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Analysis Method of Ice Load and Ship Structural Response due to Collision of Ice Bergy Bit and Level Ice

유빙 및 평탄빙의 충돌에 의한 빙하중과 선체구조응답 해석기법

Nho, In Sik;Lee, Jae-Man;Oh, Young-Taek;Kim, Sung-Chan
노인식;이재만;오영택;김성찬

  • Received : 2015.10.02
  • Accepted : 2016.02.23
  • Published : 2016.04.20

Abstract

The most important factor in the structural design of ships and offshore structures operating in arctic region is ice load, which results from ice-structure interaction during the ice collision process. The mechanical properties of ice related to strength and failure, however, show very complicated aspect varying with temperature, volume fraction of brine, grain size, strain rate and etc. So it is nearly impossible to establish a perfect material model of ice satisfying all the mechanical characteristics completely. Therefore, in general, ice collision analysis was carried out by relatively simple material models considering only specific aspects of mechanical characteristics of ice and it would be the most significant cause of inevitable errors in the analysis. Especially, it is well-known that the most distinctive mechanical property of ice is high dependency on strain rate. Ice shows brittle attribute in higher strain rate while it becomes ductile in lower strain rate range. In this study, the simulation method of ice collision to ship hull using the nonlinear dynamic FE analysis was dealt with. To consider the strain rate effects of ice during ice-structural interaction, strain rate dependent constitutive model in which yield stress and hardening behaviors vary with strain rate was adopted. To reduce the huge amount of computing time, the modeling range of ice and ship structure were restricted to the confined region of interest. Under the various scenario of ice-ship hull collision, the structural behavior of hull panels and failure modes of ice were examined by nonlinear FE analysis technique.

Keywords

Ice collision simulation;Fresh water ice;Sea ice;Strain rate effect;LS-DYN

References

  1. Bishop, R. & Price, W., 1979. Hydroelasticity of Ships. Cambridge University Press.
  2. Carney, Kelly S. Benson, David J. DuBois, Paul. & Lee, Ryan., 2006. A Phenomenological High Strain Rate Model with Failure for Ice. International Journal of Solids and Structures, 43, pp. 7820-7839. https://doi.org/10.1016/j.ijsolstr.2006.04.005
  3. Derradji-Aouat, A. Sinha, N.K. & Evgin, E., 2000. Mathematical Modelling of Monotonic and Behaviour of Fresh Water Columnar Grained S-2 Ice. Cold Regions Science and Technology, 31, pp.59-81. https://doi.org/10.1016/S0165-232X(00)00005-7
  4. DNV, 2006. Iceberg Collision Scenario, Det Norske Veritas Report, Report No. : 2006-0672.
  5. Han, S.K. Park, Y.I. & Che, J.S., 2008. Structure risk analysis of a GTT NO96 membrane type LNG carrier in baltic ice operations. Proceedings of IMechE 2008. vol. 222 no. 4 Institution of Mechanical Engineers, pp.179-192 20 May 2008.
  6. Jones, S., 2006. Comparison of the Strength of Iceberg and Other Freshwater Ice and the Effect of Temperature, PERD/CHC Report 20-83 TR-2006-07, Canada:NRC.
  7. Kolari, K. Kuutti, J. & Kurkela, J., 2009. FE-simulation of continuous ice failure based on model update technique. Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions, 9-12 June 2009, Luleå: Sweden
  8. Kujala, P. Suominen, M. & Jalonen, R., 2007a. Increasing the Safety of Icebound Shipping, Final Scientific Report: Volume 1, Helsinki University of Technology, Ship Laboratory.
  9. Kujala, P., Suominen, M. and Jalonen, R., 2007b. Increasing the Safety of Icebound Shipping, Final Scientific Report: Volume 2, Helsinki University of Technology, Ship Laboratory.
  10. Lee, S.G. Lee, J.S. Baek, Y.H. & Paik, J.K., 2009. Development of full scale iceberg-membrane type LNG carrier collision simulation technique. Proceeding of the Annual Spring Meeting, the Society of Naval Architecture of Korea, Changwon, 28-29 May 2009. pp.1263-1304.
  11. LSTC, 2007 LS-DYNA Keyword User's Manual, volume1, Version 971.
  12. Nho, I.S. Yun, Y.M. Park, M.J. Oh, Y.T. & Kim, S.C., 2014. Structural Safety Assessment of Mark III Membrane Type LNG CCS under Ice Collision. Journal of Ocean Engineering and Technology, 28(2), pp.126-132. https://doi.org/10.5574/KSOE.2014.28.2.126
  13. Wang, Y.S., 1982. A Rate-Dependent stress-strain relationship for sea ice. Proceedings of the 1st International Offshore Mechanics and Arctic Engineering Symposium, Vol.2.

Acknowledgement

Grant : 해양안전기술개발

Supported by : 한국해양과학기술원 부설 선박해양플랜트연구소