Integral Fit Joint Technologies for Composites

Abstract

Seeking to expand the varieties of joining approaches for polymer-matrix composites beyond discrete fasteners as well as adhesive and non-adhesive bonds, novel assembly joints that are integral to the design and fabrication of individual components are presented. Grouped under the title of integral fit joint technologies, prior approaches to eliminating fasteners, avoiding adhesives, or bonding components by ultrasonic or other energy-augmented methods are identified and illustrated. By building upon prior efforts to apply integral fit joints in areas such as snap fits, electronic assemblies, wooden joint structures, and plastic building blocks, potential uses of thesejoining technologies in composites can be identified and evaluated. Application of integral fit joint technologies in composites requires a fundamental understanding of the strengths and weaknesses of composite material systems, component fabrication processes, the forces acting on joints as well as methods for assembling composite components together. A composite snap joint technology developed for high voltage transmission towers serves as an example in demonstrating the potential for using integral fit joints in composite structures.