Assessment of the OTEC cold water pipe design under bending loading: A benchmarking and parametric study using finite element approach

Ocean thermal energy conversion (OTEC) is a f loating platform that generates electricity from seawater heat. The cold water pipe (CWP) used in OTEC has a length of 1,000 m and a diameter of 10m, making it susceptible to bending loads from ocean currents. To find suitable geo metry and material for the CWP, the finite element method was used to model the real-world geometry. In the D/t var iation, lower ratios (increased thickness) result in higher critical moments, maximum stress, strain, and displace ment. D/t 50 was chosen for the CWP. In the L/D variation, the critical moment’s impact on L/D ratio was minimal, while reducing L/D (shorter pipe) increased strain, and larger L/D geometries had higher displacements. L/D 10 was selected as it balanced critical moments and reduced the number of stiffeners needed. For diameter size varia tion, larger diameters increased critical moment and strain, but smaller diameters (larger L/D ratios) also showed high strain due to necking at two points. A diameter of 12m was chosen for its exceptionally high critical moment. Steel was selected as the suitable material due to its higher critical moment and maximum stress, despite its higher weight and lower maximum strain than composites. Capital shape imperfections had a minimal effect on the CWP’s structure as they were localized