| Autor: |
Thomas W. Coyle, G. Reza Sarrafi‐Nour |
| Rok vydání: |
1999 |
| Předmět: |
|
| Zdroj: |
Journal of the American Ceramic Society. 82:2474-2480 |
| ISSN: |
0002-7820 |
| Popis: |
Chevron-notched specimens are widely used to characterize fracture toughness and the fracture resistance behavior of ceramic materials. Quantitative analysis of R-curves resulting from crack wake bridging obtained by growing a crack in this notch geometry requires an accurate description of the contribution of the bridging tractions to the total stress intensity factor. Three approaches to describe the stress intensity factor due to crack wake tractions in chevron-notched specimens for the case of the commonly employed bend bar geometry are compared to an R-curve calculated using finite element methods for a zone of uniform bridging stress. The results obtained using a recently available fracture mechanics weight function for crack surface tractions in this geometry are shown to be the most accurate. An iterative procedure based on the weight function method which yields the distribution of bridging stresses as a function of crack opening displacement from measured R-curves is described. To illustrate the procedure, experimental R-curve results from an Al2O3-20 vol% SiC platelet composite are analyzed to obtain the bridging tractions as a function of the crack opening displacement. For the specific curve analyzed here, a maximum bridging stress of 26 MPa was found, with a baseline toughness of 4.7 MPa·m1/2. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Plný text