Modelling a foil load spectrum using recorded data on a racing foiling yacht

The intent of this Master Thesis is to investigate foil loadings on racing foiling yacht based on recorded data. This work was done by means of recorded microstrains along the foil and other recorded data such as boat speed and fly height. Composite foils are developed by the company GSea Design usi...

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Bibliographic Details
Main Author: Gros-Borot, Maeva
Format: Others
Language:English
Published: KTH, Marina system 2018
Subjects:
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226532
Description
Summary:The intent of this Master Thesis is to investigate foil loadings on racing foiling yacht based on recorded data. This work was done by means of recorded microstrains along the foil and other recorded data such as boat speed and fly height. Composite foils are developed by the company GSea Design using an in-house software called Sofia which uses Fluid Structure Interaction (FSI) to design deformable appendages. In this Master Thesis, a tool that enables to get a numerical model of the foil adjusted to the recorded strains at a given time was designed. For that, recorded strains along the foil were first evaluated and post-processed to calculate the corresponding bending moments along the foil. Then an optimization loop based on the Sofia software was implemented. This loop automatically adjusts the numerical model of the foil to the recorded bending moments and computes the global Up and Side forces (vertical and anti- leeway forces, respectively) applied on the foil that contribute to the boat’s equilibrium. This approach was set up and tested during this Master Thesis. It enabled to show that building a representative load case in terms of global Up and Side forces with the corresponding numerical model using recorded data at a given time was possible. This work also highlighted some remaining constraints such as long calculation times to get an adjusted model automatically on recorded data. It implies that future work on data processing or optimisation improvements will constitute the next steps developed by GSea Design to be able to set up a foil design in terms of lifetime. === Avsikten med detta examensarbete är att undersöka bärplansbelastningar på en foilande racingsegelbåt baserat data uppmätta under segling, såsom töjningar i bärplanen, båthastighet, och flyghöjd. Kompositbärplan utvecklas av företaget GSea Design med hjälp av en egen mjukvara som heter Sofia, som bygger på modellering av fluid-struktur interaktion (FSI). I detta examensarbete har ett verktyg utvecklats som gör det möjligt att justera en numerisk modell av ett bärplan till uppmätta töjningar vid en given tidpunkt. Med utgångspunkt från uppmätta töjningar i bärplanet beräknas först motsvarande böjningsmoment längs bärplanet. Därefter implementerades en optimeringsprocedur baserat på Sofia som automatiskt anpassar bärplansmodellen till de uppmätta böjningsmomenten och beräknar de globala upp- och sidokrafterna (tillhörande vertikala och avdrift krafterna) på bärplanet som bidrar till båtens jämvikt. Utvärdering visar att den utvecklade metodiken fungerar bra för att formulera representativa lastkonditioner. Återstående begränsningar diskuteras, som till exempel att långa beräkningstider krävs, och rekommendationer ges för fortsatt utveckling av databehandling och optimeringsförbättringar för att möjliggöra bärplansdesign baserat på livstidsanalys.