Upcycling of Decommissioned Wind Turbine Blades: An Investigation of Stress Distributions in Glass Fiber-Reinforced Polymers Beams

Wind turbines are among the most widely adopted renewable energy systems, yet the end-of-life management of wind turbine blades remains a major challenge. The turbine blades are primarily made of glass fiber-reinforced polymers (GFRP), which are difficult to recycle without degrading their inherent structural integrity. Instead of shredding or downcycling, this study explores a reuse strategy that preserves intact laminate from decommissioned blades and repurposes them into structural beams via glue-laminated fiber-reinforced polymers (GL-FRP) assemblies. This concept was implemented using commercial GFRP for blade-derived laminates, focusing on the structural feasibility rather than material sourcing. Adhesive joints were designed as the key enabling mechanism for structural reuse and characterized under tensile loading. Building on this, the flexural performance of GL-FRP beams was investigated in horizontal and vertical configurations, yielding an ultimate load-bearing capacity of 8 kN and 20 kN, respectively. Furthermore, stress distributions obtained from experiments, finite element (FE) simulations, and analytical frameworks were evaluated and compared. The results highlight the governing role of interlaminar stress in determining structural performance and failure of the horizontal beam. The findings provide a foundational understanding of repurposing decommissioned wind turbine blades as structural elements, offering a novel strategy for material upcycling in wind energy sector and contributing to the development of circular construction solutions.