Understanding interlaminar toughening of unidirectional CFRP laminates with carbon nanotube veils
Understanding interlaminar toughening of unidirectional CFRP laminates with carbon nanotube veils
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DOI：
10.1016/j.compositesb.2020.108372
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发表时间：
2020-11-15
影响因子：
13.1
通讯作者：
Vilatela, Juan Jose
中科院分区：
文献类型：
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作者：
Ou, Yunfu;Gonzalez, Carlos;Vilatela, Juan Jose
纳米结构夹层的引入是结构复合材料层间增强最有前途的策略之一。在这项工作中，我们研究了失效机制和层间微观结构的航空级结构复合材料增强薄面纱的碳纳米管生产的工业化纺丝工艺。采用热压法制备了不同组分碳纳米管（CNT）纱网交织的单向碳纤维/环氧树脂基复合材料样品，并测试了在模式I（开口）和模式II（面内剪切）下测量的层间断裂韧性（IFT），以及通过短梁剪切（SBS）测试评价的层间剪切强度（ILSS）。裂纹扩展模式可以直接确定通过断口分析，电子显微镜和树脂/CNT空间歧视的拉曼光谱，显示了层间增强和之间的平衡之间的明确的相关性内聚/粘合失效模式在层间区域。具有CNT面纱的完全树脂渗透的复合材料使模式II IFT（88%）大幅度增加至1500 J/m（2），并且表观层间剪切强度略有增加（6.5%），但模式I IFT降低（-21%）。韧化因子，定义为相对增加的韧性每interleaf层厚度比，给出了创纪录的高值15.8模式II IFT。结果有助于建立层间渗透，层间交叉和形成碳纤维桥接的作用，层间增强与夹层。
The introduction of nanostructured interlayers is one of the most promising strategies for interlaminar reinforcement in structural composites. In this work, we study the failure mechanism and interlayer microstructure of aerospace-grade structural composites reinforced with thin veils of carbon nanotube produced using an industrialised spinning process. Samples of unidirectional carbon fiber/epoxy matrix composites interleaved with different composition CNT veils were prepared using hot press method and tested for interlaminar fracture toughness (IFT), measured in Mode-I (opening) and Mode-II (in-plane shear), and for interlaminar shear strength (ILSS), evaluated by the short beam shear (SBS) test. The crack propagation mode could be directly determined through fractography analysis by electron microscopy and resin/CNT spatial discrimination by Raman spectroscopy, showing a clear correlation between interlaminar reinforcement and the balance between cohesive/adhesive failure mode at the interlayer region. Composites with full resin infiltration of the CNT veils give a large increase of Mode II IFT (88%) to 1500 J/m(2) and a slight enhancement of apparent interlaminar shear strength (6.5%), but a decrease of Mode I IFT (-21%). A toughening factor, defined as the relative increase in toughness per interleaf-to-ply thickness ratio, give a record-high value of 15.8 for Mode II IFT. The results help establish the role of interlayer infiltration, interlaminar crossings and formation of a carbon fiber bridgings, for interlaminar reinforcement with interleaves.