| Περίληψη: | Mast and rigs of a sailboat are the structural components responsible for transferring sail loads to the ship’s hull, thus, converting wind energy into kinetic energy. Masts are long and slender structures which should have sufficient stiffness and strength properties to effectively carry sail loads without buckling or exhibiting material failure. Composite materials are chosen when designing a mast tube not only due to their high strength- and stiffness-to-weight ratios but also due to the customizable properties of the final product their anisotropic nature offers. In this thesis, a composite mast of the 14m long sailboat ‘Oneiro’ is structurally analyzed and redesigned accordingly. An Analytical Method, based on Nordic Boat Standard, and a Finite Element (FE) Method, based on a Germanischer Lloyd Guideline, are selected and compared for the dimensioning and structural validation of mast, spreaders and shrouds. Buckling and material failure of the mast tube is assessed through these analyses. Moreover, an additional FEA, considering pretension of shrouds is performed, in purpose of evaluating the effect of this ‘real-life’ procedure on the elastic behavior and structural integrity of the mast and its components. However, in these FEA mast tube is generated from beam elements, thus, the various openings for different attachments along its length are not considered. For this reason, a FE Model of the mast with shell elements, including each real hole and opening, is structurally analyzed. Material failure is exhibited on critical mast segments close to openings, thus, patches with extra fabric plies are placed accordingly to offer sufficient support and eradicate failure.
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