Quantitative assessment of damage in a structural beam based on wave propagation by impact excitation

A damage identification system involving a surface-attached piezoelectric transducer was developed in this study in correlation with an elastic wave propagation model. A signal processing and identification algorithm in the time-frequency domain based on the wavelet transform technique was proposed to suppress the diverse broadband interferences and effectively extract useful diagnostic information from the acquired raw impact responses, facilitating a prompt yet accurate structural health assessment. The developed system was then validated by applying it to a defective metal beam bearing a transverse crack with an increasing depth that simulates the crack growth. It is shown that the monitoring for the variable damage severity in the one-dimensional structure can be fulfilled quantitatively and exactly using this technique.