Accelerated 3D FEM computation of the mechanical history of the metal deformation in cold pilgering of tubes

Based on a numerical simulation of a single stroke of cold pilgering of a tube, a post-processing tool has been built, taking advantage of the pseudo-periodic nature of this process. It aims at finding the trajectory of a material point along the ca. 70 strokes it takes to move from the upstream, preform zone to the formed tube area. By cumulating the single-stroke displacements and the rigid body motions (advance and rotation) between the strokes, the successive positions of any material point are computed. Then, the mechanical fields are interpolated, giving the complete mechanical history (stresses and strains). The results show the alternations of tension and compression in all the strain and stress components, typical of the pilgering process—to be used as the input of low-cycle fatigue models.