Detection of a radial crack in annular structures using guided circumferential waves and continuous wavelet transform

A quantitative identification method for radial cracks based on the guided circumferential wave (GCW) and continuous wavelet transform (CWT) is proposed in this research. The Gabor wavelet is used to extract a proper frequency component of a beneficial wave mode for evaluation of crack from the highly dispersive and multi-mode waves. The GCW components with different frequencies are considered and their effectiveness in crack detection is compared. Both numerical simulations and experiments are conducted on a Plexiglas annulus with a radial crack. Results show that the crack location is determined with high precision using the CWT to extract an appropriate GCW component, and the 1st mode corresponding to the Rayleigh surface wave is more reliable in crack detection than other modes under investigation. Furthermore, a GCW component with too low a frequency involves overlapping of waves and insensitivity to damages while that with too high a frequency has small amplitude and is complicated with many wave modes. Thus a wave component which simultaneously has adequate amplitude and good sensitivity is proven to be effective for examination of crack.

► A quantitative identification method for radial cracks is proposed.
► The Gabor wavelet is used to analyze the dispersive guided circumferential waves.
► An appropriate frequency component is extracted to locate the crack.
► Results show the crack location is determined with high precision.
► The beneficial wave mode for radial crack detection is suggested.