Crack detection in a shaft by combination of wavelet-based elements and genetic algorithm

A new crack detection method is proposed for detecting crack location and depth in a shaft. Rotating Rayleigh-Euler and Rayleigh-Timoshenko beam elements of B-spline wavelet on the interval (BSWI) are constructed to discretize slender shaft and stiffness disc, respectively. According to linear fracture mechanics theory, the localized additional flexibility in crack vicinity can be represented by a lumped parameter element. The cracked shaft is modeled by wavelet-based elements to gain precise frequencies. The first three measured frequencies are used in crack detection process and the normalized crack location and depth are detected by means of genetic algorithm. To investigate the robustness and accuracy of the proposed method, some numerical examples and experimental cases of cracked shaft are conducted. It is found that the method is capable of detecting crack in a shaft. (C) 2008 Elsevier Ltd. All rights reserved.