Modal-Based Free and Forced Vibration Analysis and Optimization of a Pre-Twisted Composite Wind Turbine Blade

The increasing global demand for clean energy has established wind power as a leading solution for sustainable electricity generation. The efficiency and reliability of wind turbines are strongly influenced by blade design, which governs both aerodynamic performance and structural integrity. In this study, a wind turbine blade based on the National Advisory Committee for Aeronautics (NACA) 4412 airfoil was developed for composite manufacturing, with variations in laminate layers (4, 8, 12, and 16) to optimize stiffness, strength, and weight. To reduce prototyping costs and development time, the structural response under operational loads was simulated using ANSYS Workbench 2025 R1. The Taguchi method was employed to minimize the number of experimental trials, considering three factors at four levels each. A multi-objective optimization was then performed to minimize tip deformation and maximum stress while ensuring a safe failure index. The results indicated that force distance was the most influential factor, followed by laminate configuration, while force magnitude had a comparatively smaller effect within the tested range. The configuration with a force of 15 N, a force distance of 60 cm, and 12 laminate layers achieved a composite desirability of 0.9413, leading to a significant reduction in deformation and stress while maintaining structural safety. These findings validate the effectiveness of the proposed design and optimization framework and provide practical guidelines for the development of high-performance composite wind turbine blades.