Mode I interlaminar performance and flexural performance of the novel gradient needle-punched composites with uniform transition

作者：Dili Zheng, Dongsheng Guo, J F Chen, Yasi Dong, Xiaoming Chen · 发表于：Journal of Composite Materials · 年份：2026 · DOI：10.1177/00219983261467147 · 研究领域：Mechanical Behavior of Composites、Fiber-reinforced polymer composites、Textile materials and evaluations

The existing gradient needle-punched fabric consists of layers of fiber felt and base fabric. The overall fiber volume fraction is relatively low, resulting in weak mechanical properties. Additionally, the density difference between the base fabric and the fiber felt is significant, making it difficult to achieve a uniform transition of the fiber volume fraction. This study presents a method for fabricating grid fabric-based gradient needle-punched preforms, leading to remarkable improvement in the mechanical properties of the preforms and their composites. Grid fabric-based gradient needle-punched fabrics and the corresponding composites were designed and fabricated. The effects of needle-punching parameters on fabric architecture, Mode I interlaminar fracture toughness, and composite flexural strength were systematically examined using micro-CT, DCB tests, three-point bending tests, and SEM fractographic analysis. Compared with traditional gradient needle-punched preforms, the fiber volume content at the back increased by 24.3%, and the average length of the back needle-punched fiber bundles increased by 11.1%. The Mode I interlaminar fracture toughness was improved by up to 221.5%, with flexural strength and modulus increasing by 30.9% and 21.0%. SEM fractographic analysis revealed that the dominant failure modes were fiber fracture and pullout.