Abstract
Many studies about the characteristics of fracture strength and fracture toughness for ceramics are conducted based on linear facture mechanics. But, the evaluation method of reliability of ceramics is not well estabilished.
Meanwhile, numerous microcracks and phase transformation are formed ahead of the crack tip of ceramics. That is called “process zone”. This process zone toughen a material by microcrack or stress shielding mechanism.
In this study, authors examined the relation of equivalent crack length and fracture strength based on proposed failure criterion model. And analized the characteristics of reliability of the fracture stress and fracture toughness by using Weibull distribution. Lastly, authors propose a new failure assessment diagram based on both probability concept and process zone size failure criterion.
