Stress field and damage evolution in C/SiC woven composites: Image-based finite element analysis and in situ X-ray computed tomography tests

The construction and examination of meso-structural finite element models of a Chemical-Vapor-Infiltrated (CVI) C/SiC composite is carried out based on X-ray microtomography digital images (IB-FEM). The accurate mesostructural features of the C/SiC composites, which are consisted of carbon fiber tows and CVI-SiC matrix, in particular the cavity defects, are reconstructed. With the IB-FEM, the damage evolution and fracture behaviors of the C/SiC composite are investigated. At the same time, an in situ tensile test is applied to the C/SiC composite under a CT real-time quantitative imaging system, aiming to investigate the damage and failure features of the material as well as to verify the IB-FEM. The IB-FEM results indicate that material damage initially occur at the defects, followed by propagating toward the fiber-tow/SiC-matrix interfaces, ultimately, combined into macrocracks, which is in good agreement with the in situ CT experiment results.

Automated summary

This study constructed and examined meso-structural finite element models of CVI C/SiC composite based on X-ray microtomography digital images. Using the IB-FEM method, the damage evolution and fracture behaviors of the composite were investigated, with in situ tensile testing conducted to verify the model. The results showed that material damage initiated at defects and propagated towards interfaces, eventually forming macrocracks, consistent with in situ CT experiment results.