Zero-Group Velocity (ZGV) Lamb waves are studied in a structure composed oftwo plates bonded by an adhesive layer. The dispersion curves are calculatedfor a Duralumin/epoxy/Duralumin sample, where the adhesion is modeled by anormal and a tangential spring at both interfaces. Several ZGV modes areidentified and their frequency dependence on interfacial stiffnesses and on thebonding layer thickness are numerically studied. Then, experiments achievedwith laser ultrasonic techniques are presented. Local resonances are measuredusing superimposed source and probe. Knowing the thicknesses and elasticconstants of the Duralumin and epoxy layers, the comparison between theoreticaland experimental ZGV resonances leads to an evaluation of the interfacialstiffnesses. A good agreement with theoretical dispersion curves confirms theidentification of the resonances and the parameter estimations. Thisnon-contact technique is promising for the local evaluation of bondedstructures.
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