Cross–Multiscale Mechanical Behavior of Carbon Fiber/Silicon Carbide Composites used in Spacecraft Nozzle Throat Liners

This study presents a novel cross-multiscale modeling framework for carbon fiber reinforced silicon carbide (C/SiC) composites.A systematic series of representative volume elements (RVEs) was constructed, spanning from a microscopic RVE of a single carbon fiber in a silicon carbide matrix (RVE1), to mesoscopic RVEs of a fiber bundle (RVE2) and woven fiber bundles (RVE3), and further to macroscopic single-layer and multi-layer models based on RVE3.The anisotropic mechanical behavior of the C/SiC composites was investigated through a hierarchical analysis that integrates mesoscopic mechanics theory with both periodic and non-periodic finite element simulations.The tensile and compressive properties were experimentally validated via in-situ digital image correlation (DIC) testing, providing a direct link between simulation and experiment.This integrated approach elucidates the fundamental mechanical properties and failure mechanisms of C/SiC composites across scales.The key contributions are: (1) the development of a cross-multiscale modeling and simulation methodology; (2) the multi-scale morphological characterization and analysis; and (3) the revealed tensile/compressive properties and associated failure mechanisms.The findings provide important insights for cross-scale modeling, macroscopic model equivalence, and accurate material parameter calibration in fiber-reinforced composites for aerospace applications.