Bond strength measurement by ultrasonic guided waves

A quasi-static model is proposed for ultrasonic guided waves interaction with imperfect interfaces. Incomplete bonding and the effect of this condition on the velocity is comprehensively discussed. The theoretical model, serves as reference for extracting ultrasonic wave parameters from experimental data. These parameters are correlated to adhesion strength. This work presents the results of a series of experiments with bonds of varying quality and thickness. Ultrasonic surface waves have been generated by a piezoelectric transducer and the detection was performed using an optical interferometer. The optical sensing of the ultrasonic surface waves is used to provide information about the ultrasonic guided waves which propagates along the boundaries between solids. Specifically, the normal component of the ultrasonic wave has been measured for providing information about the bond strength. The challenge of discriminating imperfect bonds was achieved. (C) 1997 Elsevier Science B.V.