Effect of Adhesive Ductility on Cyclic Debond Mechanism in Composite-to-Composite Bonded Joints |
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| Authors: | S Mall K T Yun |
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| Affiliation: | 1. Department of Aeronautics and Astronautics , Air Force lnsitute of Technology , Wright-Patterson Air Force Base, OH , 45433-6583 , U.S.A.;2. Department of Aerospace Engineering and Engineering Mechanics , University of Texas , Austin , TX , 78712 , U.S.A. |
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| Abstract: | An investigation of an adhesively bonded composite joint with a brittle adhesive was conducted to characterize both the static and fatigue debond growth mechanism under mode I and mixed mode I-II loadings. The bonded system consisted of graphite/epoxy adherends bonded with FM-400 adhesive. Two specimen types were tested: (1) a double-cantilever-beam specimen for mode I loading and (2) a cracked-lap-shear specimen for mixed mode I-II loading. In all specimens tested, failure occurred in the form of debond growth either in a cohesive or adhesive manner. The total strain-energy-release rate is not the criterion for cohesive debond growth under static and fatigue loading in the birttle adhesive as observed in previous studies with the ductile adhesives. Furthermore, the relative fatigue resistance and threshold value of cyclic debond growth in terms of its static fracture strength is higher in the brittle adhesive than its counterpart in the ductile adhesive. |
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| Keywords: | Adhesive bonding Composite materials Debond propagation Strainenergy-release rates Fracture mechanics fatigue |
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