Dynamic analysis of a multi-column TLP floating offshore wind turbine with tendon failure scenarios

ABS TRACT This paper presents the design and dynamic analysis of a multi-column tension leg platform floating offshore wind turbine (TLP FOWT) with broken tendons. The proposed concept is based on a conventional Tri-Floater platform configuration but is especially optimized for an intermediate water depth of 60 m. Tendons are simulated to be broken at a specific time of interest. The hydrodynamic parameters and motion responses of the TLP FOWT have been calculated using the hydrodynamic analysis software WAMIT and ANSYS/AQWA. These parameters are then used in the simulation of coupled responses of the FOWT by the National Renewable Energy Laboratory's analysis suite of tool, FAST. The tendon failure has been investigated to examine the system per-formance under the accidental limit states (ALS) described in the design code DNV-RP-0286. A series of dynamic analysis under operational and extreme environmental conditions (with 12 different load cases) are carried out with the combination of wind and waves. The results demonstrate that the turbine is able to remain highly stable during the 3-h simulations conducted. The platform's response amplitude operators (RAOs) evaluated show good stability in heave and pitch. The tendon failures affected the FOWT's heave, pitch and roll motions, hence its natural frequencies, and the tension in the non-broken tendons. The average tensile force in the line adjacent to the broken line is found to be doubled, while the safety factors as specified in DNV-OS-E301 are remained within the recommended value. This paper provides further insights into the hydrodynamics of the multi-column TLP FOWT, with the aim to provide new information to the offshore wind research community.

Automated summary

This paper presents the design and dynamic analysis of a multi-column tension leg platform floating offshore wind turbine with broken tendons. The study examines the impact of tendon failure on the system performance, demonstrating the turbine's stability under various environmental conditions.