Structural damage detection in an open cross section beam using continuous wavelet transform

Abstract

This paper is concerned with the determination of the damage location and extent of an open cross section beam by continuous wavelet transform on its first mode shape. To extract the mode shape, the finite element method is used, and the damage is modeled by a local decrease in the Young modulus of a beam element. The classic modal analysis techniques based on changes in frequency or mode shape curvature are demonstrated to be insufficient for the damage conditions considered. The technique of wavelet analysis is shown to be more effective than the curvature change method especially in the case of noisy data. Since the beam cross section is not symmetric, the mode shape to be measured is essentially dependent on the location of displacement transducer on the beam width, resulting that the sensitivity of wavelet coefficients to damage will be different. Therefore, in this study, it is also explained where the correct measurement locations must be to obtain the wavelet coefficients more sensitive to damage.