Realistic finite element analysis model of the pilgering process to deal with initial tube thickness nonuniformity

Traditional finite element analysis (FEA) models for simulating the pilgering process, based on the assumption of a fixed rigid mandrel and uniformity of the initial tube thickness, have practical disadvantages in solving industrial problems due to tube thickness nonuniformity and related mandrel deformation. A novel FEA model of the pilgering process with initial tube nonuniformity is presented herein, using an implicit elasto-thermoviscoplastic finite element method (FEM) with tetrahedral MINI-elements and multi-body treatment scheme, with an emphasis on the moveable and deformable mandrel and practical boundary conditions for the tube material. The effects of the number of layers in the radial direction on the predictions are investigated. The variation in thickness ratio with stroke during the pilgering process is predicted. It has been shown that the pilgering process considerably improves tube eccentricity.