Cold expansion is a useful process for im- posing compressive residual stresses around the holes in riveted and bolted connections. These stresses in- crease the fatigue life of holed parts. Distribution and amount of exerted residual stress dependent on vari- ous parameters as material, distance of adjacent holes, hole diameter, cold expansion ratio and plate thick- ness. In this study, experimental and numerical results for two different aluminum alloys and various holes distances are investigated and compared. Effects of mentioned parameters on the residual stress are stud- ied.
