Fatigue of Ceramics (Part 2)

To investigate the fatigue strength in the S-N curve of ceramic materials, the high speed cyclic fatigue testing technique was developed using the resonant bending method, and the cyclic fatigue test up to 1010 cycles was conducted. To compare with the resonant bending fatigue tests at 3kHz, the alternating cantilever bending fatigue tests were carried out at 20Hz, 0.3Hz and 0.03Hz with the same specimen using an electro-hydraulic fatigue testing machine. Cyclic fatigue at room temperature depended mainly on the number of cycles accumulated rather than on time. The distributions for the fatigue life were presented in Weibull plots with three parameters. From the predicted fatigue life limit at each stress amplitude, the fatigue strength limit was estimated to be about 40% of the initial bending strength.