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 6.25Formula: see textMW 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.
Wang et al. (Wed,) studied this question.