Delamination detection in composite laminates using auto-regressive models of vibration signals

In this paper, the detection of delaminations in Carbon-Fiber-Reinforced-Piastic (CFRP) laminate plates induced by Low-Velocity lmpacts (LVI) is investigated by means of Auto-Regressive (AR) models obtained from the time histories of the composite specimens. A couple of piezoelectric patches for actuation and sensing purposes are employed. The normalized data recorded of the pristine plate configuration are analyzed in order to obtain thc most suitable AR model through proper dedicated technique. Linear Discriminant Analysis (LDA) is then applied on the AR models parameters to enhance the performance of the proposed delamination identification routine. Results show the effectiveness of the developed procedure when a reduced number of sensors is used.