Damage localization by wavelet analysis of uniform load surface

This paper presents a new technique for identifying damages in beam-type structures based on wavelet analysis of uniform load surface (ULS). Having come into focus in the field of damage detection, wavelet analysis revealed itself as a practical and state-of-the-art signal processing method for discerning abnormalities of mode shapes of structures, where the irregularities are considered as the indications of cracks. ULS is beneficial in terms of participating lower mode shapes and better immunity to noise. Continuous wavelet transform (CWT) is employed to analyze the ULS in order to find the damage site. The proposed method does not require any prior knowledge of the structure and combines the synergistic advantages of ULS technique and CWT to provide more accurate results in the face of high signal to noise ratio. A numerical study is conducted and three kinds of wavelets are utilized to evaluate the technique, namely symmetrical 4, Gaussian 4 and bior 6.8. The procedure is also experimentally investigated using a free-free beam structure.