Authors

1 Center of Excellence in Hydrodynamics and Dynamics of Marine Vehicles, Mechanical Engineering Department, Sharif University of Technology

2 Civil Engineering Department, Sharif University of Technology

3 Mechanical Engineering Department, Sharif University of Technology

Abstract

Because of fluctuation in leg tension, pitch motion is very effective fatigue and life safety of leg elements in tension leg structures (TLSs). In this paper an exact solution for pitch vibration of a TLS interacting with ocean wave is presented. The legs of TLP are considered as elastic springs. The flow is assumed to be irrotational and single-valued velocity potentials are defined. The effects of radiation and scattering are considered in the boundary value problem. Because of linear behavior of legs during wave excitation, ignoring coupling effects with other degrees of freedom, the analytical solution of pitch response has good agreement with the real behavior of the structure.

Keywords

Jui-Jung, L.; Yun-Fu, H.; Hung-Wei, L., (2004). Nonlinear Pitch Motion Identification and Interpretation of a Tension Leg Platform. Journal of Marine Science and Technology, 12 (4), 309-318.
Lee, C. P.; Lee, J. F., (1993). Wave Induced Surge Motion of a Tension Leg Structure. Ocean Engineering, 20 (2), 171–186.
Lee, C. P., (1994). Dragged Surge Motion of a Tension Leg Structure. International Journal of Ocean Engineering, 21 (3), 311-328.
Lee, H. H.; Wang, P. W.; Lee, C. P., (1999). Dragged Surge Motion of Tension Leg Platforms and Strained Elastic Tethers. Ocean Engineering, 26 (2), 579–594.
Tabeshpour, M. R.; Golafshani, A. A.; Seif, M. S., (2004). Simple Models for Heave Response of TLP under Harmonic Vertical Load. Proc 8th International Conference on Mechanical Engineering, ISME-2004.  
Tabeshpour, M. R.; Golafshani, A. A.; Seif, M. S., (2006a). Second order perturbation added mass fluctuation on vertical vibration of TLP. Marine Structures, 19 (4), 271–283.  
Tabeshpour, M. R.; Golafshani, A. A.; Ataie Ashtiani, B.; Seif, M. S., (2006b). Analytical Solution of Heave Vibration of Tension Leg Platform. International Journal of Hydrology and Hydromechanics, 54 (3), 280-289.
Tabeshpour, M. R.;  Ataie Ashtiani, B.;  Seif,  M. S.; Golafshani, A. A., (2006). Wave Interaction Pitch Response of Tension Leg Structures", 13th International Congress on Sound and Vibration, Austria, Vienna.