Dimensioning of marine propulsion shafts
Typ
Examensarbete för masterexamen
Program
Naval architecture and ocean engineering (MPNAV), MSc
Publicerad
2021
Författare
Gunnarsson, Gudni
Sigurdsson, Sindri
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Dimensioning of marine propulsion shafts for new builds is done early in the design
phase of a vessel. Thus, often the designer only has the main particulars of the vessel
including the general size and power requirements, as well as the intended purpose
of the vessel. With the limited information, a shaft line needs to be dimensioned
which is fit for purpose, fulfils class requirements as well as showing good vibrational
behavior. Until now this has been done safely and successfully using old principles
and fundamentally relying on a single formula that is recognized by all the major
classification societies for giving a safe design. This method has been shown to
give very reliable designs but is however believed to result in overly dimensioned
components. By utilizing expertise, access to good data, and a systematic approach
in behavior analysis, it is believed to be possible to step away from current methods
and provide slimmer and more power-dense shaft lines.
This thesis describes the underlying theory of rotating machinery often summarized
as rotor dynamics. A comprehensive study of classification rules and requirements
governing the design of marine propulsion shafts. Case studies of typical shaft lines
for different types of vessels, for those a software tool from DNV-GL is used to
simulate the shaft behavior. The simulation software Nauticus Machinery available
from DNV-GL is a specialized marine shaft line analysing software, containing few
different tools. The tools used during this thesis work are Nauticus Shaft Alignment,
Nauticus Torsional Vibration, and approved formulas and equations from classification
societies. Using this combination of software and formulas the writers evaluate
an improved method to define the minimum shaft diameter.
Beskrivning
Ämne/nyckelord
propulsion shaft , whirling , torsional vibration , shaft alignment , shaft dimensioning , classification societies