Ocean Systems Engineering

  • 제8권3호
  • /
  • Pages.345-360
  • /
  • 2018
  • /
  • 2093-6702(pISSN)
  • /
  • 2093-677X(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Mathieu stability of offshore Buoyant Leg Storage & Regasification Platform

  • Chandrasekaran, S. (Department of Ocean Engg., Indian Institute of Technology Madras) ;
  • Kiran, P.A. (Department of Ocean Engg., Indian Institute of Technology Madras)
  • 투고 : 2018.02.27
  • 심사 : 2018.07.27
  • 발행 : 2018.09.25
⟨ 이전 논문 다음 논문 ⟩

초록

Increasing demand for large-sized Floating, Storage and Regasification Units (FSRUs) for oil and gas industries led to the development of novel geometric form of Buoyant Leg Storage and Regasification Platform (BLSRP). Six buoyant legs support the deck and are placed symmetric with respect to wave direction. Circular deck is connected to buoyant legs using hinged joints, which restrain transfer of rotation from the legs to deck and vice-versa. Buoyant legs are connected to seabed using taut-moored system with high initial pretension, enabling rigid body motion in vertical plane. Encountered environmental loads induce dynamic tether tension variations, which in turn affect stability of the platform. Postulated failure cases, created by placing eccentric loads at different locations resulted in dynamic tether tension variation; chaotic nature of tension variation is also observed in few cases. A detailed numerical analysis is carried out for BLSRP using Mathieu equation of stability. Increase in the magnitude of eccentric load and its position influences fatigue life of tethers significantly. Fatigue life decreases with the increase in the amplitude of tension variation in tethers. Very low fatigue life of tethers under Mathieu instability proves the severity of instability.

