Ανάπτυξη μοντέλου υπολογισμού των παραμορφώσεων γάστρας πλοίου, με εφαρμογή στη βέλτιστη ευθυγράμμιση του αξονικού συστήματος

Δαρδαμάνης, Αναστάσιος; Dardamanis, Anastasios

dc.contributor.author	Δαρδαμάνης, Αναστάσιος	el
dc.contributor.author	Dardamanis, Anastasios	en
dc.date.accessioned	2022-11-29T08:57:25Z
dc.date.available	2022-11-29T08:57:25Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/56283
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.23981
dc.rights	Default License
dc.subject	Δομική Ανάλυση	el
dc.subject	Μέθοδος Πεπερασμένων Στοιχείων	el
dc.subject	Ευθυγράμμιση Άξονα	el
dc.subject	Βελτιστοποίηση Ευθυγράμμισης Άξονα	el
dc.subject	Θεωρία Δοκού Timoshenko	el
dc.subject	Structural Analysis	en
dc.subject	Shaft Alignment	en
dc.subject	Timoshenko Beam Theory	en
dc.subject	Finite Element Method	en
dc.subject	Shaft Alignment Optimization	en
dc.title	Ανάπτυξη μοντέλου υπολογισμού των παραμορφώσεων γάστρας πλοίου, με εφαρμογή στη βέλτιστη ευθυγράμμιση του αξονικού συστήματος	el
heal.type	bachelorThesis
heal.secondaryTitle	Development of model for the calculation of ship hull deflection, with application to the optimal alignment of propulsion shafting system	en
heal.classification	Structural Engineering	en
heal.language	el
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2022-07-20
heal.abstract	Proper shaft alignment is vital for the safe operation and efficient performance of a vessel. Until recently, hull deflections had been rarely considered in the calculations of shaft alignment, mainly due to the time-consuming task of creating a 3d finite element representation of the vessel, and solving for many different loading condition scenaria. However, for some loading conditions, the effect of hull deformation on bearings vertical displacement and corresponding loads is quite significant. Having the ability to account for hull deflections in an early design stage will lead to increased calculations quality, will aid in preventing bearing operation at very low / very high loads and increased possibility of failure, while it will minimize dependence on the experience of shipyard personnel, which could be of particular concern when implementing alignment on new hull designs. The addition of hull deflections in the alignment design allows bearing reactions to be accurately assessed and confirmed for every vessel loading condition. Recently, Classification Society ABS released rule notations concerning the shaft alignment procedure, and noted that the 1D beam theory finite element model can provide acceptable hull deflection estimates, in comparison to deflections obtained from complex 3D finite element analyses. In the present work, the hull deflections of a typical 10K containership are being calculated with the use of 1d beam theories. In particular, the Euler- Bernoulli and Timoshenko beam theories have been used to determine the hull deflections of the vessel. A Graphical User Interface application was developed in the course of the present thesis to calculate the sectional properties, such as neutral axis, second moment of area and shear area, for several longitudinal transverse sections of the containership and to automate the procedure of shaft alignment calculations. Several parts of the vessel must be taken into account in the calculations to properly assess the vertical bearings’ offsets. After the transverse bending, shear stiffness and load distribution for several frames has been used as input, the finite element method is utilized to calculate relative hull deflections for a series of representative loading conditions of the vessel. This method not only provides a robust early approximation of the hull deflection using the broadly available information, but also requires minimum pre-processing by the user. The aforementioned vertical offsets due to hull deflections are used in combination with the vertical offsets from hydrodynamic lubrication characteristics (oil film thickness) and elastic bearing foundation to calculate the bearings’ reaction forces. The proper investigation and assessment of the bearings’ offsets leads to better efficiency of the propulsion system, less wearing down of the journal bearings and increased bearing reliability. Based on the above, conclusions are drawn regarding the errors that can be produced by both the 3d and 1d modeling of the vessel and important parameters that should be considered beforehand to create a more accurate model. Additionally, a comparative analysis of the key parameters affecting the shaft alignment procedure is conducted and a review of those key factors, including but not limited to the ship voyage and the sea swell, but also the many parameters that should be considered beforehand. Finally, suggestions for future work are discussed, that would extend the work done in this thesis and broaden our knowledge about the parameters affecting the hull deflection.	en
heal.advisorName	Παπαδόπουλος, Χρήστος
heal.committeeMemberName	Ανυφαντής, Κωνστανίνος	el
heal.committeeMemberName	Καΐκτσής, Λάμπρος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής Μηχανολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	126 σ.	el
heal.fullTextAvailability	false