Abstract
Adhesive bonding is light weight, low cost and easy to manufacture, so it is used in various industrial fields. In order to ensure the reliability of adhesive bonding, an appropriate evaluation of adhesive strength is indispensable. However, since experimental evaluation has a large time and economic burden, a simple and practical delamination criterion and evaluation method are required.
The authors proposed a method for evaluation adhesive strength by Intensity of singular stress field (ISSF) and showed that bond strength can be easily evaluated. In the previous study, analysis was performed in consideration of the three-dimensional geometry of the specimen, and it was shown that the ISSF distribution at the interface end was obtained accurately. In this study, the fracture surface of the actual specimen was observed, and the mechanism by which the fracture occurred was considered from the comparison with the analysis result.
The distribution of ISSF is constant at most positions, but once it approaches the fillet, it decreases once and then increases again, returning to almost the same value as the center. It was also found that the position where the ISSF decreases becomes closer to the center as the adhesive layer becomes thicker. As a result of observing the fracture surface, the fracture origin occurred not in the corner but in the straight part of the bonded end face, which is considered to be in good agreement with the analysis result.
