Sage Journals: Discover world-class research

Abstract

This paper presents the findings of a study on the air gap below deck of a typical six-column, double-pontoon semi-submersible in deep water. The writers present a method to predict the extreme air-gap by establishing the distribution of extreme air-gap response. In the case of linear incident wave, the proposed air-gap distribution suggested a better fits compared with that given by Rayleigh distribution. Moreover, the proposed approach is found to be an effective way to predict air-gap extremes within a specified duration. As a comparison, the fractile-based method cum Gumbel distribution is also applied to the same floating structure. Comparisons of the numerical results from these 2 different approaches show strong agreement in extreme air-gap response below deck.

Keywords

under deck air gap floating structures extreme air gap response numerical analysis

References

Cartwright

D.E.

Longuet-Higgins

M. S.

(1956). The statistical distribution of the maxima of a random function. Proceedings of the Royal Society of London, A237: 212–232.

Chakrabarti

S. K.

(1987). Hydrodynamics of Offshore Structures, Computational Mechanics Publications, Southampton.

Davenport

A. G.

(1964). Note on the distribution of the largest value of a random function with application to gust loading. Proceedings of the Institution of Civil Engineers, 28:187–196.

Hasselmann

Barnett

T P

Bouws

(1973). Measurements of wind wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP). Erganzungsheft Zeit Deut Hydr Zeit, 12: 1–95.

Kurniawan

Huang

Liu

Wang

Hao

Tan

S.K.

Edwin

, (2009). A numerical analysis of the response and air gap Demand for Semi-submersibles, Proceedings of the 29^th International Conference on Offshore Mechanics and Arctic Engineering (OMAE2009).

Lee

C.-H.

(1995). WAMIT Theory Manual. MIT. Report 95–2, Dept. of Ocean Engineering, MIT.

Madsen

H. O.

Krenk

Lind

N. C.

(1986). Methods of Structural Safety. New Jersey: Prentice-Hall, Inc.

Manuel

and Winterstein

(2000). Reliability-based predictions of a design air gap for floating offshore structures. 8th ASCE Specialty Conference on Probabilistic Mechanics and Structural Reliability.

Nielsen

F. G.

(2003). Comparative study on airgap under floating platforms and run-up along platform columns, Marine Structures, 16: 97–134.

10.

Pearson

Lee

(1903). On the law of inheritance in man. Biometrika, 2: 357–462.

11.

Qiu

(1999). Engineering Hydrology (in Chinese). People's Communication Press, Beijing.

12.

Sweetman

(2004). Practical Airgap Prediction for Offshore Structures. Journal of Offshore Mechanics and Arctic Engineering, 126: 147–155.

13.

Sweetman

(2001). Airgap analysis of floating structures subject to random seas: Prediction of extremes using diffraction analysis versus model test results. PhD Thesis, Stanford University.

14.

WAMIT (2006). WAMIT User Manual. WAMIT, Inc. Available from the website http://www.wamit.com.

15.

Winterstein

S. R.

Ness

O.B.

(1989). Hermite moment analysis of nonlinear random vibration. Computational mechanics of probabilistic and reliability analysis. Lausanne, Swizerland: Elme Press: 452–478.

Extreme Air-Gap Response below Deck of Floating Structures

Abstract

Keywords

References