Residual stress formation during the roller straightening of railway rails

Residual stresses in rails due to roller straightening have become increasi ngly important since they are going to become part of rail purchase specifi cations. Both experimental and numerical investigations have been carried o ut in the past to reveal the formation of, primarily, the dominant longitud inal residual stresses. Most experimental evaluations show a typical C-shap ed stress distribution in the rail cross section where the numerical studie s do not provide a clear picture. A new and more realistic numerical simula tion for the roller straightening process of rails will be presented. The m odel also considers the longitudinal movement of the rail through the strai ghtener. Chaboche's multiple component non-linear kinematic hardening model has been used to account for the plastic behavior of rail steel. The resul ts are in good agreement with the experimental investigations. (C) 2001 Els evier Science Ltd. All rights reserved.