Detection of Single and Multiple Cracks in Circular Cylindrical Shells Using Modal Analysis and Wavelet Transform

In this paper, a method is studied for detecting single and multiple cracks in the thin and thick-walled Circular cylindrical shell based on the modal analysis and wavelet transform without using baseline modal data. In this research, the studied crack is the type of circumference and all over and it is also modeled in the form of hairline and without width by the ABAQUS software. The mode shapes of two thin and thick-walled cylindrical shells are obtained with free-free and simple-simple support conditions and with different cracks ratio. The cracked sample response is moved to static wavelet transform toolbox in the MATLAB software. Then, the noise signal is obtained by assuming crack as noise and removing noise at the first decomposition level of the input signal and. Finally, after reviewing 3240 various modes, the best wavelets are introduced to accurate detection of the cracks up to 2% crack ratio and without displaying the support effects.