Bend-Twist Coupling Design and Evaluation of Spar Cap of Wind Turbine Compliance Blade

Abstract

The bend-twist coupling design method of spar cap of 1.5MW wind turbine blade made by biased hybrid fibers is discussed, and the coupling parameter is established. It is found that flap-twist coupling effect is only related to the laminated materials, not sensitive to the geometry shape. When varying the angle of off-axis carbon fibers from 7.5° to 30° and the volume fraction from 10% to 90%, different bend-twist coupling effect can be obtained. The results show that the optimal angle of spar cap is closer to 18°, and of skins are about 13°. When constraints, such as fibers strain, the in-plane shear stress and Von Mises stress of static index, are added on the blade, the spar cap is optimized with about 45% carbon fiber volume fraction and 18° off-axis angle. Finally, the impact of natural frequencies of dynamic performance on the blade design is proved to be inessential.

Adaptive Bend-Torsional Coupling Wind Turbine Blade Design Imitating the Topology Structure of Natural Plant Leaves

“…Comparatively, the torsion stiffness of the 3 models have little difference. The result achieved in paper (Liu &Zhang, 2010b) accords well with the theory introduced in the context, and it also agrees well with the result in the literature mentioned before. Meanwhile, it validates that the definition of the equivalent parameters in previous section is reasonable.…”