Damage-Resistant Composites Using Electrospun Nanofibers: A Multiscale Analysis of the Toughening Mechanisms
Damage-Resistant Composites Using Electrospun Nanofibers: A Multiscale Analysis of the Toughening Mechanisms
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DOI：
10.1021/acsami.6b02247
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发表时间：
2016-05-11
影响因子：
9.5
通讯作者：
De Clerck, Karen
中科院分区：
文献类型：
--
作者：
Daelemans, Lode;van der Heijden, Sam;De Clerck, Karen
如今，纤维增强聚合物复合材料是在最小重量下需要高刚度和强度的应用中的标准材料，例如航空航天结构，超轻型车辆，甚至是用于高效储能系统的飞轮。虽然纤维增强聚合物复合材料与其他材料相比显示出许多优点，但增强层之间的分层仍然是限制进一步突破的主要问题。已经提出的用于使增强帘布层之间的层间区域变韧的传统解决方案已经达到其极限或具有重要的缺点，例如高成本或需要适应的生产工艺。最近，静电纺丝纳米纤维被认为是一种更可行的层间增韧方法。虽然预期的好处很多，但对电纺纳米纤维面纱增强复合材料层压板的研究仍然非常有限。到目前为止，已经完成的工作几乎完全集中在不同种类的纳米纤维的层间断裂韧性测试上，其中通常使用试错法。深入了解细观力学断裂机制和获得增韧复合材料的参数还没有报道，但它是至关重要的，以推进研究和设计高抗损伤复合材料。本文通过对几种不同类型的铝合金在三个不同层次上的增韧效果进行分析，提供了这样的见解。只有把不同层次的结果结合起来，才能得到透彻的理解。这些水平对应于复合材料的分层性质：层压板、层间区域和基体树脂。结果发现，每个级别对应于某些机制，导致增韧效果。静电纺丝纳米纤维对微裂纹的桥接是其抗损伤的主要增韧机制。然而，每一比额表的桥接机制表达方式不同，并取决于与某一比额表有关的参数。因此，本文中报告的增韧机制的多尺度分析是至关重要的了解增韧复合材料的行为，并因此允许设计新颖的，耐损伤的，纳米纤维增韧材料。
Today, fiber-reinforced polymer composites are a standard material in applications where a high stiffness and strength are required at minimal weight, such as aerospace structures, ultralight vehicles, or even flywheels for highly efficient power storage systems. Although fiber-reinforced polymer composites show many advantages compared to other materials, delamination between reinforcing plies remains a major problem limiting further breakthrough. Traditional solutions that have been proposed to toughen the interlaminar region between reinforcing plies have already reached their limit or have important disadvantages such as a high cost or the need for adapted production processes. Recently, electrospun nanofibers have been suggested as a more viable interlaminar toughening method. Although the expected benefits are numerous, the research on composite laminates enhanced with electrospun nanofibrous veils is still very limited. The work that has been done so far is almost exclusively focused on interlaminar fracture toughness tests with different kinds of nanofibers, where typically a trial and error approach has been used. A thorough understanding of the micromechanical fracture mechanisms and the parameters to obtain toughened composites has not been reported as of yet, but it is crucial to advance the research and design highly damage-resistant composites. This article provides such insight by analyzing the nanofiber toughening effect on three different levels for several nanofiber types. Only by combining the results from different levels, a thorough understanding can be obtained. These levels correspond to the hierarchical nature of a composite: the laminate, the interlaminar region, and the matrix resin. It is found that each level corresponds to certain mechanisms that result in a toughening effect. The bridging of microcracks by electrospun nanofibers is the main toughening mechanism resulting in damage resistance. Nevertheless, the way in which the nanofiber bridging mechanism expresses itself is different for each scale and dependent on parameters linked to a certain scale. The multiscale analysis of the toughening mechanisms reported in this paper is therefore crucial for understanding the behavior of nanofiber toughened composites, and as such allows for designing novel, damage-resistant, nanofiber-toughened materials.