Determining plasticity model effects on finite element analysis in sheet metal forming processes

Sheet metals have a wide usage area due to their weight to strength ratios especially in automotive industry. Sheet metal forming processes can be described as complex manufacturing processes for working with thin materials by complex product forms, and die tools are expensive since sheet metal forming processes are in use at mass production. Therefore, sheet metal die tools must be compensate in design stages. Today, finite element analysis (FEA) are in use widely for this purpose. However, prediction performance of FEAs must be accurate. Material models which defines the plastic behavior of the materials effects the accuracy significantly. In this study, the effect of material models on finite element analysis prediction performance was investigated for this purpose deep drawing, square cup drawing, and V-die bending processes were studied using 4 different materials (DP600, DP980, DC05, AA5854). In the study, material models are used as isotropic material-isotropic hardening assumption (Power Law), anisotropic material-isotropic hardening assumption (Hill-48, Barlat-89), and anisotropic material-kinematic hardening assumption (Yoshida-Uemori). Each process was simulated using 4 different material models, than simulation results were compared with experimental studies. The most accurate results were obtained with kinematic hardening material model for all processes.