Tensile damage mechanism analysis and mesoscale modeling of plain-woven SiCf/SiC ceramic matrix composite based on in-situ synchrotron radiation experiments

By conducting in-situ tensile experiments using synchrotron radiation technique, a three-dimensional (3D) dynamic microscopic damage process was observed for the plain-woven SiC f /SiC ceramic matrix composite, contributing to the quantitative characterization of the dynamic evolution of the 3D morphology of fiber bundles, and the tensile damage mechanisms of plain-woven SiC f /SiC composites were revealed, while the mesoscale modeling was performed. Firstly, in-situ tensile experiments were carried out on the plain-woven SiC f /SiC composite, and sliced images under several holding loads during the tensile process were taken through synchrotron radiation X-ray computed tomography (SR-CT). Morphological parameters, including the cross-sectional area, fiber bundle centerline tortuosity, and porosity, were statistically analyzed from the segmented CT images at the initial load and pre-fracture load. The observation results reveal that the tensile damage mechanism of the plain woven SiC f /SiC composite at room temperature is dominated by the "fiber bundle flattening, pore propagation and interlaminar crack" mechanism. Then, the mesoscale simulation modeling was carried out to reproduce the damage mechanism based on the CT images, in which a hexahedral mesh model constructed using a virtual fiber compaction method was employed to predict the damage volume changes. Compared with the experimental results, the absolute error of the predicted increment for the total volume porosity is less than 1 %. The proposed "in situ observation - morphological quantification - mechanism driven model validation" framework was applied to characterize the damage mechanisms of the studied plain-woven SiC f /SiC composite, providing insights in damage evolution assessment and life prediction for ceramic matrix composite in aeroengine.