Abstract
Shot peening is a frequently employed process for the surface treatment of gears. It produces an improvement of their mechanical characteristics, and among them of their tooth root bending resistance (also called tooth root strength). In recent years, with the rise and spread of additive manufacturing, the interest in the shot peening of additively manufactured components is growing, with a common example being AlSi10Mg parts produced by selective laser melting. This work aims at assessing the influence of shot peening on the fatigue behavior of AlSi10Mg gears through a finite element analysis and the Findley multiaxial fatigue criterion, which relies on the theory of critical plane. Firstly, shot peening was simulated on a gear geometry through a non-linear dynamic analysis which allowed to define the residual stresses generated by the treatment. Secondly, the Single Tooth Bending Fatigue test was simulated for a wrought (non-peened) case and for a shot peened case. This allowed to find the stress tensors at the nodes of the tooth root, and to determine how they vary during the loading cycle. By elaborating them through the Findley criterion, it was possible to compare the equivalent stresses of the non-peened to the shot peened gears, to quantify the improvement in the tooth root strength produced by shot peening, and to show how local hardening changes the point of crack nucleation on the gear tooth.