Πιθανοτική Αξιολόγηση του Κριτηρίου Δυναμικής Ευστάθειας Δεύτερης Γενιάς "Level 2 Deadship Condition failure mode"

Κυριακόπουλος, Παναγιώτης; Kyriakopoulos, Panagiotis

dc.contributor.author	Κυριακόπουλος, Παναγιώτης	el
dc.contributor.author	Kyriakopoulos, Panagiotis	en
dc.date.accessioned	2023-01-13T08:49:22Z
dc.date.available	2023-01-13T08:49:22Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/56667
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.24365
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-sa/3.0/gr/	*
dc.subject	Κριτήρια δεύτερης γενιάς	el
dc.subject	Πιθανοτική Αξιολόγηση	el
dc.subject	Δείκτης ευπάθειας κριτηρίου	el
dc.subject	Στατιστική Ανάλυση	el
dc.subject	Γραμμικοποιημένο και Μη Γραμμικό Μοντέλο	el
dc.subject	Second Generation Intact Stability Criteria	en
dc.subject	Level 2 Deadship Condition failure mode	en
dc.subject	Probabilistic evaluation	en
dc.subject	Vulnerability Index	en
dc.subject	Statistical Comparison between Linearized Model and Nonlinear Model	el
dc.title	Πιθανοτική Αξιολόγηση του Κριτηρίου Δυναμικής Ευστάθειας Δεύτερης Γενιάς "Level 2 Deadship Condition failure mode"	el
dc.title	Probabilistic Evaluation of the Second Generation Intact Stability Criterion "Level 2 Deadship Condition failure mode"	en
heal.type	bachelorThesis
heal.classification	Δυναμική Ευστάθεια Πλοίου	el
heal.classification	Ship's Dynamical Stability	en
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2022-10-19
heal.abstract	In the present thesis, the second generation intact stability criterion known as “Level 2 Deadship Condition failure mode criterion” was studied and evaluated probabilistically. The scientific background of this specific criterion has been considered and, in particular, the οriginal nonlinear differential equation of roll motion and the respective linearized, on which the criterion is based. The assessment procedure stipulated in the criterion has been applied in order to estimate the, representative of stability, probabilistic vulnerability index C. Four loading conditions of a specific modern containership were studied, the corresponding values of the index C were calculated and thewy were compared against the permitted limit value R=0.06. Furthermore, a statistical analysis of data, which were obtained from the two juxtaposed mathematical models, nonlinear and linearized, was carried out. Specifically, massive simulations of ship’s roll behaviour due to the simultaneous action of wind and waves were conducted. These excitations were expressed via the Random Phase Model- RPM. Then, statistical data, corresponding to the ship’s steady-state roll, were extracted. From these data, histograms were produced and Probability Density Functions (PDFs) were fitted to them. In the case of the linearized model, this was done for verifying the calculation procedure considering that, for excitation following the Normal (Gaussian) distribution, the response will follow the same distribution. In the context of the examined criterion, it should be pointed that the waves, which are expressed by the sea surface’s elevation, and the wind, which is expressed by the gust wind’s speed, are considered to follow the Normal distribution. In the case of nonlinear model, the distinction between response’s distribution and Normal distribution was evaluated. The histograms were produced neglecting time-series/simulations in which the system escaped to infinity. This can happen only in reference to the non-linear model of roll motion. Thus, via statistical analysis, important statistical values such as mean value, variance-standard deviation and others were calculated. Afterwards, accounting also for the escape cases of the nonlinear system, semi-logarithmic diagrams of statistical probability of exceedance of rolling angles were produced. In that point, it should be highlighted that three differents cases of excitation were subjected for each loading condition, represented by the same significant wave height Hs and by a different mean zero up-crossing period Tz. More specifically, excitation scenarios where the peak frequency of representative Bretchneider Wave Spectrum coincided with the natural frequency of the system, for each loading condition; and also, other excitation scenarios in which the peak period of the spectrum was relatively far apart from the natural period (or it simply didn’t coincide) were analyzed. The effect of the last one mentioned excitation scenarios presents a strong interest mainly in the case of non-linear modelling of the system. However, most of the excitation cases analyzed, constitute realistic scenarios and they were selected from the well-known Wave Scatter Table (IACS, 2011)[4] in order that the possibility of occurring in 100000 observations not to be negligible. Following the comparison between the statistical results of the linearized and the counterparts of the nonlinear model, aggregate assessment was conducted, in which, among others, statistical results were correlated with the vulnerability indeces of relevant second generation criterion. Finally, summaries and brief comments regarding the significant results and findings of this investigatory thesis were quoted.	en
heal.advisorName	Σπύρου, Κωνσταντίνος	el
heal.advisorName	Spyrou, Kostantinos	en
heal.committeeMemberName	Σπύρου, Κωνσταντίνος	el
heal.committeeMemberName	Θεμελής, Νικόλαος	el
heal.committeeMemberName	Παπαδόπουλος, Χρήστος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Μελέτης Πλοίου και Θαλάσσιων Μεταφορών	el
heal.academicPublisherID	ntua
heal.fullTextAvailability	false