Structural Performance of a Glass/Polyester Composite Wind Turbine Blade With Flatback and Thick Airfoils

A 10.3 m wind turbine (WT) blade has been designed to improve structural efficiency of rotor blades. The blade was featured with glass/polyester composites, flatback in the inboard region, thick airfoils in the mid-span region and transversely stepped spar cap thickness. This paper provided an overview of static bending test performed on the blade. Deflections, strains, load-carrying capacity, and failure behavior of the blade were investigated. Finite element (FE) analysis was carried out to complement test and to provide more insights into structural performance of the blade. The blade exhibited linear behavior in spar caps and aft panels at the maximum chord, and it continued to withstand applied loads well beyond the occurrences of local buckling of the shear web and the flatback at the maximum chord. The inboard region showed exceptional load-carrying capacity with failure loads larger than 420% test loads. Through this study, potential structural advantages by applying proposed structural features to large composite blades for multi-megawatt (MW) wind turbines were addressed.