Mixed-mode fracture of ceramics in asymmetric four-point bending: Effect of crack-face grain interlocking/bridging
- Toyohashi Univ. of Technology (Japan). Dept. of Materials Science
The mixed-mode fracture of a large-grain-size alumina ceramic and a soda-lime glass is investigated. These ceramics are tested using straight-through precracked or notched specimens. The straight-through precrack is introduced by the single-edge-precracked beam method. Precracked or notched specimens are subjected to combined mode I/II or pure mode II fracture, under asymmetric four-point bending, and pure mode I fracture, under symmetric four-point bending. A pure mode II fracture is never achieved in the precracked polycrystalline alumina by the crack-face friction inevitably induced by grain interlocking/bridging. The crack-face friction in sliding mode reduces the local mode II stress intensity factor in the crack-tip region and produces a sizable amount of mode I deformation. Accounting for the contribution of the crack-face friction to the crack-tip local stress intensity factors, K{sub I} and K{sub II}, in mixed-mode fracture tests, the experimental results of the K{sub I}/K{sub Ic} versus K{sub II}/K{sub Ic} envelope and the initial angle of noncoplanar crack extension are in good agreement with the theoretical predictions of the maximum hoop-stress theory.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 413323
- Journal Information:
- Journal of the American Ceramic Society, Vol. 79, Issue 10; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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