A Multi-scale Friction Model for Sheet Metal Forming Simulations

This paper presents a multi-scale friction model for large-scale forming simulations based on the surface changes on the micro-scale. The surface texture of a material changes when it is subjected to normal loading and stretching. Consequently, the frictional behavior between contacting surfaces, caused by the adhesion and ploughing effect between contacting asperities, will change when the surface texture changes. A friction model has been developed which accounts for the change of the surface texture on the micro-scale. Statistical parameters have been introduced to make a fast and efficient translation from micro to macro modeling. The flattening models are validated by means of FE simulations on micro-scale and the implementation of the advanced macroscopic friction model in FE codes is discussed