Fracture mechanism of titanium sheet self-piercing riveted joints

Abstract This paper devotes to investigating fracture mechanism of titanium sheet self-piercing riveted joint. Static fracture, fatigue fracture mechanism and fretting behavior of the joints were systematically studied by a Scanning Electron Microscope. The distribution of fretting debris on a rivet surface was tested by an Energy Dispersive X-ray Detector. The results concluded that static fracture pattern of the joints was upper sheet separated with the lower sheet, rivet neck and the button existed a macroscopic crack. Main fatigue fracture pattern of the joints was upper sheet rupture, the crack initiated from the region close to a riveted hole. Fretting wear initiated from the upper sheet surface in width direction and propagated to upper sheet surface in length direction during a continuous fretting process. Fretting wear degree increased with decreasing fatigue load level. Fatigue fracture pattern of the joints was impacted directly by fretting wear severity of contact surfaces.