In this study, statistical fatigue tests in rotating bending were carried out by using round bar specimens of alumina ceramics, and the fatigue life distribution was examined at five stress levels by assigning 20 specimens at each level. Distribution characteristics of static bending strength were also examined, and the relationship between static and fatigue strengths was discussed as
P-S-N characteristics in a wide range of fatigue life. Furthermore, SEM observations of the fracture surfaces were made to investigate the effect of material defects on the fatigue life.
The main results obtained are summarized as follows;
(1) The distribution characteristics of static bending strength in alumina ceramics were well approximated by three-parameter Weibull distribution including a location parameter.
(2) The fatigue life of this material was also governed by three-parameter Weibull distribution, and its quantitative
P-S-N characteristics were obtained in a wide range of fatigue life, 1≤
N≤10
8.
(3) The fatigue life tends to increase with decrease of defect size, but it has a large scatter even if the defect size is same. This trend is more marked in the case of small defects.
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