Relaxation of Residual Stresses in and around Mechanical Fasteners Due to Fatigue Loading
The residual stresses around clearance-fit mechanical fasteners have been found to be similar to those around cold expanded holes where compressive hoop stresses close to the fastener hole are balanced by far-field tensile stresses. This compressive zone has been shown to prolong fatigue lifetimes around fastener holes. Constant amplitude fatigue loading was applied to single plate rivet specimens for varying numbers of cycles to investigate the redistribution of these stresses after fatiguing. Synchrotron diffraction was used to map the evolution of the residual stresses around the rivets. Little change in the hoop stress local to the rivets occurred until visible fatigue cracks were observed suggesting that relaxation of these stresses is due to the cracks rather than their cause.
W. Reimers and S. Quander
M. E. Fox and P. J. Withers, "Relaxation of Residual Stresses in and around Mechanical Fasteners Due to Fatigue Loading ", Materials Science Forum, Vols. 524-525, pp. 153-158, 2006