Residual stress formation during the roller straightening of railway rails

Residual stresses in rails due to roller straightening have become increasingly important since they are going to become part of rail purchase specifications. Both experimental and numerical investigations have been carried out in the past to reveal the formation of, primarily, the dominant longitudinal residual stresses. Most experimental evaluations show a typical C-shaped stress distribution in the rail cross section where the numerical studies do not provide a clear picture. A new and more realistic numerical simulation for the roller straightening process of rails will be presented. The model also considers the longitudinal movement of the rail through the straightener. Chaboche's multiple component non-linear kinematic hardening model has been used to account for the plastic behavior of rail steel. The results are in good agreement with the experimental investigations.