Damage identification method based on continuous wavelet transform and mode shapes for composite laminates with cutouts

Mode shape has been widely applied in damage identification and localization for plate-like structures. However, each mode shape has its specific sensitivity to the damage at certain location, which results in that the damage extent cannot be identified quantitatively. To improve this deficiency, mode shapes or operational deformation shapes (ODSs) with high frequencies are employed for damage identification to make sure similar sensitivity. In order to enhance the accuracy of damage identification, a damage index is proposed based on the 2D continuous wavelet transform (CWT). Numerical simulations demonstrate that the CWT is more sensitive to damage than gapped smoothing method (GSM), and the proposed method can identify damage quantitatively. Furthermore, a composite plate with cutout was experimentally studied. The damage around the cutout were obviously quantitatively detected by the proposed method with ODSs at high frequencies and are in high agreement with that of ultrasound testing.