A Comprehensive Study on the Selection of Mother Wavelets and Mode Shapes for Multiple Damage Identification

The aim of this paper is to find the proper families and mother wavelets for a successful localization of multiple damages in beams. The post-processing of differences in modal rotations, experimentally measured with shearography, and differences in modal curvatures of aluminium beams are carried out with 14 wavelet families and 84 mother wavelets. The damage identifications show that the best families of wavelets for the post-processing of modal data are the Shannon, frequency B-spline, and complex Morlet families. In order to select the modes that are more sensitive to damage, a novel parameter for the evaluation of the most changed mode is proposed. The boundary effect, which is often found in wavelet-based damage identifications, is also addressed in this paper. The results show that the post-processing of differences in modal curvatures yields better damage identifications than the post-processing of differences in modal rotations.