Journal
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
Volume 34, Issue 11, Pages 908-920Publisher
WILEY-BLACKWELL
DOI: 10.1111/j.1460-2695.2011.01584.x
Keywords
failure mode; friction stir stitch welding; hook geometry; kinked cracks; stress concentration factor; weld strength
Ask authors/readers for more resources
Stitch friction stir spot welding (FSSW) is performed on 6022-T4 Al alloy using a concave shoulder tool with cylindrical pin. Stitch FSSW is an extension of the conventional spot FSW process where an elongated (oval) spot is produced instead of a circular spot. The main advantage of this process is that it gives appreciably higher strength than conventional spot FSW due to an increase in the joint area. In this research, an experimental and numerical approach is taken to understand the failure mechanism of stitch welds made in lap-shear configuration. There are four ways (orientations) in which specimens can be welded to produce a lap-shear specimen - two in transverse direction and two in longitudinal direction. The static strength of welds made with these orientations was found to be different. For stitch welds made in the longitudinal orientation, the failure always occurred near the keyhole at the tool retract position. For welds made in the transverse orientation, failure always occurred in the region of the highest stress. This difference in the weld strength can be attributed to the hook geometry and interface bond strength. The results are explained using a kinked cracked model approach and calculation of stress intensity factor at the hook geometry.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available