Laminar carbon fibre reinforced polymer (CFRP) composites contain inherent weak ply interfaces due to the lack of through-thickness fibre reinforcement. In this study, all ply interfaces were interleaved with ultra-thin (13 μm) non-woven short aramid fibre (SAF) veils to generate across ply fibre bridging, formed in-situ by movements of free fibre ends during the composite forming process. The toughening effect of ultra-thin SAF veils (13 μm and 29 μm in thickness) before and after impact was measured and compared. It was found that the 13 μm SAF veils increased the bulk flexural strength and modulus of CFRP by 16.9% and 19.8% prior to impact, challenging the common belief that interleaving with micro-length or short fibres is only beneficial to post-impact properties. X-ray micro-computed tomography and cross-section microscopy examinations were used to explain the mechanisms for improved flexural properties before and after low-velocity impact.

层状碳纤维增强聚合物（CFRP）复合材料由于缺乏贯穿厚度的纤维增强，因此具有固有的薄层界面。在这项研究中，所有层界面都与超薄（13μm）无纺短芳族聚酰胺纤维（SAF）面纱交错插入，以在整个层纤维桥接中生成，该层桥接是在复合材料成型过程中通过自由纤维端部的运动原位形成的。测量并比较了冲击前后的超薄SAF面纱（厚度分别为13μm和29μm）的增韧效果。发现13μmSAF面纱在撞击前将CFRP的整体抗弯强度和模量提高了16.9％和19.8％，这挑战了人们普遍认为与微长或短纤维交织仅对碰撞后性能有利的观念。