Analysis of impact damage mechanisms in aeronautical Cf/SiC composites via molecular dynamics simulation

To investigate the damage mechanisms of composite and monolithic materials under diamond shot impact, this study employs molecular dynamics simulations to construct models of diamond-tipped projectiles impacting Cf/SiC composites and pure carbon fiber (Cf) materials. A combination of hybrid potential functions is utilized to accurately describe interatomic interactions across different atomic species. By analyzing axial pressure, cross-sectional stress distribution, and load–displacement as well as load–stress curves, the impact-induced damage mechanisms in silicon carbide-doped carbon fiber materials are systematically examined. The results indicate that, with increasing impact depth, the stress diffusion radius in the Cf/SiC composite increases from 41.10 nm at 15 nm depth to 63.78 nm at 75 nm depth. In contrast, for the pure Cf material under the same conditions, the stress diffusion radius increases from 16.40 nm at 15 nm to 82.00 nm at 75 nm, demonstrating a significantly broader stress propagation zone. Moreover, the composite structure effectively mitigates damage in the peripheral regions, with edge stress values measured at ∼0.0101 and 0.0104 GPa—substantially lower than those observed in the monolithic Cf material under identical loading conditions. This study demonstrates that silicon carbide incorporation not only enhances the local strength and fracture toughness of carbon fiber materials but also inhibits the propagation of impact-induced damage. These findings provide valuable theoretical insights for the design and application of high-performance composite materials in advanced engineering contexts.