Research Papers: Ocean Renewable Energy

Preliminary Assessment of the Importance of Platform–Tendon Coupling in a Tension Leg Platform

[+] Author and Article Information
Meyer Nahon

Department of Mechanical Engineering,
McGill University,
Quebec H3A 2K6, Canada

Frederick Driscoll

National Renewable Energy Laboratory,
Golden, CO 80401

Contributed by the Ocean, Offshore, and Arctic Engineering Division of ASME for publication in the JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING. Manuscript received May 25, 2011; final manuscript received October 22, 2012; published online May 24, 2013. Assoc. Editor: Ron Riggs.

J. Offshore Mech. Arct. Eng 135(3), 031901 (May 24, 2013) (11 pages) Paper No: OMAE-11-1046; doi: 10.1115/1.4023795 History: Received May 25, 2011; Revised October 22, 2012

This paper presents performance metrics that can be used to evaluate the response sensitivity of a tension leg platform (TLP) to its tendons. An uncoupled TLP model ignores the intrinsic dynamics and environmental loads on the cables by treating each tendon as an ideal massless spring. A coupled TLP system, in contrast, considers the effects of distributed mass and drag along the tendon. Under certain operating conditions, an uncoupled dynamics model can produce results comparable to its coupled counterpart. This paper defines the conditions under which it is acceptable to model a TLP tendon as a linear spring, as opposed to one that considers the cable dynamics. The analysis is performed in the frequency domain and, for generality, the results are nondimensionalized. The findings indicate that a more elaborate set of conditions than the platform–to–cable mass ratio must be satisfied for the two models to provide similar results. To conclude this study, two simulations are performed and compared against the performance metrics derived in this paper.

