Offshore wind is an attractive means for achieving the nation's clean energy policies due to high electricity demand at coastal states and its proximity to population centers. A major portion of potentially exploitable offshore wind resources is located in deep water, leading to a need for cost-effective floating offshore wind turbine (FOWT) systems. Despite the development of floating technologies, the high capital cost of the support system still remains a primary obstacle. This study presents a novel, efficient multiline ring anchor (MRA) system having the potential to provide significant cost savings and evaluate its horizontal load capacity using three-dimensional finite element (3-D FE) analyses. Preliminary two-dimensional studies show that width, number of wing plates, and load angles alter the collapse mechanism and lateral bearing factors of the MRA in soft clay. This study expands on those studies using 3-D FE analyses to evaluate the effects of load application depth and aspect ratio on the lateral undrained capacity of the MRA, including consideration of the effects of wing plates. The studies show that adding wing plates to the tubular core of the anchor adds substantially to ultimate load capacity. The wing plates have minimal influence on the rotational and forcemoment interaction characteristics of the anchor.
Charles Aubeny and Junho Lee
Keywords: anchor, multiline, wing plates, floating, mooring, lateral bearing factor, short aspect ratio, offshore wind farm
Publisher: DFI