University of Twente Student Theses
Towards a parametric optimization tool for hydrofoil design
Jansen, S.L. (2022) Towards a parametric optimization tool for hydrofoil design.
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| Abstract: | Hydrofoils show potential in improving comfort and efficiency of fast passenger ships. With advances in materials science, fiber reinforced polymer (FRP) structures are considered as a potential new structural material for this specific application, capable of dealing with high loads and corrosive maritime environments. The aim of this project was to provide a clear analytical procedure to come to a structurally safe hydrofoil design, both for traditional isotropic materials as well as for FRP laminates. The knowledge had to be applied in a fast optimization tool to create preliminary structural designs at low cost. The static loads on the structure are identified. The stresses resulting from these loads are evaluated for both isotropic materials as well as for FRPs using Classical Laminate Theory (CLT). Using the analytical expressions, a MATLAB based optimization tool is created, iteratively finding a structure with the lowest possible volume. Optimization is done by minimizing the foil volume, to limit the adverse effects of added drag, using failure criteria as constraints. The results from the optimization tool are verified using Finite Element (FE) simulation models. The tool is applied to the design of a 45 ton monohull and 175 ton catamaran ship in a case study. In validation, the tool performed well for both isotropic and laminated structures. Results were determined to be conservative, with deflections in FE simulations mostly lower than predicted. On average, FE deflections for (quasi-)isotropic designs exceeded analytical results by 10% at most. Higher error was seen in structures with increased directional reinforcement. The error was minimized after inclusion of shear webbing, reducing warping. Reinforcement in both principal directions as well as for shear was critical for accurate results. Stress results proved difficult to compare, as the inclusion of spars to increase the deflection accuracy lead to stress concentrations, decreasing the stress accuracy. Results from the optimization tool proved useful for creating a preliminary design quickly. For the monohull vessel, maximum foil skin thicknesses of 16.2mm (steel) and 25.2mm (Carbon FRP) were found for the front foil. 3D Structure displacement was found to be 9.9% and 8.76% more than the 2D estimation for steel and FRP, respectively. Internal structures were vital to maintain the constant geometrical shape along the entire foil. This was seen in the design for the catamaran rear foil, where local deformation was found to be 91.4% above the expected average value while sections without local deformation were 5.7% above the expected displacement. |
| Item Type: | Essay (Master) |
| Clients: | Damen Shipyards |
| Faculty: | ET: Engineering Technology |
| Subject: | 52 mechanical engineering |
| Programme: | Mechanical Engineering MSc (60439) |
| Link to this item: | https://purl.utwente.nl/essays/90692 |
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