Exploratory ballistic evaluation of eucalyptus-dyneema hybrid composite armour

This study reports the development and ballistic evaluation of hybrid composite armour panels using plain-weave eucalyptus fabric and unidirectional dyneema (layer) in an epoxy matrix. Four configurations with different stacking ratios, plus a dyneema control, were made via compression moulding. Panels were tested using methodologies adapted from NIJ 0101.06 and BIS 17051:2018 standards against 9 mm × 19 FMJ projectile threat. Results show all samples recorded a back face signature (BFS) below the 44 mm threshold. The 30 eucalyptus +20 dyneema layer panel was most effective, reducing BFS by 31% (19.60 ± 3.76 mm) and depth of penetration (DOP) by 52% (9.02 ± 3.65 mm) compared to the dyneema control. Achieving this required a 42.6% reduction in areal density normalised incident energy ( E n o r m ), safely balancing required kinetic energy arrest with the structural mass needed to prevent blunt-force trauma. Instrument analysis (VSC 8000 HS, SEM, 3D-CT, FTIR, DSC) revealed a dual energy dissipation mechanism: eucalyptus layers cause projectile blunting and brittle shear fractures, while dyneema absorbs impact energy through thermal melting and chain yielding. Incorporating biomass up to 33.4%, these hybrid composites demonstrate effective ballistic performance and meet structural protection needs, laying a foundation for future hybrid/green armour advancements.