Effect of shallow-angled skins on the structural performance of the large-scale wind turbine blade

Flutter performance of large-scale wind turbine blade with shallow-angled skins

“…2, was developed by downscaling the geometry and composite layup of the reference 13.2MW wind turbine blade of length 100m, titled as SNL 100-00, developed by Sandia National Laboratories, USA [13]. The composite layup, geometry (i.e.…”

“…Table 2 lists the back-calculated UD ply longitudinal, transverse and shear stiffness properties, denoted respectively by E x , E y and E xy, respectively. Further information regarding the development of the ply-level layup of the downscaled 5MW blade can be found in [13]. …”

“…For the asymmetric skin configuration, the shallowangled skin was applied to only the PS; the SS skin was conventionally 45°-angled. shallow-angled asymmetric skins [13].…”

“…The increased stiffness and strength were then lowered by thinning the spar caps, resulting in a 8% and 13% decrease in the blade overall mass (see Table 3) for both skin configurations at 35 o and 25 o off-axis fiber angles, while the all design requirements [13]. …”

“…Two shallow-angled symmetric and asymmetric skin configurations (as detailed in Section 2.2) with 35 o and 25 o off-axis fiber angles were previously proposed in [13], based on the observation that considering the slenderness of the large-scale blade the conventional 45° off-axis fiber angle of the blade skins is not optimal. The shallow-angled skins were evaluated by their application to a utility-scale variable-speed and collective-pitch controlled 5MW wind turbine blades, in terms of tip deflection, modal frequencies, buckling load factor and strength failure index.…”