# Quasi-Static Penetration Properties of 3D-Printed Composite Plates

## TL;DR

This study explores how 3D-printed composite plates resist impact and piercing loads, showing that continuous fiber reinforcement significantly improves their energy absorption capabilities.

## Contribution

The study demonstrates that FFF-printed composites with continuous fibers can match traditional composites in energy absorption, despite lower fiber volume fractions.

## Key findings

- Continuous fiber reinforcement increased quasi-static energy absorption by 20–185% compared to short-fiber-reinforced plates.
- FFF-printed composites with continuous fibers showed normalized energy absorption comparable to traditional composites.
- The study confirms the potential of FFF as a promising additive manufacturing technique for impact-resistant composites.

## Abstract

This work investigated the impact and piercing load resistance (energy absorption capabilities) of 3D-printed composites plates manufactured by means of the Fused-Filament-Fabrication (FFF) technique. Two sets of reinforced composite plates were produced. The first set of plates was printed with short-carbon-fiber-reinforced polyamide-12, while the second set was reinforced with continuous fibers. The plates were tested with quasi-static indentation tests at various Span-to-Punch ratios and with three different indenter nose shapes (blunt, hemispherical, and conical). The quasi-static measurements were subsequently elaborated to estimate the energy absorption capability of the plates during a ballistic impact. The addition of continuous fibers increased the quasi-static energy absorption capability by 20–185% with respect to the short-fiber-reinforced plates. The quasi-static results showed that by including the continuous reinforcement in the plates, the normalized energy absorbed increased by an order of magnitude. Finally, a comparison with data from the literature concerning continuous-reinforced composite plates manufactured by means of traditional techniques was carried out. The comparison revealed that FFF-printed composite plates can compete with traditional composite ones in terms of both ballistic and quasi-static penetrating load conditions, even if limited by the lower fiber volume fraction. Thus, these findings confirm that this novel Additive Manufacturing technique is promising and worth investigating further.