A Hybrid Procedure for Structural Damage Identification in Beam-Like Structures Using Wavelet Analysis

Abstract

There are significant changes in the dynamic responses of damaged structures in which the damage depth becomes influential. This fact enables the recognition of damages in structures from their dynamic response data. This paper aims to identify damage locations as well as quantification of damage extent utilizing a vibration-based method. In this work, a signal-based damage identification procedure using the information entropy of wavelet packet energy is employed to evaluate beam-like structures. Damage indices called singular wavelet packet entropy and relative wavelet packet entropy are proposed to identify the location and to quantify the structural damage. The method involves two steps: firstly, the singular value of wavelet packet entropy, which reveals the abnormality distribution of the energy in signal time-frequency domain and secondly, relative wavelet packet entropy that is an acceptable damage feature to examine damage location and quantitative evaluation of the extent of damages through the vibration signals. The effects of wavelet type and decomposition level on the detection of damage location are examined. Numerical and experimental results from four test beams are used to verify the viability of this method. Results show that the damage indices method has great potential in identification of location and depth of cut in a steel beam. The procedure can be used for health monitoring of other complex structures.