키워드

참고문헌

  1. Adrain, B. and Pulido, R.L. (2013), Ship hydrostatics and Stability, Butterworth-Heinemann.
  2. Bowman, F. (1958), Introduction to Bessel functions. Dover, New York.
  3. Chandrasekaran, S. (2015), Advanced Marine structures, CRC Press, Florida, ISBN 9781498739689.
  4. Chandrasekaran, S. (2016a), Offshore structural engineering: Reliability and Risk Assessment. CRC Press, Florida, ISBN:978-14-987-6519-0.
  5. Chandrasekaran, S. (2017), Dynamic analysis and design of ocean structures, Springer, 2nd Ed., Singapore.
  6. Chandrasekaran, S. and Jain, A. (2016), Ocean structures: Construction, Materials and Operations, CRC Press, Florida, ISBN: 978-14-987-9742-9.
  7. Chandrasekaran, S. and Kiran, P.A. (2017), "Mathieu stability of offshore triceratops under postulated failure", Ship. Offshore Struct., 13(2), 143-148
  8. Chandrasekaran, S. and Lognath, R.S. (2017), "Dynamic analyses of Buoyant leg Storage and Regasification platforms: Numerical studies", J. Mar. Syst. Ocean Tech., 12(2), 39-48. https://doi.org/10.1007/s40868-017-0022-6
  9. Chandrasekaran, S. and Lognath, RS. (2015), "Dynamic analyses of Buoyant Leg Storage Regasification Platform (BLSRP) under regular waves: Experimental investigations", Ship. Offshore Struct., 12(2), 171-181.
  10. Chandrasekaran, S. and Madhuri, S. (2012a), "Free vibration response of offshore triceratops: Experimental and analytical investigations", Proceedings of the 3rd Asian Conf. on Mech. of Functional Materials and Struct., 8-9 Dec, New Delhi.
  11. Chandrasekaran, S. and Madhuri, S. (2012b), "Stability studies on offshore triceratops", Proceedings of the Tech Samudhra Int. Conf. on Tech. of Sea, Indian Maritime University, Vishakapatnam, India, 1(10), 398-404.
  12. Chandrasekaran, S., Chandak, N.R. and Gupta, A. (2006), "Stability analysis of TLP tethers", Ocean Eng., 33(3-4), 471-482. https://doi.org/10.1016/j.oceaneng.2005.04.015
  13. Chandrasekaran, S., Lognath, R.S. and Jain, A. (2015), "Dynamic analysis of buoyant leg storage and regasification platform under regular waves", Proceedings of the 34th Int. Conf. on Ocean, Offshore and Arctic Engineering, St. John's, NL, Canada, May 31-June 5.
  14. Chandrasekaran, S., Madhuri, S. and Gaurav, A.K. (2010), "Dynamic response of offshore triceratops under environmental loads", Proceedings of the Int. Conf. of Marine Tech., 11-12, Dec, Dhaka, Bangladesh.
  15. Chandrasekaran, S., Mayank, S. and Jain, A. (2015), "Dynamic response behavior of stiffened triceratops under regular waves: Experimental investigations", Proceedings of the 34th Int. Conf. on Ocean, Offshore and Arctic Engineering , St. John's, NL, Canada, May 31-June 5.
  16. Chandrasekaran, S., Sundaravadivelu, R., Pannerselvam, R. and Madhuri, S. (2011), "Experimental investigations of offshore triceratops under regular waves", Proceedings of the 30th Int. Conf. on Ocean, Offshore and Arctic Engg, Rotterdam, The Netherlands, 19-24th June.
  17. Chandresekaran, S., Madhuri, S. and Jain, A. (2013), "Aerodynamic response of offshore triceratops", Ship. Offshore Struct., 8(2), 123-140. https://doi.org/10.1080/17445302.2012.691271
  18. Copple, R.W. and Capanoglu, C.C. (1995), "Buoyant leg structure for development of marginal fields in deep water", Proceedings of the 5th Int. Offshore and Polar Engineering Conf., The Hague, The Netherlands, June 11-16.
  19. Goldstein, S. (1929), "Mathieu functions", Trans. Cambridge Philosophical Society, 23, 303-336.
  20. Haslum, H.A. and Faltinsen, O.M. (1999), "Alternative shape of spar platforms for use in hostile areas", Proceedings of the 31st Offshore Technology Conference, Houston, (OTC 10953).
  21. Hove, G.O. and Moan, T. (1995), "Fatigue and fracture reliability of TLP tether system before and after failure", Proceedings of the 7th ICASP, Applications of statics and Probabalilty, (1). Rotter-dam: Balkema.
  22. Ince, E.L. (1925), "Researches into the characteristic numbers of the Mathieu equation", Proc. Royal Society of Edinburgh, 46, 9-20.
  23. Jefferys, E.R. and Patel, M.H. (1982), "Dynamic analysis models of Tension Leg Platforms", J. Energ. Resour. Technol., 104, 217- 223. https://doi.org/10.1115/1.3230406
  24. Koo, B.J., Kim, M.H. and Randall, R.E. (2004), "Mathieu instability of a spar platform with mooring and risers", Ocean Eng., 31(17-18), 2175-2208. https://doi.org/10.1016/j.oceaneng.2004.04.005
  25. Mclachlan, N.W. (1947), Theory and application of Mathieu functions, Oxford university press.
  26. Patel, M.H. and Park, H.I. (1991), "Dynamics of tension leg platform tethers at low tension. part I - Mathieu stability at large parameters", Mar. Struct., 4(3), 257-273. https://doi.org/10.1016/0951-8339(91)90004-U
  27. Perrett, G.R. and Webb, R.M. (1980), "Tethered Buoyant platform production system", Proceedings of the 12th Annual Offshore Tech. Conf., 3881, Houston, Texas, 5-8th May.
  28. Rho, J.B. and Choi, H.S. (2004), "Vertical motion characteristics of truss spars in waves", International Society of Offshore and Polar Engineers, 662-665
  29. Rho, J.B., Choi, H.S., Lee, W.C., Shin, H.S. and Park, I.K. (2002), "Heave and pitch motion of a spar platform with damping plate", Proceedings of the 12th International Offshore and Polar Engineering Conference, Kitakyshu.
  30. Rho, J.B., Choi, H.S., Lee, W.C., Shin, H.S. and Park, I.K. (2003), "An experimental study for mooring effects on the stability of spar platform", Proceedings of the 13th International Offshore and Polar Engineering Conference, Honolulu, HI.
  31. Rho, J.B., Choi, H.S., Shin, H.S. and Park, I.K. (2005), "A study on Mathieu-type instability of conventional spar platform in regular waves", Int. Soc. Offshore Polar Engineers, 15(2), 104-108
  32. Siddiqui, N.A. and Suhail, A. (2001), "Fatigue and fracture reliability of TLP tethers under random loading", Mar. Struct., 14(3), 331-352. https://doi.org/10.1016/S0951-8339(01)00005-3
  33. Siddiqui. N.A. and Suhail, A. (2000), "Reliability analysis against progressive failure of TLP tethers in extreme tension", Reliab. Eng. Syst. Safe., 68(3), 195-205. https://doi.org/10.1016/S0951-8320(00)00008-9
  34. Simos, A.N. and Pesce, C.P. (1997), "Mathieu stability in dynamics of TLP tether considering variable tension along the length", T. Built Environ., 29, 175-186.
  35. White, C.N., Copple, R.W. and Capangolu, C. (2005), "Triceratops: An effective platform for development of oil and gas fields in deep and ultra-deep water", Proceedings of the 15th Int. Offshore and Polar Eng. Conf., Seoul, Korea, June 19-24.

피인용 문헌

  1. Aerodynamic and hydrodynamic force simulation for the dynamics of double-pendulum articulated offshore tower vol.32, pp.4, 2021, https://doi.org/10.12989/was.2021.32.4.341
  2. Aerodynamic and hydrodynamic force simulation for the dynamics of double-hinged articulated offshore tower vol.33, pp.2, 2018, https://doi.org/10.12989/was.2021.33.2.141