Subcritical crack growth at bimaterial interfaces. Part 3: Shear-enhanced fatigue crack growth resistance at polymer/metal interface
- Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering
Fatigue crack growth along an Al/epoxy interface was examined under different combinations of mode-I and mode-II loadings using the flexural peel technique. Fatigue crack growth rates were obtained as a function of the total strain energy rate for G{sub II}/G{sub I} ratios of 0.3 to 1.4, achieved by varying the relative thickness of the outerlayers for the flexural peel specimen. Fatigue crack growth resistance of the interface was found to increase with increasing G{sub II}/G{sub I} ratio. Such a shear-enhanced crack growth resistance of the interface resulted in a gradual transition of crack growth mechanism from interfacial at the low G{sub II}/G{sub I} ratio to cohesive at the high G{sub II}/G{sub I} ratio. Under predominantly mode-I loading, the damage in the polymer took the form of crazing and cavitation. In contrast, laminar shear occurred under highly shear loading, resulting in a larger amount of plastic dissipation at the crack tip and improved fatigue crack growth resistance.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 203533
- Journal Information:
- Metallurgical Transactions, A, Vol. 27, Issue 1; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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