Abstract
Slow stable crack growth is a prominent feature of the fracture behaviour of cellulose fibre cements. It is shown that this characteristic can be described by crack growth resistance against crack extension curves based on linear elastic fracture mechanics. Double-cantilever-beam specimens with side grooves are used to obtain such crack resistance curves for a commercial cellulose cement containing approximately 8% mass fraction of bleached fibres. Both dry and wet samples are tested. Compliances measured during slow crack growth by the unloading/reloading technique at successive crack increments are less than those obtained for saw-cut notches with similar crack lengths. Residual displacements due to either mismatch fracture surfaces or a large inelastic process zone at the crack tip are also observed at zero load. A modified elastic potential energy release rate (GR*), and hence its equivalent KR* [= (EGR*)1/2], must be used to include this residual displacement effect in order to yield the true crack growth resistance curves. This is found to be necessary for the wet samples due to their large residual displacements. The crack growth resistances of the wet samples are superior to those of the dry samples: this is explained in terms of the improved ductility and toughness of the wet cellulose fibres.
Original language | English |
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Pages (from-to) | 501-508 |
Number of pages | 8 |
Journal | Journal of Materials Science |
Volume | 19 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 1984 |
Externally published | Yes |
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Science (miscellaneous)
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering
- Polymers and Plastics