Finite Element Simulation of the Bending and Springback Behavior of Advanced High Strength Steels (DP780)

In this work two bending processes are examined. The first is bending and springback in a V-die. The second is bending and springback in a “small radius” bender machine. Springback for both processes are experimentally measured for a DP780 advanced high strength steel (AHSS). The bending/springback processes are also modeled using finite element analysis (FEA), and the factors examined are; the effect of the element type (2D shell vs. 2D solid), and material model (isotropic hardening vs. kinematic hardening). Analytical models are also used to predict (where possible) bending and residual stresses, as well as springback. Comparisons are made between experiments, analytical models, and FEA in order to gain a better understanding of kinematic hardening effects, as well as the ability of shell/solid elements to predict these effects. In the analysis, planer isotropy is assumed, as well as a constant elastic modulus.