Structural characterization and design optimization of hybrid composite tubes for TLP riser applications

Abstract

Composite materials offer a unique opportunity for offshore applications where high stiffness and light weight are the major design criteria. Deep water drilling and production risers are one area where detailed design studies of potential composite applications are required. This thesis outlines the essential considerations for the analysis and design of structurally and economically efficient layups that may be considered for multiaxial load bearing structures. The work focuses on analytical and experimental characterization of prototype tubes and the development and implementation of an optimization technique to study the design of prototype and full scale components. A progressive failure criteria in the finite element procedure is utilized to accurately capture detailed failure behavior of composite tubes and correlate analytical results with experimental data. Once confidence in the analytical approach is gained and design requirements are established, the developed design optimization methodology is applied to the optimization of a potential riser tube for a tension leg platform (TLP). Further analyses are then used to select a final optimized design and confirm its capabilities.