Fundamental mode shape to localize delamination in cantilever composite plates using laser doppler vibrometer

Abstract

The extensive usage of laminated composite plates in various industrial application and their often failure due to delamination encourage the researchers to focus on damage detection of these plates. This study mainly deals with structural damage detection of composite plates. Finite element models of composite plates have been developed and eigen analysis is carried out. Mode shape-based damage indices are proposed to identify delamination and its location. The difference in mode shapes corresponding to delaminated and healthy plates is found to be maximum at the location of damage. Experimental analyses have been performed on healthy as well as delaminated cantilever plates using three-dimensional laser Doppler vibrometer (LDV). The plates were scanned and the dynamic responses were recorded. The mode shapes were then estimated from the scanned response data. The experimental results are found to be in good agreement with that of the numerical illustration in identifying the damage location. The proposed methodology can thus be used in engineering and industrial applications to detect and localize damages in laminated composite plates.