B. Gurrola, H. R. Zonker, Alcoa, Inc., Alcoa Center, PA; L. Haylock, Alcoa Fastening Systems, Torrance, CA

Summary:

The XPL is a new high-performance, two-piece fastening system that simplifies the assembly for hybrid metallic/carbon fiber reinforced plastic (CFRP)structures. The XPL system builds on proven lockbolt technology to provide high sustained clamp-up and interference fit in metallic structures and high clamp-up with low bearing stress in composite structures. The materials selected for both components combined with available supplemental coatings render the system galvanically compatible to metallic or CFRP. The extended grip range of 0.134” - more than twice the standard 0.0625” makes it suitable to accommodate the wider variation in the thickness of CFRP structures. The system provides favorable specific strength, specific preload and commonality among components to reduce errors and reduce inventory cost.