Use of Quadratic Transfer Functions to Predict Response of Tension Leg Platforms
Publication: Journal of Engineering Mechanics
Volume 122, Issue 9
Abstract
Higher-order nonlinear transfer functions are applied to model the computed nonlinear responses obtained from the dynamic analysis of a tension leg platform (TLP). Under the nonlinear wave-loading condition considered in the present study, the horizontal motion of TLP exhibits a significant amount of response components at frequencies that are outside the range of the excitation frequencies, but which are near the natural frequency of the TLP. Higher-order nonlinear transfer functions based on a Volterra series representation are used to model these nonlinear responses that cannot be properly represented with a linear transfer function only. The transfer function model clearly shows the degrees of nonlinearity of these responses as strongly quadratic. To examine the applicability of the nonlinear transfer functions, both the quadratic transfer functions obtained from a wave spectrum and the corresponding responses were applied to other wave spectra with different magnitude of wave power, and the results are discussed.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Brigham, E. O. (1988). The fast Fourier transform and its applications . Prentice-Hall, Inc., Englewood Cliffs, N.J.
2.
Chakrabarti, S. K. (1987). Hydrodynamics of offshore structure . Computational Mechanics Publications, Southampton, U.K.
3.
Clough, R. W., and Penzien, J. (1975). Dynamics of structures . McGraw-Hill Book Co., Inc., New York, N.Y.
4.
Donley, M. G., and Spanos, P. D. (1990). Dynamic analysis of non-linear structures by the method of statistical quadratization . Lecture Notes in Engineering, Springer-Verlag, KG, Berlin, Germany.
5.
Kim, K. I., Powers, E. J., Ritz, C. P., Miksad, R. W., and Fischer, F. J. (1987). “Modeling of the nonlinear drift oscillations of moored vessels subject to non-Gaussian random sea-wave excitation.”IEEE J. Oceanic Engrg., OE-12, 568–575.
6.
Kim, K. I., and Powers, E. J. (1988). “A digital method of modeling quadratically nonlinear systems with a general random input.”IEEE Trans. on Software Engrg., ASSP-36, 1758–1769.
7.
Kim, S. B., Powers, E. J., Miksad, R. W., Fischer, F. J., and Hong, J. Y. (1989). “Spectral decomposition of nonlinear TLP sway response to non-Gaussian irregular seas.”Proc., of the 21st Annu. Offshore Technol. Conf., OTC 6134, Houston, Tex., 123–128.
8.
Mekha, B. B. (1994). “Non-linear dynamic response of tension leg platforms.”OTRC Rep. No. 8/94-B-58-75, Offshore Technology Research Center, Univ. of Texas at Austin, Austin, Tex.
9.
Nam, S. W. (1990). “Application of higher-order spectral analysis to nonlinear system identification,” PhD dissertation, Univ. of Texas at Austin, Austin, Tex.
10.
Paik, I. (1994). “Nonlinear dynamic behavior of offshore structures,” PhD dissertation, Univ. of Texas at Austin, Austin, Tex.
11.
Volterra, V. (1959). Theory of functionals and of integral and integro-differential equations . Dover Publications, New York, N.Y.
12.
Weggel, D., and Roesset, J. M. (1994). “Vertical hydrodynamic forces on truncated cylinders.”Proc., of the 4th Int. Offshore and Polar Engrg. Conf., ISOPE-94, Osaka, Japan, 210–217.
13.
Wheeler, J. D. (1969). “Method for calculating forces produced by irregular waves.”Proc., of the 1st Offshore Technol. Conf., OTC 1006, Houston, Tex., 171–182.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 122 • Issue 9 • September 1996
Pages: 882 - 889
Copyright
Copyright © 1996 American Society of Civil Engineers.
History
Published online: Sep 1, 1996
Published in print: Sep 1996
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.