PSI - Issue 68

Hugo Mesquita Vasconcelos et al. / Procedia Structural Integrity 68 (2025) 795–801 Hugo Mesquita Vasconcelos et al. / Structural Integrity Procedia 00 (2025) 000–000

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Fig. 7. Squared temperature difference distribution and visible image with specific zones highlighted

Additionally, the analysis shows smaller temperature differences in the upper part of the blade compared to the bottom part. The 29-meter blade, with its 1.5-meter extension, exhibits a distinct pattern: the cooler, bluer middle section (section b of Fig. 7) possibly corresponds to the interface between the original blade tip and the extension, typically bonded with epoxy. This area shows no significant voids, as evidenced by the lack of temperature variation during the heating process. The greater temperature differences observed between the upper (a) and lower sections (c) are likely due to the longer operational time of the older, original bottom section In the visible light image (right image of Fig.7), dark areas can be seen on the left side of the blade (red rectangle), indicating potential surface damage. However, it is not possible to assess the internal extent of the defect through this image alone. The infrared analysis, on the other hand, provides additional information, suggesting that the visible dark areas may correspond to internal damage extending into the blade's extension. This discrepancy between visible light and thermal images highlights the capability of thermography to detect subsurface defects that are not visible to the naked eye. It is crucial to emphasize that this analysis is preliminary and intended to provide an initial assessment of the structural integrity. Further, more detailed analyses are necessary to confirm these findings and fully characterize the blade's structural integrity. 4. Conclusion This study demonstrated the potential of using UAV-based thermographic analysis for non-destructive evaluation of wind turbine blade integrity. The methodology, validated through field trials, effectively identified potential subsurface defects by capturing thermal images under varying temperature conditions. The field trials presented several challenges, including limitations in the resolution of the thermal camera when capturing full-length blade images. This made it necessary to focus on smaller segments to achieve higher resolution and better defect detection. Overall, this study contributes to the growing body of research on non-intrusive maintenance techniques for wind turbines, offering a viable alternative for blade inspections, particularly in remote or offshore locations. While the proposed method has shown promise, it is not without limitations. Future work should focus on enhancing the