Global wave loads on a damaged ship

Abstract

A computational tool was applied based on a two-dimensional linear method to predict the hydrodynamic loads for damaged ships. Experimental tests on a ship model have also been carried out to predict the hydrodynamic loads in various design conditions. The results of the theoretical method and experimental tests are compared to validate the theoretical method. The extreme wave-induced loads have been calculated by short-term prediction. For the loads in intact condition, the prediction with a duration of 20 years at sea state 5 is used, while for loads in damaged conditions, the prediction with 96 hours of exposure time at sea state 3 is used. The maximum values of the most probable extreme amplitudes of dynamic wave-induced loads in damaged conditions are much less than those in intact condition because of the reduced time. An opening could change the distribution of not only still-water bending moment but also wave-induced bending moment. It is observed that although some cross-sections are not structurally damaged, the total loads acting on these cross-sections after damage may be dramatically increased compared with the original design load in intact condition.

Keywords:

• damaged ship
• flooding
• model test
• static load
• wave-induced load
• short-term prediction

Acknowledgements

The authors wish to acknowledge Dr. Paul Hess for his enthusiastic and enormous effort in securing the funding and then actively collaborating with us in this project. Our gratitude goes to ONR for sponsoring this research. The contributions of Prof. Mehmet Atlar and Prof. Martin Downie of Newcastle University are also acknowledged. It is noted that all research works in this paper were carried out during Dr. Yongwon Lee's Ph.D. course at Newcastle University.

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