The Impact of Residual Stress Relaxation on Fatigue Life Enhancing Effect of Cold Expansion

Abstract

A numerical analysis was performed, using three-dimensional finite element method to assess the impact of residual stress relaxation on the fatigue strength benefit of cold expansion. Fatigue lives of cold expansion hole made from aluminium alloy 7050-T7451 under different relaxation time are presented, the results reveal that the fatigue life enhancing ratio is inversely proportional to the stress relaxation time, residual stress relaxation can weaken the benefit of cold expansion strongly.