Delamination assessment in structures made of composites based on signal cross-correlation

This paper considers the application of a vibration-based damage assessment approach based on signal correlation for the purposes of delamination assessment in composite structures. The method uses the cross-correlation between two signals measured in different points on the structure in order to diagnose the delamination. The linear cross-correlation as well as a new measure for nonlinear cross-correlation, the average mutual information are introduced and applied for the purposes of delamination assessment. The delamination assessment is based on the comparison of the measures for the healthy and the damaged state of the structure. Both methods are experimentally validated for the case of a composite beam made of carbon fiber. The two measures are applied with measured free decay acceleration responses. They are used for delamination detection and localization.