“Damping Factors in the Higher Modes of Ship Vibrations”

Kumai, Toyoji

doi:10.2534/jjasnaoe1952.1957.102_143

Cited by 7 publications

(5 citation statements)

References 1 publication

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“…Based on modeling experience, roll damping was defined at a fraction corresponding to 7% of critical damping and was applied by way of 50% of the wetted hull nodes and 50% of the bilge keel nodes. Structural damping was defined according to Kumai empirical factors [39]. A summary of the dry and wet resonance characteristics is given in Table 4.…”

Section: Wet Analysismentioning

confidence: 99%

Springing Analysis of a Passenger Ship in Waves

Tilander

Patey²,

Hirdaris

2020

JMSE

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Traditionally, the evaluation of global loads experienced by passenger ships has been based on closed-form Classification Society Rule formulae or quasi direct analysis procedures. These approaches do not account for the combined influence of hull flexibility, slenderness, and environmental actions on global dynamic response. This paper presents a procedure for the prediction of the global wave-induced loads of a medium-size passenger ship using a linear potential flow flexible fluids interaction model. The study compares results from direct long-term hydro-structural computations against Classification Society Rules. It is demonstrated that for the specific vessel under consideration: (a) the elastic contributions of the responses on loads are negligible as springing effects occur outside of the wave energy spectrum, (b) deviations of the order of 28% arise by way of amidships when comparing direct hydrodynamic analysis predictions encompassing IACS UR S11A hog/sag nonlinear correction factors and the longitudinal strength standard, and (c) the interpretation of the wave scatter diagram influences predictions by approximately 20%. Based on these indications, it is recommended that further parametric studies over a range of passenger ship designs could help draw unified conclusions on the total influence of global and local hydrodynamic actions on passenger ship loads and dynamic response.

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Section: Wet Analysismentioning

confidence: 99%

Springing Analysis of a Passenger Ship in Waves

Tilander

Patey²,

Hirdaris

2020

JMSE

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“…The remaining structural system m atrix b has its first rows and columns null assuming m bodily motions, but the remaining square m atrix of order 1 is something th a t we know very little about. Indeed, but for the pioneering work of Kumai (1958), we should be almost without reliable evidence on this aspect. It is interesting to reflect th a t the change from riveted construction to welding may have made an enormous difference to this particular m atrix and conceivably a large difference to ships' safety a t sea as a consequence.…”

Section: The Flexible Shipmentioning

confidence: 99%

Some comments on present-day ship dynamics

Bishop

Price

Victory³

1991

Phil. Trans. R. Soc. Lond. A

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“…The deck area by way of hatch end beams was considered to be longitudinally ineffective. Structural damping factors, based on Kumai's [68] formulation for a long slender monohull in a ballast loading condition, were used. Four distortion modes were included in the analysis and predictions were obtained both in regular and long-crested irregular waves.…”

Section: Service Factor Assessment For a Great Lakes Bulk Carriermentioning

confidence: 99%

Hydroelasticity of ships: Recent advances and future trends

Hirdaris

Temarel

2009

Proceedings of the Institution of Mechanical Engineers, Part M:

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Investigations into hydroelasticity of ships commenced in the 1970s. Since then the theory has been employed to predict the responses of a wide range of marine structures, such as mono- and multihulled ships, offshore structures, and VLFS. In recent years, with increasing market demands for new buildings of slender ocean going carriers and the continuously updated high-speed and unconventional multihulled designs, the maritime industry began to notice the advantage of assessing the usefulness and applicability of hydroelasticity in ship design. At first instance, the aim of this paper is to illustrate some of the applications of hydroelasticity theory to ships, with particular reference to recent and ongoing developments focusing on ship design applications and the effects of non-linearities and viscous flows. The paper also discusses the longer term potential use of weakly and fully non-linear fluid—structure interaction, as well as Navier—Stokes based fluid dynamic methods, for the improved modelling of ship dynamic response problems.

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“Damping Factors in the Higher Modes of Ship Vibrations”

Cited by 7 publications

References 1 publication

Springing Analysis of a Passenger Ship in Waves

Springing Analysis of a Passenger Ship in Waves

Some comments on present-day ship dynamics

Hydroelasticity of ships: Recent advances and future trends

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