A simple method for studying K(R)-curves of crack propagation resistance in ceramic materials

The simple method presently devised for studies of the stress-intensity factor K(R) in ceramic materials does not require periodic measurements of crack-length increment in the process of subcritical propagation, and is based on the discovery of a relationship between the load increment and the nonlinear deflection increment. The method's consistency is implicit in the results obtained for ZrO2 ceramics and a LaCrO3-Cr composite. The primary limitation in the application of this method lies in the assumption of a crack increment which is small relative to its initial length. (O.C.)