Damage Detection of Circular Cylindrical Shells by Ritz Method and Wavelet Analysis

This paper presents a new technique based on the Ritz method for the damage detection of circular cylindrical shell structures. Sander's thin shell theory together with the Ritz method is used to analyse the dynamic behaviour of circular cylindrical shells. The crack damage on the shell surface is modelled by a rotational line spring along the circumference of the shell. Different damage scenarios are investigated by changing the crack locations and rotational spring stiffness. Modal parameters of shells with different damage patterns are obtained and compared. Wavelet analysis is carried out to detect the discontinuities in the mode shape where the damage is presented. It is found from the numerical results that the natural frequencies of the shell are insensitive to the crack damage. The wavelet analysis is effective to detect the damage in the circular cylindrical shell.