Braided thermoplastic composite rivets for composite structures

现代飞机结构的一个重要部分是使用复合材料制造的。这些材料坚硬而坚固，同时比传统航空航天制造中常用的铝、钛或钢等金属材料更轻。复合材料部件必须使用重型钛紧固件组装，因为结构边界不能由政府当局认证。此外，钻孔精度要求比金属结构紧固高得多。本研究计画将开发一种复合材料结构用铆钉。铆钉毛坯将采用脉冲制造技术生产。纸浆必须适应先进的材料，如PEEK聚合物和编织碳纤维。利用双轴向编织物的可变形性的铆钉设置操作将 放宽钻孔精度要求。复合材料铆钉将由与周围复合材料结构相似的材料制成，从而消除电偶腐蚀问题。此外，复合铆钉的低导电性将减轻使用金属紧固件时与静电放电相关的风险。为了研究和确定最佳铆接参数，设计了一台机器人化铆接机。简单的接头配置的机械性能将被表征。实现这些目标将使我们能够开发一种新技术，该技术有可能降低与钻孔和组装相关的成本，提高安全性，降低飞机重量。

A significant part of modern aircraft structures are fabricated using composites materials. These materials are stiff and strong while being lighter than metallic materials such as aluminum, titanium or steel commonly used in traditional aerospace manufacturing. Composite material components must be assembled using heavy titanium fasteners since structural bounding is not certifiable by governmental authorities. Moreover, the drilling precision requirements are much greater than for metallic structure fastening. This research project will develop a composite rivet for composite structures. Rivet blanks will be produced using the pultrusion manufacturing technique. Pultrusion must be adapted to advanced materials such as PEEK polymers and braided carbon fibres. The rivet setting operation, taking advantage of the deformability of bi-axial braids, will relax the drilling precision requirements. The composite rivet will be of similar material to the surrounding composite structure, eliminating the galvanic corrosion issues. Also, the composite rivet's low electric conductivity will mitigate the risks associated with electrostatic discharge when using metallic fasteners. A robotized riveting machine will be designed in order to study and determine the optimal riveting parameters. Mechanical performance of simple joint configurations will be characterized. Meeting these objectives will allow us to develop a new technology that has the potential to reduce cost associated with drilling and assembly, improve the safety, lower the weight of the aircraft.