Abstract
The strength evaluation method for engineering ceramics is described. The method is based on the Weibull statistics and the weakest-link theory. In the method, ceramics is treated as a brittle body containing many defects of various sizes. When any one of such defects satisfies the fracture criterion, the fracture of the whole body occurs. The size distribution of the defects is such that the strength distribution of the body obeys the 2-parameter Weibull distribution. The time-dependent strength is represented as a result of the SCG (Slow Crack Growth). The concept of the effective loading stress is shown to be very useful to evaluate the time-dependent strength of ceramics.
Many aspects of the method which appear in the application to the practical use are described such as fast fracture, static fatigue, dynamic fatigue, cyclic fatigue, effective volume, 3-parameter Weibull distribution, minimum strength, determination of Weibull modulus, fatigue limit, unified estimation method of strength, environmental effects and nonlinear fracture mechanics.
A brief explanation is also made here about an example of strength design guides for ceramic components which is based on the evaluation method described above.
