Novel 3D tailored discontinuous fibre preforms for a sustainable future in composite manufacturing

新型 3D 定制不连续纤维预制件，实现复合材料制造的可持续未来

• 批准号: EP/W020688/1
• 负责人: HaNa Yu
• 金额: $ 43.79万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW020688%2F1
• 关键词: Novel; 3D; tailored; discontinuous; fibre

Fibre reinforced polymer composites offer outstanding strength, stiffness and low weight, and their use has increased rapidly in various sectors such as aerospace and automotive. However, the long fibre reinforcements significantly limit the formability of composite materials hence the processability. This fundamental problem can be resolved by changing the reinforcements to short fibres (i.e. a few mm long) provided that the short fibres are highly aligned to minimise the fibre length effect on the mechanical properties of the final parts. Although highly aligned short fibre composites and their manufacturing processes therefore have regained attention, the produced preform is a sheet or tape, and these intermediate materials end up being used as the same way as long fibre reinforced composite fabrication methods: cutting, stacking, forming, and curing. This conventional composite fabrication method still produces a large amount of waste in production even when using aligned short fibre preforms or prepregs. Furthermore, fibre reinforced composite products are prone to crack or fail during post-processes such as drilling or machining. Lack of mechanical properties in the through-thickness direction is also a critical challenge in composite products. The through-thickness reinforcement concept to improve interlaminar shear strength, out-of-plane stiffness, and fracture toughness in fibre reinforced composite materials is not new. However, this has not been achieved yet in a single manufacturing process for aligned short fibre composites. Then, what if highly aligned short and discontinuous fibre composites can truly replace long and continuous fibre composites in engineering applications? Wouldn't it be possible to create a more sustainable future in composite manufacturing? The vision of this research is to answer these questions. The proposed research will innovate the fabrication process for discontinuous fibre composites assisted with additive manufacturing technique. The new technology will realise an automated process capable of manipulating the discontinuous fibre orientation and preform density (volume fraction) during operation following the fibre angle distribution optimal for formability and structural properties required in the final products. It will not only reduce a number of manufacturing steps such as preforming, cutting, placing, and trimming but also minimise the waste in production.To achieve the aim, a new short fibre orientation head will be developed based on a novel 3D fibre orientation mechanism. The unique alignment mechanism and its control programme will enable high-precision localised control of in-plane and out-of-plane fibre orientations as well as fibre volume fraction. The fibre orientation head will be then placed onto a CNC platform to fully automate production of 3D tailored preforms directly from the raw short fibres. The process validation will be performed by assessing the 3D microstructure of the produced preforms via CT scanning. Then the research will quantify the benefit of the 3D structured short fibre preforms and their composites for improving mechanical and structural properties.

纤维增强聚合物复合材料具有出色的强度、刚度和低重量，其在航空航天和汽车等各个领域的应用迅速增加。然而，长纤维增强显著地限制了复合材料的可成形性，因此限制了可加工性。这个基本问题可以通过将增强物改变为短纤维（即几mm长）来解决，只要短纤维高度对齐以使纤维长度对最终部件的机械性能的影响最小化。虽然高度对齐的短纤维复合材料及其制造工艺因此重新受到关注，但生产的预制件是片材或带材，并且这些中间材料最终以与长纤维增强复合材料制造方法相同的方式使用：切割，堆叠，成型和固化。这种传统的复合材料制造方法即使在使用对齐的短纤维预成型件或预成型件时，在生产中仍然产生大量的浪费。此外，纤维增强复合材料产品在诸如钻孔或机加工的后处理期间易于破裂或失效。在整个厚度方向上缺乏机械性能也是复合材料产品的关键挑战。提高纤维增强复合材料层间剪切强度、平面外刚度和断裂韧性的全厚度增强概念并不新鲜。然而，这还没有在用于对齐的短纤维复合材料的单个制造过程中实现。那么，如果高度排列的短纤维和不连续纤维复合材料能够在工程应用中真正取代长纤维和连续纤维复合材料呢？难道不可能在复合材料制造业中创造一个更可持续的未来吗？本研究的目的就是回答这些问题。该研究将创新非连续纤维复合材料的制造工艺，并辅以增材制造技术。该新技术将实现一种自动化工艺，能够在操作过程中操纵不连续纤维取向和预成型件密度（体积分数），遵循最终产品所需的成形性和结构性能的最佳纤维角分布。它不仅可以减少预成型、切割、放置和修整等制造步骤，而且可以最大限度地减少生产中的浪费。为了实现这一目标，将开发一种基于新型三维纤维定向机构的新型短纤维定向头。独特的对齐机制及其控制程序将能够对面内和面外纤维方向以及纤维体积分数进行高精度局部控制。然后将纤维定向头放置在CNC平台上，以完全自动化地直接从原始短纤维生产3D定制预制件。将通过CT扫描评估生产的预制件的3D微观结构来进行工艺验证。然后，该研究将量化3D结构短纤维预制件及其复合材料在改善机械和结构性能方面的好处。