Abstract
A novel technique for estimating critical sizes of the frontal process zone (FPZ) in ceramics is proposed using a single-edge V-notched beam (SEVNB) method. A three-point flexure test is carried out on ceramic specimens with sharp V-shaped notch. The critical local stress is calculated at a critical distance from the notch tip, where an exact solution for an elliptical hole in an infinite plate is used, based on a local fracture criterion. The critical size of the FPZ, fracture toughness, and flexural strength are estimated for several materials. The relationship between these mechanical properties indicated that there is an almost linear relationship between the fracture toughness and product of strength and square root of critical FPZ size, and that both the strength and critical size of the FPZ must be increased to enhance fracture toughness of ceramics.
