强噪声激励下C/SiC复合材料壁板动态响应与失效分析

高超声速飞行器热防护系统和热结构包含多种形式的复合材料薄壁结构，对巡航或再入飞行中的强噪声环境十分敏感和易发生失效破坏，严重威胁着飞行器结构的完整性和可靠性。为考核复合材料薄壁结构的耐噪声性能，基于高声强行波管噪声试验系统，选取厚度为1~3 mm的C/SiC复合材料平板作为试验件，试验件四周采用螺栓进行固定安装。通过开展156~165 dB噪声激励动态响应试验，获得了不同量级噪声作用下的动态响应变化规律。针对厚度为1 mm的试验件开展了失效试验，在168 dB噪声作用下，试验件发生了迅速破坏，采用红外无损检测设备对失效后的C/SiC复合材料平板进行检测，采用SEM对断面形貌进行观察，揭示出强噪声激励下的失效模式，可为高温复合材料结构优化设计和耐噪声失效性能评估提供技术支撑。 

Dynamic responses and failure analysis of C/SiC composite plates subjected high intensity acoustic loads

Thermal protection systems and hot structures of hypersonic vehicles include many composite plates. These structures are very sensitive to acoustic loads during cruise or re-entry flights and are destroyed easily. It is a vital challenge for the integrity and the durability of hypersonic vehicle plates. The C/SiC composite testing flat plates with thickness from 1 mm to 3 mm were chosen and many acoustic tests were carried out using a progressive wave tube facility. The four edges of these flat plates were completely fixed using fastening bolts. Responses of acceleration and strain of the C/SiC composite testing plates within 156-165 dB acoustic loads were obtained. The C/SiC composite testing plate with the thickness of 1 mm was destroyed rapidly subjected acoustic load with sound pressure level 168 dB. The failure plate was detected using the infrared nondestructive devices and the fracture surface was observed using SEM, then the failure modes of the testing plate were also achieved. The results are significant to optimum designs and anti-acoustic failure evaluation for high temperature material structures.