Abstract




 
   

Vol. 18, No. 3 (August 2005) 219-228   

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  THE EFFECT OF ADDED MASS FLUCTUATION ON HEAVE VIBRATION OF TLP
 
M. R. Tabeshpour, A. A. Golafshani

Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
tabesh_mreza@yahoo.com, golali@sharif.edu

M. S. Seif

Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
seif@sharif.edu


 
( Received: July 16, 2004 )
 
 

Abstract    The resulting motion in waves can be considered as a superposition of the motion of the body in still water and the forces on the restrained body. In this study the effect of added mass fluctuation on vertical vibration of TLP in the case of vibration in still water for both free and forced vibration subjected to axial load at the top of the leg is presented. This effect is more important when the amplitude of vibration is large. Also this is important in fatigue life study of tethers. The structural model used here is very simple. Perturbation method is used to formulate and solve the problem. First and second order perturbations are used to solve the free and forced vibration respectively.

 

Keywords    Added Mass Fluctuation, Wave, TLP, Heave Vibration, Perturbation Method

 

References   

1. Faltinsen, O. M., Van Hooff, R. W., Fylling, I. J., Teigen, P. S. "Theoretical and Experimental Investigations of Tension Leg Platform Behavior", Proceedings of BOSS 1, (1982), 411-423.

2. Siddiqui N. A., and Ahmad S., "Fatigue and Fracture Reliability of TLP Tethers under Random Loading", Journal of Marine Structures, Vol. 14, (2001), 331-352.

3. Teigen, P. S., "The Response of a Tension Leg Palatform in Short-Crested Waves", Proceedings of the Offshore Technology Conference, OTC No. 4642, (1983), 525-532.

4. Jain, A. K., "Nonlinear Coupled Response of Offshore Tension Leg Platforms to Regular Wave Forces", Ocean Engineering, Vol. 24, No. 7, (1997), 577-592.

5. Ahmad S., "Stochastic TLP Response under Long Crested Random Sea", Journal of Computers and Structures, Vol. 61, No. 6, (1996), 975-993.

6. Chandrasekaran, S., Jain, A. K., "Nonlinear Dynamic Behaviour of Offshore Tension Leg Platforms under Regular Wave Lloads. Ocean Engineering Vol. 28, No. 12, (2001).

7. Tabeshpour, M. R., Golafshani, A. A., and Seif, M. S., "Simple Models for Heave Response of Tension Leg Platform under Harmonic Vertical Load", 8th International Conference of Mechanical Engineering, Tarbiat Modares University, (2004), Iran.

8. Tabeshpour, M. R., Golafshani, A. A., and Seif, M. S., "The Effect of Added Mass Fluctuation on Vertical Motion of Moored Sstructures" 8th International Conference of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran, (2004), (in Farsi).

9. Tabeshpour, M. R., Seif, M. S. and Golafshani, A. A., "Vertical Response of TLP with the Effect of Added Mass Fluctuation", 16th Symposium on Theory and Practice of Shipbuilding, SORTA, (2004), Crovatia.

10. Nayfeh, A. H., Perturbation Methods, New York: John Wiley & Sons, (1973).

11. Kevorkian, J., and Cole, J. D., Perturbation Methods in Applied Mathematics, New York: Springer-Verlag, (1981).

12. Journee, J. M. J., and Massie, W. W., Offshore Hydromechanics, Delft University of Technology, (2001).


 





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