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<p>In the fabrication of three-dimensional textile composites, needle-punching technology establishes initial interlaminar bonding through the introduction of Z-directional fibers. However, the Limited connection strength formed by this process constrains the optimization of the overall mechanical properties of preforms. To address this Limitation and enhance both interlaminar and in-plane mechanical performance of the reinforcement, this study integrates stitching technology with needle-punching, developing a 3D needled and stitched integrated process. To better understand how needling density and stitching density affect the tensile properties of three-dimensional needled and stitched preforms (3D-N&amp;SPs) and ceramic matrix composites, five groups of preforms and composites were designed and manufactured with varying processing parameters. To this end, we employ in-plane tensile testing alongside in-situ computerized tomography (CT) scans to thoroughly examine the mechanical responses and damage evolution patterns in these materials. The findings reveal that at a needling density of 35 pins/cm², the sample designated as P3, which features the highest stitching density, achieves a peak tensile strength of 26.8&#xa0;MPa. This improvement is primarily attributed to enhanced load transfer paths facilitated by the stitch threads. In contrast, within the needling density range of 30–35 pins/cm², Sample P4, which has a lower needling density, reaches a peak tensile strength of 21.11&#xa0;MPa. This performance advantage is essentially Linked to reduced fiber damage during processing. However, increasing both needling and stitching densities results in reduced tensile strength of composites. Consequently, reductions in tensile strength are observed, ranging from 8.1 to 9.0% for needling density and from 4.4 to 9.1% for stitching density. The performed CT analysis also indicates that the primary failure mechanism involved crack propagation along the axial direction of the Z-oriented needled fiber bundles, while the presence of pore defects exacerbates damage progression in the composite system.</p>

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Tensile Properties and Failure Mechanisms of Quartz Fiber Needled and Stitched Preforms and Composites

  • 期刊论文

  • 发表日期：

    2025年9月19日

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  • Yutong Shang,
  • Yifan Zhang,
  • Daijun Zhang,
  • Qiwei Guo,
  • Junhua Guo,
  • Chao Li,
  • Pengfei Jiang,
  • Yanfeng Liu,
  • Yumei Hao,
  • Xiaojia Wu,
  • Ning Wu,
  • Li Chen

摘要

In the fabrication of three-dimensional textile composites, needle-punching technology establishes initial interlaminar bonding through the introduction of Z-directional fibers. However, the Limited connection strength formed by this process constrains the optimization of the overall mechanical properties of preforms. To address this Limitation and enhance both interlaminar and in-plane mechanical performance of the reinforcement, this study integrates stitching technology with needle-punching, developing a 3D needled and stitched integrated process. To better understand how needling density and stitching density affect the tensile properties of three-dimensional needled and stitched preforms (3D-N&SPs) and ceramic matrix composites, five groups of preforms and composites were designed and manufactured with varying processing parameters. To this end, we employ in-plane tensile testing alongside in-situ computerized tomography (CT) scans to thoroughly examine the mechanical responses and damage evolution patterns in these materials. The findings reveal that at a needling density of 35 pins/cm², the sample designated as P3, which features the highest stitching density, achieves a peak tensile strength of 26.8 MPa. This improvement is primarily attributed to enhanced load transfer paths facilitated by the stitch threads. In contrast, within the needling density range of 30–35 pins/cm², Sample P4, which has a lower needling density, reaches a peak tensile strength of 21.11 MPa. This performance advantage is essentially Linked to reduced fiber damage during processing. However, increasing both needling and stitching densities results in reduced tensile strength of composites. Consequently, reductions in tensile strength are observed, ranging from 8.1 to 9.0% for needling density and from 4.4 to 9.1% for stitching density. The performed CT analysis also indicates that the primary failure mechanism involved crack propagation along the axial direction of the Z-oriented needled fiber bundles, while the presence of pore defects exacerbates damage progression in the composite system.