Influence Of Tether Length In The Response Behavior Of Square Tension Leg Platform In Regular Waves

• Main Authors: El-Gamal, Amr R., Essa, Ashraf, Ismail, Ayman
• Format: Text
• Language: English
• Published: Zenodo 2013
• Subjects: Hydrodynamic wave forces; tension leg platforms; tethers length; wave characteristic.; Arctic; Indian
• Online Access: https://dx.doi.org/10.5281/zenodo.1089337; https://zenodo.org/record/1089337

The tension leg platform (TLP) is a vertically moored structure with excess buoyancy. The TLP is regarded as moored structure in horizontal plan, while inherit stiffness of fixed platform in vertical plane. In this paper, a numerical study using modified Morison equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between surge, sway, heave, roll, pitch and yaw degrees of freedom on the dynamic behavior of TLP's. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark’s beta integration scheme. The effect of tethers length and wave characteristics such as wave period and wave height on the response of TLP's was evaluated. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e. 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether length, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations about that is significantly dependent on tether length. : {"references": ["A. M. Abou-Rayan, Ayman A. Seleemah, and Amr R. El-gamal,\" Wave induced motions of a squared tension leg platform in deep waters\", Al-Azhar University Engineering Journal, Vol. 5, No. 1, \tDEC 2010, pp. 340-360.", "Bhattachatya, S.K., Anitha, J., Idichandy, V.G., \"Experimental and numerical study of coupled dynamic response of a mini-tension leg platform\", Journal of Offshore Mechanics and Arctic, Engineering, 126(4), 2004, pp.318\u2013330.", "Chandrasekaran, S. and Roy, A., \"Phase space study of offshore structures subjected to non-linear hydrodynamic loading\", Proceedings of the International Conference on Structural Engineering, Indian Institute of Science, Bangalore, SEC 2005.", "Chandrasekaran, S., Jain, A. K., Gupta, A., Srivastava, A., \"Response behaviour of triangular tension leg platforms under impact loading\", Ocean Engineering, Vol. 34, 2007, pp.45\u201353.", "Chandrasekaran, S., Jain, A. K., Gupta, A., \"Influence of wave approach angle on TLP's response\", Ocean Engineering, Vol. 34, 2007, pp. 1322\u20131327.", "Ketabdari, M. J. and Ardakani, H. A., \"Nonlinear response analysis of a sea star offshore tension leg platform in six degrees of freedom\", WIT Transactions on the Built Environment 84,2005.", "Kurian, V.J., Gasim, M.A., Narayanan, S.P., Kalaikumar, V., \"Parametric Study of TLPs Subjected to Random Waves\", ICCBT-C-19, pp. 213-222, 2008.", "Kurian, V.J., Gasim, M.A., Narayanan, S.P., Kalaikumar, V., \"Response of Square and Triangular TLPs Subjected to Random Waves\", ICCBT-C-12, 2008, pp. 133-140.", "Low, Y. M., \"Frequency domain analysis of a tension leg platform with statistical linearization of the tendon restoring forces\", Marine Structures, Vol. 22, 2009, 480\u2013503."]}