Braided thermoplastic composite rivets for composite structures

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..