Braided thermoplastic composite rivets for composite structures

现代飞机结构的很大一部分是用复合材料制造的。这些材料坚硬而坚固，但比传统航空制造中常用的铝、钛或钢等金属材料更轻。复合材料组件必须使用重型钛紧固件组装，因为结构绑定不能得到政府当局的认证。此外，对钻削精度的要求远高于金属结构紧固。本研究项目将开发一种适用于复合材料结构的复合材料铆钉。将使用拉挤制造技术生产铆钉毛坯。拉挤必须适应先进材料，如聚醚醚酮聚合物和编织碳纤维。利用双轴编织的可变形性进行的铆钉定位操作将放宽对钻削精度的要求。复合铆钉将采用与周围复合结构类似的材料，从而消除了电偶腐蚀问题。此外，复合铆钉的低导电性将降低使用金属紧固件时的静电放电风险。为了研究和确定最佳的铆接参数，将设计一台机器人铆接机。简单连接结构的力学性能将被表征。实现这些目标将使我们能够开发一种新技术，这种技术有可能降低与钻探和组装相关的成本，提高安全性，减轻飞机的重量。

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, willrelax 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.