Damage detection and characterisation by processing of laser vibrometer measurement results: application on composite materials

摘要

In recent years damage detection techniques based on vibration data have been largely investigated with promising results for many applications.In particular, several attempts have been done to determine which kind of data must be extracted for damage monitoring. In this work Scanning Laser Doppler Vibrometry (SLDV) has been used to detect, localize and characterize delaminations in compositematerials.In order to improve understanding of the analysed phenomena and to design efficient post-processing algorithms for experimental SLDV data, a theoretical lumped model has been developed by the authors. The model describes the dynamic behaviour of thestructure in the delamination zone.Following the model results, an experimental investigation by SLDV has been performed on panels with known detachments. Results have been compared with those achieved by thermal tomography, which at present is one of the most used techniques formonitoring the state of composite materials.The presented methodology has proved to be efficient also to determine the delamination deepness.