engleski

Floater-tether semi-coupled dynamic response analysis of tension leg platforms

Mathematical model for the uncoupled floater- tether dynamic response analysis of floating tethered bodies (e.g. Tension Leg Platforms, Floating Offshore Wind Turbines) is extended to account for the nonlinear restoring stiffness due to the influence of mooring lines on the floating body dynamics. Also, a simple approximation of the inertia and viscous effects of tethered mooring lines is also taken into account resulting in a computationally inexpensive semi-coupled floater- tether mathematical model. Model is validated in the case of ISSC TLP in medium range depths using the fully coupled FEM model (theory of rod) taking into account tethered mooring lines deformations. Validation analysis includes static displacements and free decay tests. Time domain simulation is done by mapping linear frequency domain hydrodynamics to time domain using the Cummins integral approach, utilizing the HYDROSTAR potential flow code to determine the hydrodynamic reaction forces. Some useful results are presented and discussed.

semi-coupled analysis; nonlinear restoring stiffness; time domain; tension leg platform

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