Finite element analysis of the effect of coefficient of friction on the drawability

Drawability is a term commonly used to describe the ease with which the metal can be drawn into the cups. The various measures of drawability are limit drawing ratio and the limit strains which are influenced by the parameters like tooling configurations, blank configurations, material properties, and forming conditions. Generally the drawability is limited by tearing of the cup at the punch corners. Friction plays an important role in deciding drawability in such a situation. In this work, the effect of coefficient of friction on limit drawing ratio and the limit strains are studied using an explicit finite element code LSDYNA. The model is validated by comparing force obtained by the existing experimental setup with the one obtained in simulation. The limit strains obtained from the simulation are verified by the analytical equations developed using vortex theory. The results are tallying within 0.17-8.29% error.