Delamination detection in CFRP laminates using a chirp guided wave mixing technique

In this study, we propose a straightforward and easy -to -use method (chirp guided wave mixing, CGWM) for detecting delaminations in CFRP laminates. In this method, two long -duration chirp signals with reversely varying frequency bands are applied to two piezoelectric actuators to generate two broadband guided wave bursts. These waves interact within the specimen, producing sum -frequency harmonics around a target frequency at the defect site. The damage can be directly visualized in the amplitude map at the target frequency without needing complicated post -processing procedures. The feasibility of the CGWM method is demonstrated in experiments and FEM simulations. We compare our proposed method with two other approaches, namely root mean square (RMS) method and higher harmonic (HH) method. The results indicate that the CGWM method exhibits superior sensitivity compared to the RMS method and offers greater simplicity and ease of use than the HH method. Overall, this study presents an innovative approach to frequency manipulation in the field of nonlinear acoustics, providing a promising avenue for delamination detection in composites.