Numerical simulation of residual stress induced by roll-peening

There are various techniques to improve the components resistance against oscillating loads or fatigue. One of the most efficient techniques is to induce a compressive residual stress layer on the surface of the component. This can be accomplished by different methods such as surface coating, shot-peening, heat treatment, laser peening and roll-peening. The latter is widely used for surface modification of flat and cylindrical industrial components such as crankshaft and etc. The distribution, layer thickness, and the maximum of residual stress induced by roll-peening can be influenced by parameters of rolling such as work piece material, radius of roller curved boundary, roller angular velocity, roller transverse speed, and rolling depth. In this work the effect of these parameters are studied by numerical simulations. The material used in this work is AISI 4340. The roller is a solid disk with a curved boundary. The results indicate that: (i) the surface residual stress increases with the increase of rolling depth up to a specific value thereafter begins to decline; (ii) the effect of roller curvature radius on surface residual stress shows exactly the same trend as the rolling depth does; (iii) for a strain rate hardened material which is the case for the material used in this work, the angular velocity of the roller gives rise to the increase of the surface residual stress and finally, (iv) the increase of the transverse speed of the roller brings about the reduction in the residual surface, as expected.