Composites offer dramatically high stiffness to weight and strength to weight ratios which make them very desirable for use in offshore structures in deep water. In addition to high specific strength, composites offer the unique feature of being tailorable to the design. Hybrid composites, where multiple fiber types exist in a single matrix, further increase the functionality of composites by allowing the designer to add selectivity stiffer, more costly fibers where the stresses are more critical and add less costly fibers where the stresses are less critical.
This research focuses on the structural behavior of hybrid composite tubes when subjected to internal pressure, axial tension, and dynamic forces induced by wave and current interaction. A closed form, shear deformable shell code is developed to capture the strain state of hybrid composite tubes under axisymmetric loads and finite element analysis is used to determine the behavior of a composite tube subjected to dynamic loads and pressure loads. Scaling methods by means of structural/material similitude are also studied. For composites, these scaling laws depend not just on geometry, but also on constituent properties and the location and orientation of the constituents in the system. Through similitude, the behavior of tubes which cannot be tested easily can be verified using tubes which are easier to test or have already been tested.