Damage detection of circular hollow cylinder using modal strain energy and scanning damage index methods

The detection of surface crack in a circular hollow cylinder is presented in this paper. Experimental modal analysis is conducted on the cylinder to obtain the modal displacements used to compute the modal strain energy. For all measured mode shapes, a damage index is defined by using the ratio of modal strain energies of cylinder before and after damage. A scanning damage index is developed by moving damage indices obtained from the local area throughout the structure. The summation of damage indices in overlap areas may intensify the signals of damage in the cylinder.