A transverse-wave ultrasonic oblique-incidence technique for interfacial weakness detection in adhesive bonds

Abstract

The possibility of using an ultrasonic oblique-incidence technique for improved sensitivity in interfacial weakness detection in adhesive bonds was considered. The analysis of the sensitivity of transverse waves to interface imperfections on an interface between two semi-infinite half-spaces with bond rigidities of various finite values was carried out. Excellent sensitivity is obtained for discriminating bond weaknesses from a perfect or welded situation to a poor or smooth situation compared to longitudinal wave impingement and reflection. The optimal angle of incidence for the inspection of an aluminum-to-aluminum adhesively bonded structure in an immersion technique is presented. Additionally, a signal feature in frequency domain for adhesive and cohesive weakness distinction is proposed.