Experimental Fatigue Life Quantification of the Effect of Blending Surface Damage on Shot-Peened Aluminum Specimens

This paper presents the results of an experimental test program aimed at the investigation of the effect on fatigue life of blending surface damage on shot-peened parts. The test program was performed on shot-peened aluminum specimens where a surface damage was introduced on the specimen by machining a notch after the shot-peening operation. This notched area was then blended to a smooth surface before performing a four point bending fatigue test. The results showed little detrimental effect of the blending operation and, in some cases, improvement on the fatigue life of the specimen compared to a baseline shot-peened and undamaged specimen. These results were investigated with fractography, residual stress measurement using X-ray diffraction and a Discrete Element Model (DEM) - Finite Element Model (FEM) to simulate the blending and assess the redistribution of the residual stresses in the specimens.