ACCURATE CHARACTERIZATION OF CRACKS IN BEAM-LIKE STRUCTURES USING SQUARE CURVATURE MODE SHAPE: WITHOUT BASE LINE DATA

Abstract

In this paper, a new modal parameters-based damage detection method has been proposed. This method is based on accurately composition of 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 ones. Curvature mode shape method is presented to demonstrate 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 another experimental based results. From the results, it can be seen that damage scenarios of the two beams are quite different the chosen method is precisely identifying 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. Further, an influence of mode order on damage identification also investigated in the present analysis.

Keywords

• Beam-like structure
• mode profiles
• Crack detection
• Mode shape curvature
• Experimental Modal Analysis