Application of wavelet analysis to differences in modal rotations for damage identification

Shearography is an effective non-destructive testing method which already found numerous applications in structural damage identification and for various industrial branches. This method, however, consider the detection and localization based on the irregularities found on rotation fields. This paper presents the concept of non-destructive damage identification in structural elements using modal rotation together with advanced signal processing for the enhancement of its sensitivity, thus allowing for overcoming the problem of small damage detectability. The presented approach uses a set modal rotations fields of a beam, initially processed from shearographic phase maps, for undamaged and damage states. The difference in modal rotations, between the two damages states, is initially calculated and afterward is subjected to a wavelet transform. The presented results show the effectiveness of the presented approach in tasks of structural damage identification.