Research on the Adhesive Strength of Different Bonding Structures for Modular Wind Turbine Blades

To address the manufacturing and transportation challenges of large wind turbine blades, adhesive joints in modular blades have become a research focus. This study investigates six typical adhesive joint configurations for CFRP laminates using quasi-static three-point bending experiments and cohesive-zone finite element simulations. The adhesive interface is modeled with a bilinear traction-separation law using zero-thickness cohesive elements to capture damage initiation and propagation. Among the six designs, the double-slope joint exhibits the best static performance, achieving the highest peak load of 1017.26 N and showing delayed damage evolution. The superiority of the double-slope design is further examined at the blade level via a numerical cantilever model of equal-section modular blade segments under flapwise and edgewise loading. The predicted peak loads reach 9.82 × 10⁷ N (flapwise) and 5.51 × 10⁷ N (edgewise), ranking the double-slope joint highest among the investigated configurations. The findings show that the double-slope joint improves load capacity and resistance to degradation, and reveal failure mechanisms of adhesive joints, providing theoretical support for blade structural design.