Influence of prestrain on the numerical simulation of the roller hemming process

This study focuses on the numerical simulation of roller hemming of an aluminium alloy sample with a curved geometry; this non-planar geometry is obtained by a prestrain procedure similar to deep drawing process. Material characterization was performed through tensile and simple shear tests at different orientations on the sheet plane. The influence of considering the Bauschinger effect, anisotropy, and the strain history on the final geometry was studied. A specific laboratory device for roller hemming was designed to forward an experimental database. The numerical simulation of the roller hemming of these samples is presented here, as well as the correlation between the calculations and the experimental tests, notably the roll-in value and the prediction of wrinkling.