[4E2] Detection of delamination defects in CFRP of wind turbine blades based on laser-generated Lamb waves
J He
Hangzhou Dianzi University, China
Carbon fibre-reinforced polymer (CFRP) has been widely used in wind turbine blades due to its excellent mechanical and thermal properties. Delamination is the predominant failure mode in CFRP, which can significantly reduce its strength and potentially lead to catastrophic failure. While laser-generated Lamb waves are suitable for detecting delamination in CFRP with the advantages of long propagation distance and high detection sensitivity, the low signal-to-noise ratio (SNR) and near-field effect have limited the detection accuracy. This research proposes a quantitative detection method for delamination in CFRP based on Lamb wave signal fusion of dual detection points. First, the effects of laser parameters and material anisotropy on the propagation characteristics of laser-generated Lamb waves in CFRP are analysed through finite element simulations. Second, considering the low SNR and multi-mode aliasing characteristics of Lamb waves in CFRP, a wavenumber filter that matches the directivity pattern of the wavefield is constructed to isolate the delamination-sensitive wavenumber components. Third, by performing differential analysis of the signals from two mirror-configured detection points, the near-field effect can be significantly reduced, enabling high-accuracy detection of delamination defects. Finally, the effectiveness of the proposed method is validated through laser ultrasonic detection experiments on CFRP plates. These research results will provide theoretical guidance for the non-destructive testing of delamination in CFRP.
