Delamination assessment in structures made of composites based on general signal correlation

This paper considers a vibration-based damage assessment approach which is based on the general idea for signal cross-correlation. Here the method is demonstrated and validated on a composite laminate beam and it is applied for the purposes of delamination assessment in composite structures. The method uses two measures of cross-correlation between two vibration 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 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. In this study the method is applied using the free decay responses of the beam. Two delamination indexes are introduced and they are used for the purposes of delamination detection and localization.