A two-step damage identification approach for beam structures based on wavelet transform and genetic algorithm

Abstract

A two-step damage identification approach based on wavelet multi-resolution analysis and genetic algorithm (GA) in beam structures is presented in this paper. The location of the crack is identified in the first step by defining the damage index called relative wavelet packet entropy. Then, the damage severities at the identified locations are assessed in the second step using GA. The wavelet packet component energies for each damage depth used in the first step and the severity evaluation database required for the second step to reveal the relationships between the energies and damage severities are obtained using a multi-resolution wavelet packet transform. The effects of wavelet type and decomposition level on the detection of damage location are examined in beams with various damage scenarios in the presence of different noise levels. To investigate the robustness and accuracy of the proposed method, numerical examples and experimental cases with different damage depths are considered. The results demonstrate that the proposed method performs reasonably well and has great potential in the identification of damage locations and estimation of damage severities.