Molecular dynamics simulations of hypersonic velocity impact protection properties of CNT/a-SiC composites

The hypersonic velocity impact protection properties of carbon-nanotube-reinforced amorphous silicon carbide composites are investigated using molecular dynamics simulation. The projectile-impact-induced damage to target materials is analyzed for composite targets having perpendicular and parallel alignments of carbon nanotubes with respect to impact direction, and compared to that of pristine amorphous silicon carbide target. It was found that, in the considered range of impact velocities, the penetration depth is approximately the same for both CNT-reinforced composites and pristine a-SiC target. At short time-scales, damage to a target is defined by penetration depth of projectile and density rearrangements taking place in the target material. In the composite with carbon nanotubes aligned parallel to the impact direction, a channeling of damage to deeper regions of the target occurs. In the case of perpendicular alignment, the damage is confined to a narrow region underneath the penetrating projectile. For both considered composite samples, we found that a significant damping of the amplitudes of compressive shock-waves takes place, thus reducing the special extent of damage in composites as compared to that in the pristine a-SiC target.