Residual stress states after piezo peening treatment at cryogenic and elevated temperatures predicted by FEM using suitable material models

Piezo peening is a recently developed mechanical surface treatment and belongs to machine hammer peening technologies. It has proven suitable to generate a wide range of compressive residual stress profiles and penetration depths depending on the parameters chosen for the process. By this means, greatly enhanced fatigue behavior could be achieved. In this study, the residual stress states after modified piezo peening treatments were determined experimentally and by 3D finite element (FE) simulation. Low alloy steel AISI 4140 was treated at ambient, cryogenic and elevated temperatures. Residual stresses were determined experimentally using the sin²(ψ) method combined with subsequent electrolytic surface layer removal. The FE simulation makes use of a material model, which is capable of describing strain-rate and temperature dependent material behavior as well as the Bauschinger effect and allows for the emulation of surface layer removal for proper residual stress determination. Thus, the applicability of appropriate material modeling to predict experimentally determined residual stress profiles could be demonstrated. (author)