Abstract: The nature frequencies of the cantilever beams with various crack locations and depths are accurately obtained by means of wavelet finite element methods, and then the surface-fitting technique is employed to plot the surfaces of nature frequency. Measured natural frequencies are used in a crack detection process and the crack location and size can be identified through finding the point of intersection of three frequency contour lines. The experimental results verify the validity of the method, which provides a powerful evidence for practical ap-plication.

Key words: Crack, Identification, Nature frequency, Wavelet finite element