Influence of carbon/glass hybrid fiber layup structure on the bending-twisting coupling behavior of wind turbine blades

In order to analyze the influence of layer structure of composite material on bending-twisting coupling behavior of wind turbine blade, the carbon/glass biaxial warp knitting fabric with hybrid layer ratio 4∶4 and 2∶6 were selected as reinforcement to fabricate blade. A 2 kW wind turbine blade samples model was established and the strain deform behavior of blade samples was experimental studied by combining classical laminate theory and nodal displacement method. The bending-twisting coupling behavior was also analyzed. The results show that when the carbon/glass hybrid ratio is same and the fiber off-axis angle is 25°, the optimal value of equivalent bending-twisting coupling coefficient of blade samples is 0.186. With same fiber off-axis angle, carbon/glass hybrid ratio 4∶4 blade samples has higher equivalent bending-twisting coupling coefficient than carbon/glass hybrid ratio 2∶6 blade samples. The strain measurement experiment shows that the principal strains decreases gradually along with blade length, and bending-twisting coupling behavior have a good effect on perfecting the principal strain at the blade root.