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Paulling, J. R., 1971, “Analysis of the Tension Leg Platform,” Society of Petroleum Engineers, September, Vol. 1, No. 3, pp. 285–294.
Chandrasekaran, S., and Jain, S. K., 2002, “Dynamic Behaviour of Square and Triangular Offshore Tension Leg Platform Under Regular Wave Loads,” Ocean Eng., 29, pp. 279–313. [CrossRef]
Musial, W., Butterfield, S., and Boone, A., 2004, “Feasibility of Floating Platform Systems for Wind Turbines,” 23rd ASME Wind Energy Symposium, Reno, NV.
Low, Y. M., 2009, “Frequency Domain Analysis of a Tension Leg Platform With Statistical Linearization of the Tendon Restoring Force,” Marine Struct., 22, pp. 480–503. [CrossRef]
Jonkman, J. M., 2009, “Dynamics of Offshore Floating Wind Turbines — Model Development and Verification,” Wind Energy, 12, pp. 459–492. [CrossRef]
Sclavounos, P. D., Lee, S., DiPietro, J., Potenza, G., Caramuscio, P., and De Michele, G., 2010, “Floating Offshore Wind Turbines: Tension Leg Platform and Taught Leg Buoy Concepts Supporting 3-5 MW Wind Turbines,” European Wind Energy Conference EWEC 2010, Warsaw, Poland, April 20–23.
American Petroleum Institutute, 1997, Recommended Practices for Planning, Designing, and Constructing Tension Leg Platforms, Document No. API Recommended Practice 2T, American Petroleum Institute, Washington, D.C.
Angelides, D. C., Chen, C., and Will, S. A., 1982, “Dynamic Response of Tension Leg Platform,” Proceeding of BOSS 1982, Cambridge, MA, pp. 100–120.
Malaeb, D. A., 1982, “Dynamic Analysis of a Tension Leg Platform,” Ph.D. thesis, Texas A&M University, College Station, TX.
Jefferys, E. R., and Patel, M. H., 1982, “On the Dynamics of Taut Mooring Systems,” Eng. Struct., 4(1), pp. 37–43. [CrossRef]
Venkataramana, K., 1994, “Earthquake Response of Tension–Leg-Platforms in Steady Currents,” Earthquake Eng. Struct. Dyn., 23(1), pp. 63–74. [CrossRef]
Catterjee, P. C., Das, P. K., and Faulkner, D., 1997, “A Hydro–Structural Analysis Program for TLPS,” Ocean Eng., 24(4), pp. 313–334. [CrossRef]
Ran, Z., Kim, M. H., and Zheng, W., 1999, “Coupled Dynamic Analysis of a Moored Spar in Random Waves and Currents (Time Domain versus Frequency Domain Analysis),” 17th International Symposium and Exhibit on Offshore Mechanics and Arctic Engineering, July 5–9, Lisbon, Portugal, pp. 194–200.
Mekha, B. B., Johnson, C. P., and Roesset, J. M., 1996, “Implications of Tendon Modeling on Nonlinear Response of TLP,” J. Struct. Eng., 122(2), pp. 142–149. [CrossRef]
Oran, C., 1983, “Overall Dynamic Characteristics of Tension Leg Platform,” 15th Annual Offshore Technology Conference, May 2–5, Houston, TX, pp. 507–513.
Datta, T. K., and Jain, A. K., 1988, “Nonlinear Surge Response of a Tension Leg Platform to Random Wave Forces,” J. Eng. Struct., 10, pp. 204–210. [CrossRef]
Ottaviano, E., and Castelli, G., 2010, “A Study on the Effects of Cable Mass and Elasticity in Cable–Based Parallel Manipulators,” ROMANSY 18 Robot Design, Dynamics and Control CISM International Center for Mechanical Sciences, Vol. 524, pp. 149–156.
Grosenbaugh, M. A., 1995, “On the Dynamics of Oceanographic Surface Moorings,” Ocean Eng., 23(1), pp. 7–25. [CrossRef]
Driscoll, F. R., 1999, “Dynamics of a Vertically Tethered Marine Platform,” Ph.D. thesis, University of Victoria, Victoria, BC.
Nordgren, A. P., 1987, “Analysis of High-Frequency Vibration of Tension Leg Platforms,” J. Offshore Mech. Artic Eng., 109(2), pp. 119–125. [CrossRef]
Dong, Y., Xie, G., and Lou, Y. K., 1992, “Stability of Vortex-Induced Oscillations of Tension Leg Platform Tethers,” Ocean Eng., 19(6), pp. 555–571. [CrossRef]
Caughey, T. K., 1963, “Equivalent Linearization Techniques,” J. Acoust. Soc. Am., 35(11), pp. 1706–1711. [CrossRef]
French, A. P., 1971, Vibrations and Waves, W. W. Norton and Company, New York.
Masciola, M. D., Nahon, M., and Driscoll, F. R., 2012, “Dynamics Analysis of a Coupled and an Uncoupled Tension Leg Platform” (submitted).
Farlow, S. J., 1982, Partial Differential Equations for Scientists and Engineers, John Wiley and Sons, New York.
Newman, J. N., 1977, Marine Hydrodynamics, The Massachusetts Institute of Technology Press, Cambridge, MA.
Chen, X., Ding, Y., Zhang, J., Liagre, P., Niedzwecki, J., and Teigen, P., 2006, “Coupled Dynamic Analysis of a Mini TLP: Comparison With Measurements,” Ocean Eng., 33, pp. 93–117. [CrossRef]


Grahic Jump Location
Fig. 2

In the coupled analytical TLP model, each tendon is permitted to deform in the manner pictured. u(z, t) represents the cable stretch in the longitudinal direction, and w(z, t) is a displacement in a direction normal to the z-axis and represents transverse motions.

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Fig. 1

The analytical models derived in this work assume the TLP geometry and boundaries depicted in this figure. Variable Tx(t) is the dynamic tension due to transverse oscillations, and it is aligned with the x-axis. For clarity, the profile for one tendon is shown, but it is implied that remaining tendons oscillate in a similar manner.

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Fig. 4

When Λi is a small number, the platform senses the longitudinal/transverse tendon motions. In the opposite case, the mooring line provides additional damping in the platform.

Grahic Jump Location
Fig. 3

The nondimensionalized TLP surge and heave responses of a TLP in (a) 600 ms depth and (b) 1200 ms depth. This figure depicts both the coupled analytical model G˜x,z(s˜) and the uncoupled analytical model H˜x,z(s˜).

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Fig. 5

The above figures illustrate results for weakly coupled TLP in 600 ms water depth. Although differences between the uncoupled and coupled are small when comparing the time histories, the PSD plots help to elucidate the source of the model differences. In the pitch PSD plot, a difference between models emerges at the pitch natural frequency since Ωθ has approached a critical threshold.

Grahic Jump Location
Fig. 6

Simulation results for a TLP in 1200 ms water depth. In this example, the coupled TLP response is more receptive to the cable dynamics. Differences between the coupled and uncoupled models are attributable to (1) the stiffness condition being violated, (2) the platform sensing the mooring drag force, and (3) the cable natural frequencies being excited.



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