite risers’ layers under four loadings has been investigated under marine conditions. Recommendations were made for the composite tubular structure. Results on stresses and weight savings were obtained from different composite riser configurations. The recommended composite riser design that showed the best performance is AS4/PEEK utilising PEEK liner, however more work is suggested using global design loadings on the CPR.