Reliability evaluation scheme for ceramics based on defect size distribution inversely estimated from standardized tests

Abstract

Ceramic components fracture stochastically, resulting in scatter and size dependence of the strength. Therefore, the strength properties obtained from a standardized test cannot be directly used to determine the design strength of the arbitrary-shaped components under different boundary conditions for brittle ceramics. In this study, we propose a novel strength evaluation scheme where an inversely analyzed defect distribution is used as a common indicator to evaluate the reliability of brittle ceramic components. First, the defect distribution of the target lot is inversely estimated as a common indicator based on experimental results of the bending strengths using the swarm intelligence optimization method. The scatter of the bending strength tested under different boundary conditions is then predicted using the estimated defect distribution. The analyzed defect distribution was found to be consistent with the observed distribution and can be used to predict other experimental results. The versatility and limitations of the scheme were discussed by examining the selection of a standardized strength test for optimization and the impact of model discretization on the inverse estimation of defect distribution. The results suggest that the proposed scheme can be applied to evaluate the strength scatter of components with arbitrary shapes and under arbitrary boundary conditions.