Guided wave resonance identification of interface delamination in bimaterial composites

Laminate composites are widely used in industrial applications due to their high material strength and efficiency. In such materials, impact loads can cause internal delaminations at the bonding interfaces between sublayers, which further growth during operation could lead to structural failure. Guided wave based non-destructive testing allows detecting such hidden delamination, which manifests itself in the wavefield disturbance at the obstacle vicinity. However, their sizing requires sophisticated post -processing of the acquired wave signals. In our previous studies, a method for sizing an internal strip -like crack in a homogeneous elastic plate has been developed and experimentally approved. The method is based on the numerical evaluation of the scattering resonance frequencies depending on the crack size, and their comparison with the experimentally obtained ones. In the present paper, we extend this approach to the case of dissimilar -material laminates. Numerical simulation and laser Doppler vibrometry measurements were carried out for bi-layer samples composed of various combinations of glued steel, aluminium, and glass sublayers with artificial strip -like delamination. The results obtained confirm the possibility of damage width estimation using the values of scattering resonance frequencies extracted from the signals acquired at the sample surface.