# Wideband Vibro-Acoustic Modulation for Crack Detection in Wind Turbine Blades
## 4 Conclusions  
The present research introduces a new approach to crack and damage detection in WT blades based of the modulation of the naturally excited blade vibrations by the altered load during blade rotation. The developed model allowed the estimation of the non-linear signal SNR based on the known data of the resonance frequency and the damping variations occurring in the presence of cracks. As far as we know, this study was the first work that experimentally and theoretically applied a wideband signal in VAM and analyzed the application of natural vibrations in the VAM SHM of WT blades. The suggested VAM method for crack and damage detection in WT blades can be implemented via the currently used SHM systems. This implementation does not require additional hardware and can use algorithms for the extraction of the non-linear effects that are described in this paper. Future works will be conducted using WT blades employing wideband blade modulation on a small-scale model, with the blade being 2 m in length. Conceptualization, A.A. and A.S.; experimental methodology, A.A.; signal processing software, A.A. and A.S.; validation, A.S. and A.A.; formal analysis, A.A.; investigation, A.S.; writing--original draft preparation, A.A.; writing--review and editing, A.A. and A.S.; visualization, A.A.; supervision, A.S. All authors have read and agreed to the published version of the manuscript. Figure 17: Steel fatigue life assessment using the DEMON technique for a 10-hertz component versus the normalized number of cycles load [58]. * [PERSON] et al. (2014) [PERSON]; [PERSON]; [PERSON] Structural Health Monitoring of Wind Turbine Blades. In _Wind Turbine Control and Monitoring_; [PERSON], [PERSON], [PERSON], Eds. ; Advances in Industrial Control; Springer International Publishing: Cham, Switzerland, 2014; pp. 231-265; ISBN 978-3-319-08413-8. * [PERSON] and [PERSON] (2022) [PERSON]; [PERSON] Vibration-Based Damage Detection in a Wind Turbine Blade through Operational Modal Analysis under Wind Excitation. _Mater. Today Proc._**2022**, _56_, 291-297. [CrossRef]
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