Projectile Shape Effects in Hypervelocity Impact of Honeycomb-Core Sandwich Structures

Honeycomb-core sandwich structures are commonly utilized as orbital debris shielding in unmanned satellites. This study investigated the effects of projectile shape on the ballistic performance of aluminum honeycomb-core sandwich panels subjected to 7 km/s (hypervelocity) impacts at normal incidence. The shape of the reference projectile was a sphere, and other projectiles had a disk topology, including simple disks and disks with a central hole (ring projectiles), with different aspect ratios. To facilitate the investigation, a numerical simulation model was developed and verified against experimental data and predictions from an empirical ballistic limit equation. The verified model was then used to investigate hypervelocity impact scenarios involving different projectile shapes, honeycomb grades with different cell sizes, and different projectile/honeycomb cell alignments. It was found that of the shapes considered here, ring projectiles were of the highest concern: the volume of a 7 km/s ring projectile that could be resisted by a honeycomb-core sandwich panel without perforation of the rear facesheet was 1.65 times lower than that of a spherical projectile. In contrast, simulations with simple disks (without a central hole) did not show any significant change in the ballistic performance of the panel compared to impacts with a spherical projectile. Additional simulations conducted with ring projectiles demonstrated the strong influence of honeycomb cell size and projectile/honeycomb cell alignment on damage to the rear facesheet of the panel. (C) 2021 American Society of Civil Engineers.

Automated summary

This study investigated the effects of projectile shape on the ballistic performance of aluminum honeycomb-core sandwich panels under hypervelocity impacts. Ring projectiles were found to be of the highest concern, while simulations with simple disks did not show significant changes in the panel's performance. Additionally, honeycomb cell size and projectile/honeycomb cell alignment strongly influenced damage to the rear facesheet of the panel.