TRUSS TYPE LOWER STRUCTURE OF FLOATING OFFSHORE WIND TURBINE

摘要

With regard to a tension leg platform (TLP) lower structure applied to a floatable marine wind power generator, an existing column-type integral frame structure is affected by sea current and has increased resistance since seawater is in contact with a large area of external plates. That means external force is increased and the structural strength and motion performance of the lower structure are negatively affected. Also, the existing column-type integral frame structure needs a large amount of the external plates and internal reinforcing members to satisfy the structural strength. By changing the existing column-type integral frame structure to a truss structure, the present invention can reduce resistance to the sea current of the lower structure to minimize the external force, and can prevent vortex-induced vibration by reducing a motion of rotating on a z-axis among 6 degrees-of-freedom motions of the lower structure. Also, the present invention can reduce the amount of the steel materials for the reinforcement of the lower structure; thereby reducing entire displacement so that the volume of a fixed ballast tank can be reduced. As a result, the lower structure according to the present invention can have excellent motion performance and structural stability than the existing lower structure, and can increase cost efficiency by reducing the amount of the structural steel materials forming the lower structure.