Joining Composite Structures
Publication Date: 2017-Jul-25
The IP.com Prior Art Database
JOINING COMPOSITE STRUCTURES
The invention can be used in differing composite structures whereby fastening is required. It relates to the assembly process of composite structures. It aims to provide a new/alternative way of assembling composite structures e.g wing skins, spars, ribs, stringers etc. Usually fastener holes in metallic aircraft structure are not tapped as this would affect fatigue performance. However, it is a viable concept for composite structures which have excellent fatigue performance. The advantages of this invention include, but are not limited to:
• Single sided, single fastener assembly – reducing overall part count, as well as assembly time and complexity compared to traditional nut and bolt or bolt and insert assemblies.
• Reduced mass by removing the requirement for a nut (when using a bolt). A further mass reduction is possible by using a ‘Grub screw’ type fastener with no head (which incorporates a tooling recess).
• Maintaining Aerodynamic surfaces by partial through thickness holes compared to traditional countersunk fastening, which also have detrimental effects on stress allowables and lightning strike performance.
• Partial through thickness holes also provide the benefit of not requiring sealing (for wing tank, thereby reducing weight and process time), and also still provide a partial load path in the hole location (as the fibres are not broken/cut all the way through the thickness).
The invention decreases assembly time and cost, by eliminating the nut requirement, and relevant processes that are associated with this. The invention can be used in a number of different configurations, such as, but not limited to, tapping a thread in a single component with a clearance hole in the remaining parts (Designs B and C) or in multiple parts (Design A). The advantag...