Reconstruction of meso-structure and numerical simulations of the mechanical behavior of three-dimensional four-directional braided ceramic matrix composites

Abstract

Textile-reinforced ceramic matrix composites are key structural materials for aerospace applications. In this paper, the influence of meso-structure and damage mechanisms on mechanical behavior of three-dimensional (3D) four-directional braided SiC/SiC composites is systematically investigated by using numerical simulations. First, periodic preform geometry model, also known as representative volume element (RVE), is reconstructed by using micro-computational tomography (μ-CT). Then, two damage mechanics models are employed to establish non-linear behavior of tows and matrix. Moreover, cohesive model is introduced to represent tow/tow and tow/matrix delamination behavior. It is noteworthy that homogenized tow model is derived from micromechanical model on fiber scale. Finally, macro stress-strain and failure behaviors of 3D braided SiC/SiC composites are simulated by meso-scale finite element analysis. Numerically simulated tensile modulus and strength of 3D braided SiC/SiC composites are compared with experimental results, exhibiting good consistency. Numerical simulations revealed failure mechanism and confirmed that, in addition to globally evolved damage process under tensile load, meso-scale preform caused stress concentration and subsequent local rupture behavior. Current research shows that reconstructed textile model realistically describes tensile mechanical behavior and damage evolution of 3D braided SiC/SiC composites.