FRACTURE BEHAVIOR OF ADHESIVELY BONDED COMPOSITE-TO-METAL LAP JOINTS WITH THICK ADHERENDS

摘要

This paper presents part of the results of a wider research program on the study of bond fracture and resulting stiffness loss in adhesive bonded composite-to-aluminum single lap joints. Test specimens consisting of long lap joints with thick adherends were subjected to incremental loading until complete failure. The effects of epoxy adhesive rigidity and temperature on joint deformation behavior were investigated. In the temperature studies, tests were conducted at room temperature and at -40℃ . In each test, the stiffness reduction due to fracture of the adhesive bond was calculated from load-displacement curves. The results showed that stiffness reduction was higher where delamination joint failures occurred, and that the composite adherend was more prone to delamination when bonded with a flexible epoxy and loaded at -40℃. On the other hand, the joints bonded with a more rigid epoxy failed by adhesive fracture.