Paper number 306

NON DESTRUCTIVE INSPECTION OF WEAK BONDS IN ADHESIVELY BONDED JOINTS

Dong Fei, Krishnakumar Shankar

School of Aerospace and Mechanical Engineering, University College
University of New South Wales, Australian Defence Force Academy
Northcott Drive, Canberra, ACT 2600, Australia

Summary

For a convincing adhesively bonded joint or adhesively bonded reinforcement of a plate, non-destructive inspection (NDI) is an important procedure to assure the strength and the durability of the joint or the repair. A number of NDI methods are available for detection of lack of quality due to disbonds, voids, etc. However, the detection of weak bonds due to poor quality of the interface between the adhesive and the adherend is still not well established. This paper investigates the possibility of using sensitive optical interferometric measurement to detect adhesion weakness in bonded joints. Finite element analysis shows that the peel deformation in an unsymmetrically weak joint could be a feature for detection of weakness while in-plane deformation of weakly bonded joints is indistinguishable from that of well-bonded joints. Results using an overlay double exposure holographic interferometric system show promise as a potential NDI method for monitoring adhesion weakness.

Keywords

non-destructive inspection, adhesively bonded joints, weak bonds, adhesive weakness, bond durability, bond integrity, bonded lap joints, peel deformations.