The constitutive equations for FEM analysis

The main aim of this paper is to review briefly different models, from simple to very complicated, for computing the changes in flow stress depending on the deformation conditions. The models are divided into two main groups, each of them characterised by a different set of deformation parameters. Some of the models can be applied to cold forming and some (the more complicated) to hot and warm forming. To be correct, models for hot and warm forming must take into account the history of deformation.