Ultimate strength of hull girder for passenger ships

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Naar, Hendrik
dc.date.accessioned 2012-02-17T07:32:08Z
dc.date.available 2012-02-17T07:32:08Z
dc.date.issued 2006-03-10
dc.identifier.isbn 951-22-8029-9
dc.identifier.issn 1795-4584
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2669
dc.description.abstract The ultimate strength of the hull girder for large passenger ships with numerous decks and openings was investigated. The collapse of the hull girder, composed of the hull itself and the superstructure, as compared to a single deck ship with a continuous structure, involves several important structural phenomena that complicate understanding of this process. In this study, a theory of a non-linear coupled beam method was created. This method enables one to estimate the non-linear response of a passenger ship with a large multi-deck superstructure subjected to longitudinal bending. The method is based on the assumption that the ship structure can be modelled as a set of coupled beams. Each deck in the superstructure and also in the main hull can be considered as a thin-walled beam with non-linear structural behaviour. These beams are coupled to adjacent beams with non-linear springs called vertical and shear members, modelling the stiffness properties of the longitudinal bulkheads, side shells and pillars. Special emphasis was placed on the modelling of the shear members. A semi-analytic formula of the load-displacement curve was developed by help of the non-linear finite element analysis. Also, the load-end shortening curves under axial load taken from the literature were validated with the finite element method. The reverse loading options are included into the behaviour of the structural members. The created approach allows the calculation of the normal stresses and vertical deflections in the arbitrary location of the whole hull girder. Average longitudinal displacements and deflections of deck structures and shear stresses in the side structures can be estimated as well. The method is a further development of the linear coupled beam method. The ultimate strength of the hull girder was studied also with the non-linear finite element method. This required an investigation of the element mesh configuration in order to find an optimum mesh type and size. The prismatic hull girder of a post-Panamax passenger ship was chosen as a case study. The ultimate strength was estimated both in hogging and sagging loading with the coupled beam method and with the finite element method. The results of these two different methods, presented in the form of the bending moment versus the deflection of the hull girder, show good correlation up to the area where the moment starts to decrease. In both loading cases, the failure starts by the shear collapse in the longitudinal bulkhead. The ultimate stage of the strength was reached in the sagging loading when the failure progressed to the lower decks and correspondingly, in the hogging loading when the bottom structures failed in compression. The results on the structural failure modes show clearly that the shear strength of the longitudinal bulkheads and side structures is a very important issue on the ultimate strength problem of a passenger ship. en
dc.format.extent 102
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries TKK dissertations en
dc.relation.ispartofseries 22 en
dc.subject.other Mechanical engineering en
dc.subject.other Hydrology en
dc.title Ultimate strength of hull girder for passenger ships en
dc.type G4 Monografiaväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Mechanical Engineering en
dc.contributor.department Konetekniikan osasto fi
dc.subject.keyword coupled beam en
dc.subject.keyword finite element en
dc.subject.keyword superstructure en
dc.subject.keyword passenger ship en
dc.subject.keyword ultimate strength en
dc.identifier.urn urn:nbn:fi:tkk-006566
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (monografia) fi
dc.type.ontasot Doctoral dissertation (monograph) en
dc.contributor.lab Ship Laboratory en
dc.contributor.lab Laivalaboratorio fi

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