Complete-Perforation Response of Hybrid Flax/Aramid–Epoxy Laminates Manufactured by Different Routes and Strike-Face Configurations

This study compares the complete-perforation response of flax/aramid–epoxy laminates manufactured with a fixed nominal 12-layer hybrid architecture while varying the manufacturing route and the reinforcement placed at the strike face. Laminates containing six flax and six aramid bidirectional fabric layers arranged in alternating two-layer blocks were produced by manual compression molding or vacuum-assisted hand lay-up and impacted with 9 mm full-metal-jacket projectiles. Five impacts were performed on one panel for each of four configurations; the shots were therefore treated as repeated observations within each panel rather than independent manufacturing replicates. Mean residual velocities ranged from 353.4 to 361.2 m/s, while mean projectile kinetic-energy losses ranged from 213.3 to 237.8 J. The VL panel (vacuum processed, flax strike face) showed the lowest mean residual velocity (353.4 m/s), whereas PA (compression molded, aramid strike face) showed the highest mean projectile kinetic-energy loss (237.8 J), closely followed by VL (236.0 J). Using the measured full-panel masses, mean SEA ranged from 0.970 kJ kg−1 for PA to 1.128 kJ kg−1 for VL. Post-impact inspection showed configuration-dependent visible surface-damage morphologies and projected damage-envelope areas; microscopic failure modes and internal delamination were not measured and are therefore not assigned from the photographs alone. Because every projectile completely perforated the targets, no experimental ballistic-limit velocity (V50) was determined. The results are presented as a descriptive, configuration-resolved comparison of the tested panels; independent panel replication is required for population-level inference on manufacturing-route and strike-face effects.