SiCf/SiC陶瓷基复合材料T型结构件在弯曲载荷下的失效行为研究

Failure Behavior of SiCf/SiC T-Pieces Specimens under Bending Load

关键词:  陶瓷基复合材料  T型结构件  弯曲载荷  数字图像相关技术  失效分析

Key words:  Ceramic matrix composition  T-piece specimens  Bending load  DIC  Failure analysis

摘要:

为了揭示SiC_f/SiC陶瓷基复合材料（CMCs）T型结构件在发动机服役载荷下的失效模式及承载水平，利用数字图像相关技术（DIC）研究了室温及高温环境下T型结构件在弯曲载荷下的失效行为，开展了T型结构件在室温、900℃以及1200℃下的静强度试验。DIC及断口分析结果表明，T型结构模拟件在弯曲载荷下底板首先出现分层，并沿着结合面向外扩展。随着载荷进一步增大，底板和肋板的倒圆位置出现径向裂纹，T型结构件承载能力迅速下降。T型结构件在900℃下的最大承载能力为室温的73.2%，1200℃下的最大承载能力为室温的59.1%。

Abstract:

In order to reveal the failure mode and bearing level of SiC_f/SiC ceramic matrix composites （CMCs） T-pieces structure under engine service load， the failure behavior of T-pieces specimens under bending load at room temperature and high temperature was studied by using digital image correlation technology （DIC）. The static strength tests of T-piece specimens were completed at room temperature， 900℃ and 1200℃. DIC and fracture analysis show that delamination would first start at the intersection area of bottom plate and then extend outward along the bonding surface. When the load continues to increase， radial cracks appeared at the rounding position of the bottom plate and rib plate. The maximum load-carrying capacity of T-piece specimens decreased with the crack appeared. The results show that the maximum load-carrying capacity of T-piece specimens at 900℃ is 73.2% of one at room temperature and 59.1% of room temperature value at 1200℃.