Damage detection in beams using wavelet transform on higher vibration modes

Technical difficulties prevented so far wider applications of higher mode shapes in damage detection. Yet these modes carry on a lot of, so much needed, information on damage inflicted to a structure. However, recent scanning laser-based vibration measurement techniques allow one to utilize these higher modes in damage detection effectively. This paper deals with the wavelet-based damage detection technique on a cantilever beam with damage in the form of a single notch of depth 20%, 10% and 5% of the beam height. The purpose of the study is to present the results of experimental and numerical analyses of damage detection based on higher order modes. The first eight modes are considered and the influence of the mode order on the effectiveness of damage detection by the continuous wavelet transform is analysed in detail.