In this paper, the wavelet transform is applied to the time- frequency analysis of the flexural waves in beams for crack detection. Here, a cantilever beam with edge cracks is used for a model to analyze the wave information after it is loaded an impact hammer on its free end. The flexural waves propagating in beams are dispersive and can be measured directly by using electrical-resistance strain gauges during the dynamic process. According to the data about one-crack and two-crack beams, we utilize the Morlet wavelet transform to decompose the flexural waves into each frequency component in time domain. The experimental results illustrate that the crack position can be detected exactly by means of the signal of mid-frequency flexural wave extracted by wavelet transform. The method is also suitable for determining the existence and location of multi-crack in a beam.

Date Published: 29 May 2002
PDF: 4 pages
Proc. SPIE 4537, Third International Conference on Experimental Mechanics, (29 May 2002); doi: 10.1117/12.468829

Published in SPIE Proceedings Vol. 4537:
Third International Conference on Experimental Mechanics
Xiaoping Wu; Yuwen Qin; Jing Fang; Jingtang Ke, Editor(s)