Viscoelasticity of ceramics at high temperatures
- 41 Downloads
The dependence of the fracture toughness, KIC, on the loading rate has been calculated. On the basis of linear elastic fracture mechanics (LEFM) a strong dependence of the fracture toughness on the loading rate is obtained if subcritical crack growth is taken into account. If the subcritical crack growth parameters n and B are sufficiently small, which correspond to a high velocity of crack extension, the fracture toughness should decrease at lower loading rates. This behaviour is similar to the well-known decrease of bending strength. The experimental results for alumina containing glassy phase as a model material, however, show a maximum in a certain regime of loading rates. A model is established, which combines LEFM and the viscoelasticity, and leads to a maximum of KIC at a certain loading rate dependent on the viscosity of the glassy phase.
KeywordsPolymer Alumina Viscosity Fracture Toughness Fracture Mechanic
Unable to display preview. Download preview PDF.
- 3.G. Popp, PhD thesis, University of Stuttgart, FRG (1982).Google Scholar
- 5.European prestandard ENV 820-1.Google Scholar
- 6.DIN-standardization proposal 51110, parts 2 and 3.Google Scholar
- 7.Y. Murakami, “Stress intensity factors handbook”, Vol. I (Pergamon Press, Oxford 1987).Google Scholar