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Numerical Analysis on Triceratops Restraining System: Failure Conditions of Tethers

Authors: Srinivasan Chandrasekaran, Manda Hari Venkata Ramachandra Rao


Increase in the oil and gas exploration in ultra deep-water demands an adaptive structural form of the platform. Triceratops has superior motion characteristics compared to that of the Tension Leg Platform and Single Point Anchor Reservoir platforms, which is well established in the literature. Buoyant legs that support the deck are position-restrained to the sea bed using tethers with high axial pretension. Environmental forces that act on the platform induce dynamic tension variations in the tethers, causing the failure of tethers. The present study investigates the dynamic response behavior of the restraining system of the platform under the failure of a single tether of each buoyant leg in high sea states. Using the rain-flow counting algorithm and the Goodman diagram, fatigue damage caused to the tethers is estimated, and the fatigue life is predicted. Results shows that under failure conditions, the fatigue life of the remaining tethers is quite alarmingly low.

Keywords: Fatigue life, Failure analysis, PM spectrum, rain flow counting, triceratops.

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[1] S. Chandrasekaran and A. K. Jain, "Dynamic behavior of the square and triangular offshore tension leg platforms under regular wave loads," Ocean Engineering,29(3), pp. 279-313, 2002.
[2] C. N. White, R. W. Copple and C. Capanoglu, "Triceratops: an effective platform for developing oil and gas fields in deep and ultra-deep water.," in The fifteenth international offshore and polar engineering conference. International society of offshore and polar engineers, Seoul, 2005.
[3] S. Chandrasekaran and M. Seeram, "Stability studies on an offshore triceratops," International Journal of Innovative Research and Development. (ISSN 2278–0211), vol. 1(10), pp. 398-404., 2012.
[4] S. Chandrasekaran and M. Nannaware, "Response analyses of the offshore triceratops to seismic activities," Ships and Offshore Structures, vol. 9(6), pp. 633-642, 2013.
[5] S. Chandrasekaran, S. Mayank, and A. Jain, "Dynamic Response Behaviour of Stiffened Triceratops Under Regular Waves: Experimental Investigations," in In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering, 2015, May.
[6] S. Chandrasekaran and S. Madhuri, "Dynamic response of offshore triceratops: Numerical and Experimental investigations," Ocean Engineering, pp. 109, 401-409, 2015.
[7] S. Chandrasekaran and P. A. Kiran, "Mathieu stability of offshore triceratops under postulated failure," Ships and Offshore Structures, pp. 13(2), 143-148, 2018.
[8] S. Chandrasekaran and R. Nagavinodini, "Dynamic analyses and preliminary design of offshore triceratops in ultra-deep waters," Innovative Infrastructure Solutions, pp. 3(1), 16, 2018.
[9] D. V. Reddy and A. Swamidas, Essentials of Offshore Structures: Framed and Gravity Platforms, Boca Raton, CRC Press, 2013.
[10] "Interim Guidance on Hurricane Conditions in the Gulf of Mexico," May2007.(Online).Available: 002/api.2int-met.2007.pdf.
[11] Veritas and D. N., Fatigue design of offshore steel structures. DNV Recommended Practice, DNVGL - RP-C203,20, 2010.
[12] Adam. J. Sadowski, J. Michael Rotter, Thomas Reinke and Thomas Ummenhofer, "Statistical analysis of the material properties of selected structural carbon steels," Structural Safety, pp. 53, 26-35. 10.1016/j.strusafe.2014.12.002., 2015.