Random design variables and sensitivity factors applicable to ship structures considering combined bending moments

Abstract

Sensitivity analysis enables the designers to determine the most important random variable responsible for the failure of ship structures. Vertical bending is the most important to assess the strength of a ship, but horizontal bending moment also plays a pivotal role in the safety assessment of ship structures. The method for the reliability analysis taking account of the combined bending moment is presented. The interaction equation between the vertical and horizontal bending moments has been derived using Smith's method, and the limit state function for the reliability analysis has been modelled from the interaction equation. The wave loads are calculated using an International Association of Classification Societies (IACS) rule. The study shows the importance of the contribution of the design variables towards the uncertainty of the limit state function and the advantages for using the sensitivity factors for safety assessment of ship structures.

Keywords

ultimate strength interaction equation reliability analysis sensitivity factors

Get full access to this article

View all access options for this article.

References

Mansour

A. E.

Wirsching

P. H.

Sensitivity factors and their application to marine structures. Mar. Structs, 1995, 8, 229–255.

Das

P. K.

Fang

Survivability and reliability of damaged ships after collision and grounding. Ocean Engng, 2005, 32, 293–307.

Das

P. K.

Fang

Residual strength and survivability of ships after grounding and collision. J. Ship Res., June 2007, 51(2), 137–149.

4 Special Task Committee VI.1, Reliability based structural design and code development. In 16th ISSC, Southampton, 2006.

Liu

P. L.

Lin

H. Z.

Kiureghian

A. D.

CALREL user manual, Department of Civil Engineering, University of California at Berkeley, 1989.

Khan

I. A.

Das

P. K.

Parmentier

Ultimate strength and reliability analysis of a failed VLCC. In Proceedings of the 3rd International ASRANet Colloquium, Glasgow, 10–12 July 2006.

Mansour

A. E.

Lin

Y. H.

Paik

J. K.

Ultimate strength of ships under combined vertical and horizontal moments. In Proceedings of the 6th International Symposium PRADS1995, Seoul, South Korea, 1995 Vol.2, pp. 844–856.

Paik

J. K.

Thayamballi

A. K.

Che

J. S.

Ultimate strength of ship hulls under combined vertical bending and shear forces. SNAME Trans., 1996, 104, 31–59.

Gordo

J. M.

Guedes Soares

Collapse of ship hull under combined vertical and horizontal bending moments. In Proceedings of the 6th International Symposium PRADS1995, Seoul, South Korea, 1995 Vol.2, pp. 808–819.

10.

Gordo

J. M.

Guedes Soares

Interaction equation for the collapse of tankers and containerships under combined bending moments. J. Ship Res., 1997, 41(3), 230–240.

11.

Zhang

Sun

Analysis on the ultimate longitudinal strength of a bulk carrier by using a simplified method. Mar. Structs, 2001, 14, 311–330.

12.

Ozguc

Das

P. K.

Barltrop

A comparative study on the structural integrity of single and double side skin bulk carriers under collision damage. Marine Structures, 2005, 18, 511–547.

13.

Khan

I. A.

Das

P. K.

Residual strength and survivability of ships under combined vertical and horizontal bending. In Proceedings of Advancements in Marine Structures (MARSTRUCT) (Eds C. Guedes Soares and P. K. Das), 12–14 March 2007, pp. 197–206.

14.

Khan

I. A.

Das

P. K.

Structural safety assessment of damaged ships. In Proceedings of the 27th International Conference on Offshore mechanics and arctic engineering (OMAAE 2007), San Diego, California, 10–15 June 2007.

15.

Guedes Soares

Combination of primary load effects in ship structures. Probabilistic Engng Mechanics, 1992, 7, 103–11.

16.

Wang

Moan

Stochastic and deterministic combinations of still and wave bending moments in ships. Mar. Structs, 1996, 9, 787–810.

17.

Guedes Soares

Moan

Statistic analysis of still water load effects in ship structures. Trans. SNAAME 96, 1988.

18.

Mansour

A. E.

Thayamballi

Loads and load combinations. Ship Structure Committee Report SSC-373, April 1994.

19.

Mansour

A. E.

Lin

M. C.

Hovem

Thayamballi

Probability-based ship design procedures: a demonstration. Ship Structure Committee Report SSC-368, August 1993.