加载速率对Al_2O_3陶瓷弯曲切口强度及其概率分布的影响

EFFECT OF LOADING RATE ON FLEXURE NOTCH STRENGTH AND ITS STATISTICAL DISTRIBUTION OF Al_2O_3 CERAMICS

测定了 Al2 O3陶瓷在不同恒位移加载速率作用下的弯曲强度和弯曲切口强度。结果表明 ,不同切口的实际应力速率可由试验记录的载荷 -时间曲线确定。在实验的四种加载速率下(0 .0 5,0 .5,5和 50 mm/min) ,其弯曲强度、弯曲切口强度均同时符合正态分布、对数正态分布和Weibull分布。加载速率在 0 .0 5～ 5mm/min,其弯曲强度、弯曲切口强度符合本文给出的陶瓷材料切口强度的表达式。从而实现了用光滑试件的断裂强度及其概率分布预测切口强度及其概率分布 。

Flexure strength and flexure notch strength of Al 2O 3 ceramics were measured under bend loading rate between v=0.05-50mm/min. The stress rate of notch specimen could be calculated from bend load vs. time curve. Test results and analysis showed that both the flexure strength and flexure notch strength, under all testing conditions, followed the normal distribution, the log normal distribution and weibull distribution. In the range of v=0.05-5mm/min, flexure strength and the flexure notch strength followed the notch strength equations of ceramics. The equations on the notch strength of ceramic materials provided the basis to design the ceramics structural members and to assess the reliability of safety.