Abstract :
In this paper, a new modal parameters-based damage detection method has been proposed for accurate characterization of single and multi-surface cracks in beam-like structure. The advantage of this method is undamaged mode profiles from the damaged mode profiles of beam structure. For that, curve fitting (CF) analysis was used to extract the undamaged mode profiles from damaged one. Discrete Wavelet transformation (DWT) method is presented to demonstrate effectiveness of the proposed approach without use of base line data as a reference. To illustration of this method, numerical and experimental modal analysis is performed on two aluminum cantilever beams containing single and double cracks to examine the location and quantification of different damage scenarios. First five modal frequencies and mode profiles are employed to assess the effectiveness of the proposed method. Moreover, to validate the accuracy of the proposed approach in damage identification, established results have been balanced with other experimental based results, which were found in the literature. From the results, it can be seen that damage scenarios of the two beams are quite different the chosen methods precisely identify the location and quantification of the damage in beam structures. It is concluded that composed mode profiles by the proposed approach can be conveniently used as reference data for the damage identification purpose.
Keyword :
Beam-like structure, mode profiles, Mode shape curvature, Experimental Modal Analysis, discrete Wavelet Transform