Journal of Korean Society of Coastal and Ocean Engineers (한국해안해양공학회지)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Two Dimensional Flexible Body Response of Very Large Floating Structures

거대 부체구조물의 2차원 유연체 해석 및 거동

  • Namseeg Hong (Civil Eng. Team, Engineering & Construction Group, Samsung Corporation)
  • Published : 1996.12.01
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Abstract

Two-dimensional flexible body analysis (hydroelasticity theory) is adopted to a very large floating structure that may be multimodule and extend in the longitudinal direction. The boundary-element method (BEM) and Green function method(GFM) are used to obtain the hydrodynamic coefficients. The structure is considered to be a flexible beam responding to waves in the vertical direction and a consistent formulation for the hydrostatic stiffness is derived. The resulting coupled equations of motion are solved directly. Two designs of the module connectors are considered: a rotationally-flexible hinge connector, and a rotationally-rigid connector Numerical examples are presented to an integrated system of semi-submersibles. The analysis provides basic motions and section forces, which are useful to develop an understanding of the fundamental modes of displacement and force amplitudes for which multi-module VLFSs must be designed. The results show that while the hinge connectors result in greater motion, the rigid connectors increase substantially the sectional moments.

2차원 유연체해석 이론(수탄성 이론)을 여러개의 단위체 연결로 이루어진 거대 부체구조물의 해석에 적용하였다. 동수역학적 계수를 구하기 위해 경계요소법과 그린함수법이 사용되었으며 부체자체는 연직방향으로 파랑에 반응하는 연체보로 정수역학적 탄성계수에 대한 운동을 고려하여 운동방정식이 유도된다. 두가지 다른 형식의 연결, 즉 회전강성을 가진 것과 강성을 무시한 핀 형식의 연결요소가 고려되며 반잠수한 부체에 대해 해석결과가 제시된다. 해석결과는 거대 부체구조물의 설계에 필요한 변위와 내력에 관한 개념을 제시한다. 또한 수치해석 결과에 따르면 부체의 움직임은 핀연결이 강성체 연결보다 더 크며 부체의 내력휨 응력은 강성체 연결에서 휠씬 더 크게 증가하였다.

Keywords

References

  1. Ph.D. dissertation, Department of Ocean Engineering, University of Hawaii Nonlinear wave and current loading on large OTEC pipe Andres,J.M.
  2. Hydroelasticity of ships Bishop,R.E.D.;Price,W.G.
  3. The boundary element method for engineering Brebbia,C.A.
  4. Int. Shipbldg. Prog. v.21 Comparison of ship motion theories with experiments for a container ship Flokstra,C.
  5. NSRDC Report 2375 Oscillation of cylinders in below the free surface of deep fluids Frank,W.
  6. Applied Ocean Research v.6 no.1 Interaction of oblique wave with an infinite cylinder Garrison,C.J.
  7. 5th Symp. on Naval Hydrodynamics The distribution of the hydrodynamic force on a heaving and pitching ship model in still water Gerritsma,J.;Beukelman,W.
  8. Proc. 3rd International Conf. on Structural Safety and Reliability Dynamic response of the Hood Canal floating bridge failure Hartz,B.J.
  9. J. Am. Soc. Naval Engrs. v.71 no.2 Hydroelasticity: A new naval science Heller,S.R.;Abramson,H.N.
  10. Communications on pure and applied mathematics v.3 On the motion of floating bodies Ⅱ John,F.
  11. Foundations of potential theory Kellog,O.D.
  12. NSRDC Report 3695 Added mass and damping coefficients of heaving twin cylinders in a free surface Lee,C.M.;Jones,H.;Bedel,J.W.
  13. The applied dynamics of ocean surface waves(2nd ed.) Mei,C.C.
  14. The theory of sound(2nd ed.) v.8 Rayleigh,L.
  15. Trans. SNAME v.78 Ship motions and sea loads Salvesen,N.;Tuck,E.O.;Faltinsen,O.
  16. Univ. of Hawaii, Seagrant, Tech. Rep. no.2 Theoretical investigations of optimization of the platform's seakeeping characteristics Seidl,L.
  17. Univ. of Hawaii, Segrant-CR-75-01, Tech. Rep. no.1 The winds, currents and waves at the suite of the Floating City of Waikiki St.Denis,M.
  18. Vibration problems in engineering(4th ed.) Timoshenko,S.P.;Young,D.H.;Weaver,W.
  19. Floating airport San Diego workshop USD
  20. Hundbuch der Physik, Band 9 Surface waves Wehausen,J.V.;Laitone,E.V.