ABSTRACT Three‐dimensional (3D) woven fabrics are composed of three sets of yarns, namely stuffer, binder, and filler, which are oriented in mutually perpendicular directions. 3D fabric composites can overcome the limitations of unidirectional (UD) and bidirectional (2D) composites by incorporating through‐thickness reinforcement. The focus of this research is to optimize the stuffer‐to‐binder (S:B) ratio and filler (pick) density in a 3D woven orthogonal fabric. Ultra‐high Molecular Weight Polyethylene (UHMWPE) yarn and epoxy resin were used as reinforcement and matrix, respectively, to manufacture composites using compression molding technique. The S:B ratio in 3D fabric preform was varied as 1:1, 2:1 and 4:1, and filler density was varied as 16, 20 and 24 cm −1 keeping four layers of fillers. Tensile, three‐point bending, in‐plane shear, low velocity impact, and dynamic mechanical tests were conducted to appraise the effect of preform structural parameters on the mechanical properties of the resultant composites. The results reveal that higher S:B ratio leads to higher ultimate tensile strength (UTS), tensile modulus, impact resistance, flexural strength and in‐plane shear strength. On the other hand, a higher filler density reduces the tensile modulus and improves impact resistance of composites. However, the influence of filler density on flexural and in‐plane shear properties of composites is dependent on the level of S:B ratio. The results reinforce the important roles of binder yarn crimp and the presence of resin‐rich regions in determining the mechanical properties of 3D woven fabric‐based composites.
Verma et al. (2026) studied this question.