Verification of sheet metal forming simulation of advanced thin plate parts using a first order friction model

There is today a need of better prediction of part geometry regarding industrial products by simulations. There is a need for better prediction of material inflow, stresses and strains and final geometry. One way to solve this could be by using a more advanced friction model. Today a zero order friction model (Coulomb friction) is normally used. By using a friction model of higher order the friction is not constant and can be changed depending on both different input parameters set from start in friction equation such as surface roughness, hardness, dynamic viscosity and numerous parameters that are automatic inputs to the friction equation during the forming process and taken from the actual FEM simulation such as sliding ve-locity and load. In this paper a first order friction model regarding effects and changes when simulating the forming of advanced thin plate parts has been evaluated. The evaluation has been performed in several steps. First an analysis of variance was made to see how different input parameters, and variation of these, affect the output regarding material inflow, formability and calculated friction at a specific position. Of course also the actual setup of the forming simulation influences the output and can be even more important to adjust when using a higher order friction model. Because of this different ways of meshing were evaluated. A final verification has been made in a special demonstrator tool. In this tool it is possible to evaluate the effects in a scientific way and the tool is verified against real part production.