Fluid-Structure Interaction Analysis of a Fabric Skin for Fabric-Covered Wind Turbine Blades

Wind turbines are becoming larger to produce more power from the wind in a given area. While the large-size wind turbines are advantageous in terms of generating power, the blades are very heavy and difficult to transport and install. General Electric Co. and the National Renewable Energy Laboratory proposed a new blade design and manufacturing concept that covers the blade with tensioned fabrics. This fabric-covered wind turbine blade is composed of spar-rib structures and covering fabric skins. The present study investigates the aerodynamic effects of fabric skin. A fluid-structure interaction (FSI) analysis was performed about the fabric skin of a large-sized fabric-covered blade. Through static and dynamic FSI analyses, the response of the fabric skin was analyzed according to the wind speeds. The natural frequencies and mode shapes were compared. It was confirmed that the tension of the fabric skin should be increased as much as possible to maintain aerodynamic efficiency, and in addition that the natural frequencies and mode shapes were changed by the wind speeds.