Development of Non-Metallic Fastener Designs for Advanced Technology Structural Applications 2004-01-2821

Fastening metallic structure for aerospace applications is relatively straightforward and has been done for some time. Dealing with advanced composites, though, requires a significantly different technological approach, especially primary structure. Although composite material utilization has increased enormously in civil and military aircraft in recent years, the application of composite materials to primary aircraft structure has not kept pace and is still greeted with some skepticism in the aerospace community. In particular, no major transport manufacturer has yet employed composite components for fuselage or wing primary structure. This appears to be changing rather rapidly with the introduction and the evolution of new airframes such as the 7E7 and Blended Wing Body (BWB) concepts.

This paper presents recent developments in the design, fabrication, and testing of composite fasteners and, in particular, solid rivets and hybrid blind fastener assemblies, for use in the mechanical joining of composite and composite/metallic aircraft structural assemblies. It identifies major reasons for the general reluctance of airframers to take advantage of the durability and weight-savings afforded by composites, such as joint integrity, repairability, and maintainability, and addresses how these issues are related to the structural mechanical joining considerations.