Modal Analysis of Graphene-Reinforced Wind Turbine Blades: With Variable-Width and Airfoil Considerations

To address the core challenge in the wind power industry where pursuing longer blades for enhanced energy yield intensifies resonance risks, this study conducts theoretical and experimental modal analysis on three-phase composite wind turbine blades made of graphene-reinforced glass fiber composites. It fills a key gap in the field: most existing modal models for wind turbine blades ignore airfoil curvature or spanwise variable-width features. Based on the first-order shear deformation theory, combined with the Chebyshev polynomial and the Rayleigh–Ritz method, the study establishes a dual-scale modal analysis framework that integrates airfoil profiles, spanwise variable-width, and graphene gradient distribution to determine the natural frequencies and mode shapes of the blades. The reliability of the proposed model is verified through a three-tier system, including comparisons with published thin-walled structure studies, finite element simulations with grid independence verification, and sweeping frequency excitation experiments. Systematic parametric analysis reveals that increasing the aspect ratio leads to a significant reduction in the blade’s natural frequency and triggers the reconstruction of modal sequences; incorporating graphene as a reinforcement effectively enhances the system’s stiffness to increase natural frequency without altering the basic mode shapes of the blade; the X-pattern distribution demonstrates superior efficacy in enhancing the system’s natural frequency. This improvement is attributed to the strategic concentration of graphene in high-strain regions, which maximizes interfacial stress transfer and optimizes stiffness reinforcement. From an engineering perspective, the findings provide a quantitative design tool for onshore wind turbine blades with a capacity of 6.25[Formula: see text]MW and above, addressing the industry’s core dilemma of balancing blade length and vibration stability, and offering direct technical guidance for the stable design of ultra-long thin-walled wind turbine blades.