Coupled thermo-mechanical simulations of shot impacts: Effects of the temperature on the residual stress field due to shot-peening

Shot-peening is an industrial surface treatment used to improve fatigue life of mechanical components. This process generates a compressive residual stress field on the part's surface and offers a protection against crack initiation and propagation, corrosion, etc. Although the consequences of the process on fatigue life are well known, the physical influence of the relevant parameters is not fully understood. Few of the existing shot-peening models are thus able to reproduce the correct residual stress field obtained via the actual process. This paper presents a finite element simulation of an impact including thermo-mechanical effects to investigate the influence of temperature on the residual stress field obtained through shot-peening. The influence of parameters of the process such as velocity, radius and hardness of the shot has also been studied in relation with thermal effects. it is observed that the temperature can reach 200 degrees C in the material. Further, the temperature significantly affects the residual stress field for high shot velocities. It can be concluded that shot-peening is a complex combination of physical processes, including thermal effects, which should be taken into account to better master this manufacturing process. (C) 2008 Elsevier B.V All rights reserved.