强噪声载荷下2D-C/SiC复合材料平板失效机理

A 2D-C/SiC composite panel is used in the thermal protection system of a hypersonic vehicle that is exposed to a combination of high force and temperature. Such an environment has a serious effect on the performance and structural dynamics of the panel. An acoustic test with an intensity ranging from 156 to 165 dB was carried out on a 2D-C/SiC panel. Its morphology before and after the test was obtained by infrared thermal imaging. The fracture morphology and the initiation and propagation positions of cracks were observed by SEM, and the failure mechanism of the 2D-C/SiC panel under strong acoustic loading was revealed. The composite panel showed fatigue failure caused by a combination of high frequency stretching and out-of-plane shearing. The former caused pull-out of carbon fibers and their brittle failure while the latter contributed to the rapid propagation of cracks.