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Design of a ship model for hydro-elastic experiments in waves

  • 발행 : 2014.12.31

초록

Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

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참고문헌

  1. Ciappi, E., Dessi, D. and Mariani, R., 2003. Slamming and whipping response analysis of a fast monohull via a segmented model test. Hydroelasticity in Marine Engineering, Hydroelasticity '03, Oxford, UK, 15-17 September 2006, pp.143-153.
  2. Dessi, D., Mariani, R., La Gala, F. and Benedetti, L., 2003. Experimental analysis of the wave induced response of a fast monohull via segmented-hull model. FAST 2003 conference, Ischia, Italy, 7-10 October 2003, pp.75-82.
  3. Dessi, D. and Mariani, R., 2006. Slamming load analysis of a fast vessel in regular waves: a combined numerical/ experimental approach. 26th Symp on Naval Hydrodynamics, Rome, 17-22 September 2006.
  4. Drummen, I., 2008. Experimental and numerical investigation of nonlinear wave induced load effects in containerships considering hydroelasticity. Ph.D. thesis. Department of Marine Technology, Norwegian University of Science and Technology, Trondheim, Norway.
  5. Hay, B., Bourne, J., Engle, A. and Rubel, R., 1994. Characteristics of hydrodynamic loads data for a naval combatant. Hydroelasticity in Marine Technology 1994, Trondheim, 22-28 May 1994, pp.169-188.
  6. Hong, S.Y., Kim, B.W. and Nam, B.W., 2011. Experimental study on torsion springing and whipping of a large container ship. 21st Int. Offshore and Polar Engineering Conference (ISOPE), Hawaii, USA, 19-24 Jun 2011, pp.486-494.
  7. Hong S.Y., Kim, K.H., Kim, B.W. and Kim, Y.S., 2014, Experimental Study on the Bow-Flare Slamming of a 10000 TEU Containership, 24th Int Ocean and Polar Eng Conf (ISOPE), Busan, Korea, 15-20 Jun 2014, pp.816-823.
  8. Iijima, K., Hermundstad, O.A., Zhub, S. and Moan, T., 2009. Symmetric and antisymmetric vibrations of a hydroelastically scaled model. Hydroelasticity in Marine Technology 2009, Southampton, UK, 8-10 September 2009, pp.173-182.
  9. Kapsenberg, G.K. and Brizzolara, S., 1999. Hydroelastic effects of bow flare slamming on a fast monohull. FAST-99, Seattle, 31 August - 2 September 1999.
  10. Lavroff, J., Davis, M.R, Holloway, D.S. and Thomas, G., 2007. The whipping vibratory response of a hydroelastic segmented catamaran model. 9th Int. Conf. on Fast Sea Transportation, FAST2007, Shanghai, China, 23-27 September 2007, pp. 600-607.
  11. Lewis, E.V., 1954. Ship model tests to determine bending moments in waves. Transpotation of the Society of Naval Architects and Marine Engineers (SNAME), 62, pp.426-490.
  12. Malenica, S., Molin, B., Remy, F. and Senjanovic, I., 2003. Hydroelastic response of a barge to impulsive and non-impulsive wave loads. Hydro-elasticity in Marine Technology 2003, Oxford, UK, 15-17 September 2003, pp. 107-115.
  13. McTaggart, K., Datta, I., Stirling, A., Gibson, S. and Glen, I., 1997. Motions and loads of a hydroelastic frigate model in severe seas. SNAME Annual meeting, Ottawa, 15-18 October 1997, pp.1-24.
  14. Miyake, R., Matsumoto, T., Zhu, T., Usami, A. and Dobashi, H., 2009. Experimental studies on the hydroelastic response using a flexible mega-container ship model. Proceedings of 5th International Conference on Hydroelasticity in Marine Technology, Southampton, UK, 8-10 September 2009, pp.161-171.
  15. Miyake, R., Matsumoto, T., Yamamoto, N. and Toyoda, K., 2010. On the estimation of whipping/springing response acting on a Ultra Large Container Ship. ITTC workshop on Seakeeping, Seoul, Korea, 19-21 October 2010, pp.175-185.
  16. Sawada, H., Watanabe, I., Yamamoto, T., Tanizawa, K., Ishida, S., Ueno, M. and Miyamoto, T., 1987. On an elastic model to simulate elastic hull responses of ships, report. Japan: Ship Research Institute, Ministry of Transport.
  17. Storhaug, G. and Moan, T., 2006. Springing/whipping response of a large ocean going vessel - Investigated by an experimental method. 4th Symp on Hydro-elasticity in Marine Technology, Wuxi, China, 10-14 September 2006, pp.89-102.
  18. Watanabe, I., Ueno, M. and Sawada, H., 1989. Effects of bow flare shape to the wave loads of a containership. Jorunal of the Society of Naval Architects of Japan, 166, pp.259-266.
  19. Wu, M.K, Hermundstad, O.A. and Zhu, S., 2010. Comparative study of springing and whipping effects in Ultra Large container ships. ITTC workshop on Seakeeping, Seoul, Korea, 19-21 October 2010, pp.270-282.