Strength Analysis of Brittle Materials
Final rept. Apr 1973-Oct 1977,
BATTELLE COLUMBUS DIV OH
Pagination or Media Count:
Fracture stresses in specimens of four commercial polycrystalline ceramics differing in each linear dimension by a factor of four or five were measured at room temperature under controlled conditions. Data obtained were analyzed with the aid of fractographic examinations for applicability of Weibull statistics. A central problem in attempting to use ceramic materials in demanding structural applications is uncertainty about the stresses to which they can be safely subjected. A ceramic rarely, if ever, exhibits a characteristic failure stress. This stress depends on the nature and distribution of microscopic flaws that intensify stress locally, and fracture initiates at a single worst flaw when Griffiths criterion for crack instability is met. Within the basic framework, theories are available for treating effects of time, size, and stress distribution on failure stress. This paper reviews these theories, and discusses their use in specifying limiting stresses in designing structural members.
- Ceramics, Refractories and Glass