BOND STRENGTH MEASUREMENT BY ULTRASONIC GUIDED-WAVES

A quasi-static model is proposed for ultrasonic guided waves interacti on with imperfect interfaces. Incomplete bonding and the effect of thi s condition on the velocity is comprehensively discussed. The theoreti cal model, serves as reference for extracting ultrasonic wave paramete rs from experimental data. These parameters are correlated to adhesion strength. This work presents the results of a series of experiments w ith bonds of varying quality and thickness. Ultrasonic surface waves h ave 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 ult rasonic guided waves which propagates along the boundaries between sol ids. Specifically, the normal component of the ultrasonic wave has bee n measured for providing information about the bond strength. The chal lenge of discriminating imperfect bonds was achieved. (C) 1997 Elsevie r Science B.V.