Semnan University Press Mechanics of Advanced Composite Structures 2423-4826 Articles in Press 2026 04 22 Structural Evaluation of a Horizontal Axis Wind Turbine Composite Blade Using a Monitored Testing Bench 10580 10.22075/macs.2026.38742.1910 EN Omar Rajad LRPSI, Polydisciplinary Faculty, Sultan Moulay Slimane University, Beni Mellal, Morocco EMISys Research Team, E3S Research Center, Mohammadia School of Engineers, Mohammed V University in Rabat, Morocco Multidisciplinary Laboratory of Exact and Applied Sciences, Superior School of Technology, Fkih Ben Saleh, Morocco Youssef Idihya EMISys Research Team, E3S Research Center, Mohammadia School of Engineers, Mohammed V University in Rabat, Morocco Hamid Mounir EMISys Research Team, E3S Research Center, Mohammadia School of Engineers, Mohammed V University in Rabat, Morocco Mohamed Rich LRPSI, Polydisciplinary Faculty, Sultan Moulay Slimane University, Beni Mellal, Morocco Ikram Outla Alkhalil Center, Private laboratory of Engineering Energy, Beni Mellal, Morocco Journal Article 2025 08 20 This study presents a comprehensive evaluation of the mechanical performance of a segmented 3D-printed composite prototype blade. To assess its stiffness characteristics, the blade was subjected to systematically applied load levels in the flapwise direction. The experimental campaign enabled detailed characterization of the blade's stiffness and the initiation and evolution of damage as a function of applied loading and the number of fatigue cycles. A statistical analysis was performed to quantify the uncertainty and repeatability of the measured results. <br /><br /><br /><br />A specialized test bench was designed and constructed to accommodate fatigue testing of blades measuring 712~mm in length. The blade was subjected to controlled cyclic loading while its mechanical response was continuously monitored using a high-resolution imaging system. The collected data revealed a significant increase in total deformation energy of 77.5\%, particularly near the root (point~1), and a corresponding decrease in stiffness of 77\% after cyclic loading in the flapwise direction. <br /><br /><br /><br />These results provide critical insights into the blade's structural health and dynamic response during service and have informed improvements in the manufacturing process to ensure that the final products meet stringent reliability and safety standards under severe operating conditions. Uncertainty and repeatability were further evaluated by testing two blades with identical geometry and material properties, demonstrating that the derived results were accurate within an error margin not exceeding 10%. https://macs.semnan.ac.ir/article_10580_e9f399263d7ccc7a35b194ee62d716f8.pdf