The effect of free surfaces on the K-crack growth resistance curve for a ligament toughened brittle material
✍ Scribed by E. Smith
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 589 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0013-7944
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✦ Synopsis
Many b&tie materials exhibit a behaviour whereby crack growth is accompanied by the development of a ligament zone behind the crack tip, the restraining stresses due to the crack bridging elements within this zone being responsible for the crack tip stress intensity (#C) increasing during crack growth (R). Analytical results for a range of theoretical modeis hiight the extent to which the K-R curve slope is increased by the presence of free surfaces in two ways: (a) by the proximity of the surface to which the crack propagates, and (b) by the crack being an edge crack rather than a central crack. The particularly high K-R curve slope for an edge-cracked specimen is shown to be due to the ligament zone restraining stresses having an especially marked effect on the crack tip stress intensity, when there is a small remaining ligament between the tip of the edge crack and the opposing free surface.