Abstract:

An ultrasonic guided wave method suitable for evaluating the interfacial bonding property of the ultra thin two layer composite is presented. The “ultra thin” here means that the thickness of the layer is only a fraction of the ultrasound wavelength so that the echoes from the front and back surfaces cannot be separated in the time domain. The interfacial bonding condition of the ultra thin two layer composites is estimated by using the dispersion properties of the ultrasonic guided waves propagating through it. The reasons for evaluation error of the parameters and the sensitivity of the method are analyzed. In experimental study the technique is employed to characterize the interface properties of the ultra thin aluminum/brass composite with thickness down to 10 percent of the ultrasonic wavelength with a pair of broadband 2MHz longitudinal wave transducers. It is observed that the agreement between the nominal value and the estimation is excellent.

Key words: composite structure, interface property, ultrasonic QNDE, guided wave, dispersion property