COMPOSITE BONDED JOINTS Interlocking Fiber Configuration Effect on Mode-I Disbond Arresting in Composite Bonded Joints

Adhesively bonded joints have various advantages when compared with bolted joints. However, bonded joints are not reliable enough to be applied to primary aircraft structures. Therefore, airframes are assembled by using hundreds of thousands of bolts despite the significant potential of bonded joints. New disbond arrest features that can limit disbond to an uncritical size are one of the key elements to achieve certified bonded aircraft structures. Although various design features have been proposed already, they are not satisfactory in respect of their stiffness and initial failure strength. In this paper, an interlocking fiber feature is introduced in bonded joints, and its configuration effect on mode-I disbond arresting is evaluated. Three types of arrester configurations with various fiber volumes are compared in terms of their mechanical performance and failure pattern in double cantilever beam tests. Finite element analysis is also performed to clarify the crack-arresting mechanism of each configuration.