Localization of defects in woven-fabric type CFRP plate by time of flight of scattering guided wave

This paper presents a localization method for defects in CFRP plates. A comparison was made for scattering waves from a delamination and from an added block by finite element simulation. The results validate the use of an added mass to simulate the existence of a delamination. Experiments were conducted with magnets stick on the surface of the CFRP plate. The time of flight (ToF) for the scattering wave from magnets were obtained by wavelet transform and Hilbert transform. A probability matrix was constructed to locate the position of magnets. The points that match the ToF of the scattering wave were highlighted. By using four PZT sensors, six probability matrixes can be obtained for the six possible sensor pairs. Combing the results of six probability matrixes, the location of defect can be finally shown in an image of the plate.