Direct-Friction Riveting of polymer composite laminates for aircraft applications

Abstract

Friction Riveting is an alternative joining technology to the conventional mechanical fastening suitable for woven-reinforced polymer composites. In this paper, the feasibility of Direct-Friction Riveting is demonstrated for Ti6Al4V rivet and carbon-fiber reinforced polyether-ether-ketone laminate single lap joints. Due to high shear rates, elevated process temperatures (500-900°C) and fast cooling rates (38 ± 2°C/s) experienced by the rivet tip, α’-martensitic structures were identified in the rivet anchoring zone along with fiber and polymer entrapment at the rivet-composite interface. An average ultimate lap shear force of 7.4 ± 0.6 kN similar to conventional lock-bolted single lap joints was achieved. These results indicate that Direct-Friction Riveting is a competitive method with potential for improvement and further application in aircraft structures.