Ply‐Count Effects on Tensile Performance of <scp>FDM 3D</scp> ‐Printed Glass Fiber Hexagonal Honeycombs

ABSTRACT Continuous fiber‐reinforced 3D printed honeycombs are a core research focus for aerospace lightweight load‐bearing applications. Ply count, a critical design parameter, still lacks systematic quantitative data on its tensile performance regulation rules and underlying failure mechanisms. This study investigates regular hexagonal high‐strength high‐temperature (HSHT) glass fiber‐reinforced Onyx honeycombs fabricated via fused deposition modeling (FDM), combining quasi‐static tensile tests, SEM characterization, and ply‐correlated finite element simulations. Results show increasing ply count improves elastic modulus by 663% and peak tensile stress by 350% within the test range. Energy absorption gains are prominent for 0–16 plies, then narrow sharply for 24 and 40 plies. Failure modes shift sequentially from matrix‐dominated fracture to intermediate‐ply fiber tow co‐fracture, then widespread 40‐ply interfacial debonding, validated by fiber pull‐out statistics. The developed finite element model has a 21.4% range‐normalized root mean square error, qualitatively capturing the overall upward trend in tensile strength with increasing ply count and the diminishing strength returns at high ply counts, offering guidance for composite honeycomb optimization for uses including drone wings.