The invention discloses a
nondestructive testing method for
composite material defects, and relates to the technical field of
nondestructive testing, and the method comprises the following steps: firstly, collecting a scanning waveform of a test piece A, determining a potential defect area based on an echo amplitude and a
time difference, and outputting a sequence containing space coordinates, an original waveform and focusing parameters; an
effective time window is intercepted after preprocessing, sub-bands are generated through
wavelet packet
decomposition, and
total energy is calculated and normalized to obtain an energy vector; secondly, based on a known sample, evaluating the separability of sub-bands by using a
Fisher criterion, sorting the sub-bands, determining an optimal energy dimension through
cross validation, combining sub-band energy features with phase and
time difference features into composite vectors, inputting the composite vectors into a dual-channel lightweight deep network, outputting defect categories and confidence coefficients, and mapping the defect categories and confidence coefficients to a C scanning frame image; and finally,
backtracking the three-dimensional coordinates, calculating the defect volume and the residual wall thickness, and comparing with a material performance
database to output a conclusion. The problem of misjudgment caused by echo waveform similarity is solved, and detection closed-
loop optimization is achieved.