Improvement of an iterative and staggered approach for a model of mixed-lubrication in cold rolling

Modelling of cold rolling process is an interesting tool to optimize a mill configuration: diameter and roughness of the cylinders, rolling diagrams, lubricant viscosity... Built from two existing "Wilson" type models for mixed-lubrication of cold rolling, a new model preserves their advantages : sound physical modelling and robust iterative and staggered numerical approach. Two theoretical improvements applied to this model allow a more broad field of applications. The main innovation consists in applying the radial return method, well-know in the field of the finite element method for time integration of the viscoplasticity law, to the slab method. Some numerical results will illustrate both enhancements.