Abstract
This paper describes the linearized and nonlinear dynamic response of a tension leg platform (TLP) to random waves and current forces. The forcing term of the equation of motion is inherently nonlinear due to the nonlinear drag force. Two analysis procedures are used: nonlinear time domain analysis and linear frequency domain analysis. For the nonlinear analysis, the random wave particle velocities and accelerations are simulated for a given wave spectrum. The nonlinear equation of motion is then integrated directly to obtain the system response statistics. For the linear frequency domain analysis, the nonlinear drag force is linearized through an introduction of linearization coefficients. The main objective of this paper is to investigate the effect of the structural damping and wave parameters on both nonlinear and linear dynamic response of the TLP by parametric studies. The results of stochastic nonlinear and linear dynamic response of the TLP, with and without the presence of current, are presented and compared.
Similar content being viewed by others
References
Albrecht, H. G., Koenig, D., and Kokkinowrachos, K., ‘Non-linear dynamic analysis of tension leg platform for medium and greater depth’, Offshore Technology Conference, Paper No. 3044, 1978, 7–15.
Beynet, P. A., Berman, M. Y., and Von Aschwege, J. K., ‘Motion, fatigue, and reliability characteristics of a vertical moored platform’, Offshore Technology Conference, Paper No. 3304, 1978, 2203–2212.
Botelho, D. L. R., Finnigan, T. D., Petrauskas, C., and Liu, S. V. ‘Model test evaluation of a frequency domain procedure for extreme surge response prediction of tension leg platform’, Offshore Technology Conference, Paper No. 4658, 1984, 105–112.
Deleuil, G. E., Des Deserts, L. D., Doris, C. G., and Shive, A., ‘A new method for frequency domain analysis of offshore structures: composition with time domain analysis’, Offshore Technology Conference, Paper No. 5303, 1986, 103–110.
Denis, J.-P. F. and Heaf, N. J., ‘A comparison between linear and nonlinear response of a proposed tension leg production platform’, Offshore Technology Conference, Paper No. 3555, 1979, 1743–1754.
Datta T. K. and Jain A. K., ‘Nonlinear surge response of a tension leg platform to random wave forces’, Eng. Struct. 10, 1988, 204–210.
Jefferys E. R. and Patel M. H., ‘Dynamic analysis models of tension leg platforms’, Tran. ASME J. Energ. Res. Tech. 104, 1982, 217–223.
Oran, C., ‘Overall dynamic characteristics of tension leg platform’, Offshore Technology Conference, Paper No. 4640, 1983, 507–516.
Spanos P. D. and Agarwal V. K., ‘Response of a simple tension leg platform model to wave forces calculated at displaced position’, Tran. ASME J. Energ. Res. Tech. 106, 1984, 437–443.
Yashima, N., ‘Experimental and theoretical study of a tension leg platform in deep water’, Offshore Technology Conference, Paper No. 2690, 1976, 849–856.
Yoshida K., Ozaki M., and Oka N., ‘Structural response analysis of tension leg platform’, Tran. ASME J. Energ. Res. Tech. 106, 1984, 10–17.
Berge, B. and Penzien, J., ‘Three-dimensional stochastic responses of offshore towers to wave forces’, Offshore Technology Conference, Paper No. 2050, 1974, 173–190.
Ertas A., ‘Linearization technique for probabilistic riser frequency domain analysis’, ASME J. Energ. Res. Tech. 108, 1986, 292–296.
Krolikowski, L. P. and Gay, T. A., ‘An improved linearization technique for frequency domain riser analysis’, Offshore Technology Conference, Paper No. 3777, 1980, 341–353.
Langley R. S. and Kirk C. L., ‘Random dynamic analysis of an offshore single anchor leg storage system’, Applied Ocean Res. 4, 1982, 232–236.
Langley R. S., ‘The linearization of three-dimensional drag force in random sea with current’, Applied Ocean Res. 6, 1984, 126–131.
Malhorta A. K. and Penzien J., ‘Nondeterministic analysis of offshore structures’, ASCE J. Eng. Mech. 96, 1970, 985–1003.
Wu, S. C. and Ray, J., ‘The effects of current on dynamic response of offshore platforms’, Offshore Technology Conference, Paper OTC 2540, 1976, 185–196.
Ertas A. and Lee J.-H., ‘Stochastic response of tension leg platform to wave and current forces’, Tran. ASME J. Energ. Res. Tech. 11, 1989, 221–230.
Lee C.-K., ‘Dynamic response of tension leg platform in a random sea’, Masters of Engineering Report, Texas A&M University, College Station, Texas, 1981.
Newland D. E., An Introduction to Random Vibration and Spectral Analysis, Longman, London, 1984.
Lee W. T. and Bales S. L., ‘A modified JONSWAP spectrum development only on wave height and period’, Report No. SPD-0918–01, David W. Taylor Naval Ship Research and Development Center, MD, 1980.
Tung C. C. and Huang N. E., ‘Influence of current on statistical properties of waves’, J. Waterways, Harbors and Coastal Engrg. 100, No. WW4, 1974, 267–278.
Shinozuka M., Fang S.-L., and Nishitani A., ‘Time-domain structural response simulation in a short-crested sea’, Tran. ASME J. Energ. Res. Tech. 101, 1979, 270–275.
Dhatt G. and Touzot G., The Finite Element Method Displayed, Wiley, New York, 1984.
Ochi M. K., ‘On the Prediction of extreme values’, J. Ship Res. 17(1), 1973, 23–27.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ertas, A., Ekwaro-Osire, S. Effect of damping and wave parameters on offshore structure under random excitation. Nonlinear Dyn 2, 119–136 (1991). https://doi.org/10.1007/BF00053832
Issue Date:
DOI: https://doi.org/10.1007/BF00053832