Effects of Weave Structure, Weft Density, Laying Method, and Gradient Structure on the Ballistic Performance of <scp>3D</scp> Angle‐Interlock Aramid/Epoxy Composites

ABSTRACT Although conventional two‐dimensional fiber‐reinforced polymer composites are commonly used in ballistic protection, they frequently suffer from delamination and poor in‐plane shear performance. Herein, we developed a three‐dimensional angle‐interlocked (3DAI) aramid/epoxy composite for bulletproof vehicle applications. The ballistic performance of the 3DAI composites is critically influenced by their programmable fabric structure, laying methods (unidirectional, orthogonal, symmetric, and sandwich), and gradient structures utilizing stacking layers with varying weft densities. The 3DAI aramid/epoxy composite exhibits superior ballistic performance, structural design flexibility, delamination resistance, and a smaller damage area, along with a reduction in the number of layers required compared to plain weave composites. The high‐weft‐density composites demonstrated the best overall ballistic performance and the highest resistance to impact deformation. The orthogonal configuration strategy was found to be the most effective in dissipating energy and provided the optimal ballistic protection. Moreover, the graded structure integrating high‐ and low‐weft‐density layers exhibited superior ballistic performance relative to the uniform design. The best anti‐denting performance was achieved when the high‐weft‐density layer was placed on the bullet‐facing side and the low‐weft‐density layer on the back side. These findings provide new insights into the armor‐grade composite and advanced ballistic composites.