Lubricated Elasto-Plastic Contact Model for Metal Forming Processes

Numerical method for calculating lubricated contact pressures, friction and heat transfer during the metal forming simulations is presented in this study. Parameters of contact between metal forming tool (e.g. roller) and workpiece (e.g. wire, sheet) are important factors in metal forming processes since non-optimal frictional effects can result in lower productivity of process machinery, and in unacceptable shape and surface quality of the products. In order to control friction and heat transfer during the metal forming processes lubricant is applied between the tool and workpiece surfaces in contact. Tool and workpiece surfaces, seemingly smooth, have a large number of micro-asperities which play a significant role in frictional contact effects, thus capturing interaction between the asperities, i.e. surface roughness, and lubricant flow inside surface contact is required in order to have a good representation of contact phenomena. Two elasto-plastic rough surface contact models are implemented in statistical and quasi-deterministic forms. Results of compressible and incompressible forms of modified Reynolds equations are compared. The contact models are implemented as a solid contact boundary condition for a large strain hyperelastoplastic deformation solver developed by Cardiff et al. (2017) in foam-extend. The models will be tested on wire rolling and drawing cases, comparing the results to the contact model developed by Cardiff et al. (2012) based on the penalty method and constant Coulomb friction coefficient.