Damage Behavior of Adhesively Bonded Butt and Scarf Joints under Cyclic Loading Conditions
Kiyoshi ISHII, Makoto IMANAKA, Hideaki NAKAYAMA and Hitoshi KODAMA
Abstract:Rubber modified epoxy adhesive has been widely used to structure fields due to its high toughness. The importance of fracture mechanism of the rubber-toughened epoxy is the void formation by rubber particles, where damage zone enclosing the voids propagates in the vicinity of the crack tip. Hence, in considering strength of the rubber modified epoxy, the damage behavior should be taken into account. However, there are few studies about the fatigue behavior of the rubber modified epoxy adhesive discussed from the viewpoint of damage mechanics. In this study, the damage behavior of the adhesively bonded butt and scarf joints under cyclic loading conditions has been studied using a rubber modified epoxy adhesive, where stress triaxiality in the adhesive layer can be varied in a wide range by changing the scarf angle. The strain and crack length of the adhesive layer were monitored by using strain and crack gages pasted on the adhesive layer. A damage parameter is introduced to depict the degree of fatigue damage. Based on these parameters, the effect of stress triaxiality on damage development behavior was discussed. Key Words:Adhesive joint,@ Fatigue, Damage parameter, Modified epoxy adhesive