Simulation of anomalous behavior of a small flaw in strength of engineering ceramics

✍ Scribed by Hoshide Toshihiko; Inoue Tatsuo

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 575 KB
• Volume: 38
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(91)90008-o

✦ Synopsis

It has been reported that the strength of ceramic materials decreases with decreasing flaw size at the fracture origin. Such anomalous behavior of small flaws in ceramics is discussed, based on experimental observations. A concept of the flaw boundary layer is proposed by the interpretation of acoustic emission data. The layer is assumed to be formed around the dominant flaw during the loading process, and to be more brittle than the surrounding matrix. The distribution of flaws in a ceramic component is two-dimensionally modeled by assuming the independence of the location and the size of the flaws. Taking account of the stress distribution in the component, the maximum of the stress intensity factor of flaw in the component is calculated to determine the flaw dominating the fracture. Based on the model using the concept of the flaw boundary layer, a simulation of the Monte Carlo type was made to explain the anomalous behavior of small flaws. In the relation between the flaw-size and the fracture stress, the simulated result shows the same behavior as the experimental observation.