Fatigue crack growth from indentation flaw in ceramics

✍ Scribed by T. Hoshide; T. Ohara; T. Yamada

• Publisher: Springer Netherlands
• Year: 1988
• Tongue: English
• Weight: 887 KB
• Volume: 37
• Category: Article
• ISSN: 1573-2673
• DOI: 10.1007/bf00017822

✦ Synopsis

The indentation crack has been used as a model of surface flaw in the strength tests of ceramics. In evaluation of such strength properties, some attention should be paid to the residual stress effect due to indentation. In this study, fatigue crack growth behavior from indentation flaws was investigated in sintered silicon nitride and alumina. In both materials, a V-shaped behavior was observed in the relation between the maximum stress intensity factor and the crack growth rate. The indentation crack was analyzed using fracture mechanics procedure to take account of the residual component. On the basis of the analysis, an effective stress intensity factor for crack growth was successfully evaluated. The growth rate was correlated to the effective stress intensity factor, and the relation was found to be approximated by a power law equation. The fatigue crack growth property obtained as above was applied to an estimation of fatigue life of specimens without artificial flaws. The flaw size effect was also discussed based on the result,