Influence of process parameters and process set-up on damage evolution during stretch drawing of u-shaped profiles

The damage state in the form of voids and lattice defects of a sheet metal component has a substantial impact on the performance of a component in service regarding fatigue or crash behaviour. Therefore, managing the damage evolution during forming, especially the accumulation and distribution of damage, by targeted changes of the process parameters and set-up enables to improve component performance by influencing the stress-strain state [1]. The evolution of the stress-strain state during the forming process and along the process route represents the most significant factor influencing the resulting damage state. This paper focuses on the influence of the damage state of sheet metal components in order to improve the performance of a component regarding fatigue and crash behavior. Considering a variation of the process parameter (drawing die radius) and change in process set-up (singlestep, multistep, reverse stretch drawing) the damage accumulation and distribution within the component is analyzed using a calibrated LEMAITRE damage model. For the consideration of this paper, an u-shaped geometry of dual phase steel DP800, which is often found as an element in vehicle body construction, is used.