MICRO-MECHANICS FOR TRIPLE-POINT FLAWS IN CERAMICS

A model for the triple-point flaw in ceramics is developed and analyzed by finite-element elasticity. It is found that the Griffith theory applied to this model gives a fracture-damage criterion similar to that for open planar Griffith flaw, but the ratio of the stress for compressive damage to that for tensile fracture is somewhat more for the planar flaws. The study showed that the threefold model of the triple-point flaw does not predict behavior significantly different from the classical Griffith flaw model. It had been anticipated that it might predict that a much higher stress is needed to cause crack growth in compression.