Nondestructive testing of adhesively-bonded joints

One approach to testing the suitability of an adhesive joint for a particular application is to build and test to destruction a representative sample of the joint. In this way the best adhesive and surface treatment for a given application can be found. To reduce the costs of this approach, the designer will wish to call on previous experience with adhesives, surface treatments, and joint designs so as to reach a high probability of success before he builds and tests a structural prototype. If structures are expensive, it will be difficult to justify more than a very limited series of prototype tests before production begins. During the production phase, and also in service with critical structures, it is essential to use nondestructive tests to assess the quality and fitness for purpose of the product. The nondestructive test will not measure strength directly but will measure a parameter which can be correlated to strength. It is therefore, essential that a suitable nondestructive test is chosen and that its results are correctly interpreted. In this paper, typical defects found in adhesive joints are described together with their significance. The limits and likely success of current physical nondestructive tests are described, and future trends outlined. © 1997 Elsevier Science Ltd.