Thermomechanical analysis of the draw bead test

Abstract

Advanced high strength steels (AHSS) are currently used in stamping processes due to their good strength-to-weight ratio. However, their high strength requires improved knowledge concerning the heat generated by plastic deformation and contact with friction, since this can be an important factor for the accurate simulation of the forming process. The main objective of this study is the thermomechanical simulation of the draw bead test, with particular focus on the temperature rise. In addition to the heat generated by plastic deformation and friction, the finite element model takes into account both the heat losses to the tools and for the environment. The effects of the main process parameters are analysed, in particular, the draw bead penetration, side clearance, the pulling speed of the grip and the coefficient of friction. The results show that the parameter with the largest influence on the blank temperature is the pulling speed of the grip, which dictates the process time and consequently the heat losses by convection and contact. Although the coefficient of friction presents a strong impact on the contact forces, its influence on the temperature is negligible.