Finite Element Analysis of Fracture Strength of Ceramics Containing Small Surface Defects

Abstract

Structural ceramics have excellent properties, but when using ceramics as a structural material, the large scatter in fracture strength is an obstacle. It is known that the variation in fracture strength is related to the distribution of defects and pores distributed inside the ceramics. The authors' group has so far proposed a method for predicting the scatter in fracture strength by incorporating the internal defect information of ceramics into the FEM as a distribution function. In this report, we extended this method and examined the effects of artificially added surface defects. In ceramics, it is experimentally known that the relationship between surface defect size and fracture strength deviates from LEFM as the surface defect becomes smaller. Therefore, we added an element that expresses fine surface defects based on linear fracture mechanics to the conventional method. As a result, it was confirmed that the same tendency as in the experiment can be reproduced.