Nondestructive Evaluation of Adhesively Bonded Joints in Graphite/Epoxy Composites Using Acousto-Ultrasonics

This paper is concerned with the use of the acousto-ultrasonic technique to evaluate nondestructively the mechanical performance of composite bonded joints. In this context, acousto-ultrasonic measurements followed by destructive shear tests were performed on single lap joint specimens made from graphite/epoxy adherends joined with FM 300 film adhesive. The results indicate a good correlation between acousto-ultransonic wave propagation characteristics and the shear strength of the bonded joints under different testing conditions. These correlations suggest that an estimation of the joint strength can be made by using acousto-ultrasonics provided that the measurement system is calibrated for variations of the material and geometry of the specimen.