Direct and Indirect Approaches at the Plasto-Hydrodynamic Lubrication Problem. Application to an Industrial Ironing Process

Abstract

A finite element fluid-structure coupling is developed in order to simulate a lubricated forming process, A dynamic explicit code is used for elasto-plastic deformation calculations and normal and tangential contact conditions are handled using a dynamic projection method. Two complementary approaches to the hydrodynamic lubrication problem are proposed: a classical method using the direct solution of the inverse hydrodynamic problem and an original indirect method based on the so called “optimal control theory.” The applicability of the code developed is proved by the numerical simulation of an industrial ironing process. Results of the two methods are compared in terms of friction forces and film thickness profiles. The distribution of local friction coefficients is also obtained.