基于声发射(AE)信号和计算机断层扫描(CT)成像技术,开展了高温复合材料的内部损伤状态分析。通过声发射技术获得复合材料损伤时的宏观应力波信号,分析得到声发射信号的频率等波形特征参数;通过计算机断层扫描得到复合材料结构内部微细观三维损伤图像,判断存在的损伤类型。结果表明,不同工艺陶瓷基高温复合材料在拉伸载荷下,内部会产生不同类型的损伤,纤维束与基体之间的脱黏开裂所对应的声发射信号特征频率为44 kHz,基体失效的特征频率为150 kHz,纤维束断裂损伤的特征频率为250 kHz。

The damage characteristics of the acoustic emission signals produced in high temperature ceramic matrix composites were analyzed based on the relations between acoustic emission (AE) signals and X-ray CT images. The characteristic parameters including the frequencies of AE signals were obtained by analyzing the signals of macroscopic stress waves in the case of composite damage by using AE technology. Existing damage types can be confirmed by the microscopic 3D damage images of composite structures were obtained by CT method. The results showed that different types of damage can generate in the interior of ceramic matrix composite specimens fabricated by different processing techniques under tension load. The corresponding frequency of AE signals for the delaminations between fiber bundles and the matrix damage and fiber bundle fracture were respectively 44 kHz, 150 kHz and 250 kHz.