PROOF TESTING OF CERAMIC MATERIALS SUBJECTED TO CYCLIC LOADING

A numerical simulation for two distinct materials and an experiment using an alumina were conducted to investigate the effect of the stress rate in a proof testing on the subsequent fatigue behavior. The simulated result revealed that as increasing the unloading stress rate the minimum life became longer and finally approached to the largest value, while the minimum life was not affected by the loading stress rate. In the experiment, the proof testing was found not to be efficient for the subsequent fatigue properties unless the unloading stress rate was selected to be adequately higher. The life distribution could be estimated by the band region between two extreme distributions associated with the crack geometry.