Print Email Facebook Twitter The design, production and verification of a fully elastic model of a catamaran for hydroelastic experiments Title The design, production and verification of a fully elastic model of a catamaran for hydroelastic experiments Author Keser, Anabel (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Ship and Offshore Structures; TU Delft Ship Hydromechanics) Contributor Grammatikopoulos, A. (mentor) Seyffert, Harleigh C. (graduation committee) den Besten, J.H. (graduation committee) Verdult, Michiel (mentor) Degree granting institution Delft University of Technology Programme Marine Technology | Ship and Offshore Structures Date 2023-10-11 Abstract Catamarans are popular in the offshore sector as they combine good transverse stability and ample deck space with low wave resistance. However, their slender hull shape results in low restoring qualities in heave and pitch motions. The large motions in rough weather can often result in water impacting the underside of the deck connecting the two hulls, a phenomenon called cross-deck slamming. The impulse excitation from cross-deck slamming can then produce a transient hydroelastic response of the structure called whipping. Whipping excites mode shapes that would not normally be present in the response, as their natural frequencies are significantly higher than the wave encounter frequency. This results in detrimental contributions to fatigue life through high-amplitude cyclical bending moments. Both the calculation of slamming loads and the prediction of resulting structural responses have been a challenge for several decades. The highly nonlinear and three-dimensional character of the phenomenon, combined with the strongly coupled fluid-structure interaction means that it is unpredictable, and even the definition of slamming events has been a matter of disagreement among researchers.\\Experiments are still a vital part of these investigations, for validating ever-improving numerical techniques. An essential issue with experiments is the extent to which mode shapes and natural frequencies can be emulated in model scale. Traditional hydroelastic models are segmented and use either a flexible backbone or flexible joints to introduce stiffness. This often results in an excellent description of the 2-node bending mode, but an increasing error for higher modes leads to stress inaccuracies. In this investigation, a fully elastic model of a catamaran is designed and produced for hydroelastic experiments. The advantages and limitations of the concept are identified, and the verification against structural models is presented. Subject Additive ManufacturingElastic modelHydroelasticitySlamming To reference this document use: http://resolver.tudelft.nl/uuid:b5ca1efe-8c2f-4af4-82f8-beee4f3273ce Part of collection Student theses Document type master thesis Rights © 2023 Anabel Keser Files PDF Thesis_Anabel_Keser.pdf 31.28 MB Close viewer /islandora/object/uuid:b5ca1efe-8c2f-4af4-82f8-beee4f3273ce/datastream/OBJ/view