Preforming is a common process in the manufacture of net-shaped composites, and there is a critical need for technologies that improve manufacturing speed without adversely impacting the interlaminar fracture toughness. Furthermore, composite structures that are repairable in-situ have potential for significant cost and performance benefits. This paper presents a new multi-functional composite system that combines ultra-high interlaminar fracture toughness with exceptional repair efficiency and is seamlessly integrated into the braiding process for rapid preform manufacture. The co-braided repair agent, EMAA, is shown to improve the interlaminar fracture toughness by over threefold, while enabling full recovery of the fracture properties via a thermal repair process. The resistance to crack initiation and crack propagation were strongly influenced by the geometric shape and spatial distribution of the EMAA which, in turn, was dictated by the preforming time. A new strategy is developed to produce a 3D fused EMAA network that enables the effective delivery of the repair agent into the delamination cracks and a greater than 100% recovery to the steady-state fracture toughness following delamination repair. The EMAA composites developed in this study exhibited repeated (at least three cycles) in-situ delamination repair abilities.

预成型是制造网状复合材料的常用方法，因此迫切需要能够提高制造速度而不会对层间断裂韧性产生不利影响的技术。此外，可现场修复的复合结构具有显着的成本和性能优势的潜力。本文提出了一种新型的多功能复合材料系统，该系统结合了超高的层间断裂韧性和出色的修复效率，并无缝集成到编织过程中，可快速制造瓶坯。已证明，共编织修复剂EMAA可将层间断裂韧性提高三倍以上，同时可通过热修复工艺使断裂性能完全恢复。EMAA的几何形状和空间分布强烈影响了裂纹萌生和裂纹扩展的能力，而EMAA的几何形状和空间分布又由预成型时间决定。开发了一种新的策略来生产3D熔融EMAA网络，该网络能够将修复剂有效地输送到分层裂纹中，并在分层修复后将稳态断裂韧性恢复到100％以上。在这项研究中开发的EMAA复合材料表现出重复性（至少三个周期）原位分层修复能力。