Chapter 3: Application of Proposed Hardening Model to Predict Fracture and Improve Press Formability of Door Hinge

To predict a fracture and improve the press formability of a door hinge, the geometric shape of the die and bead punch in the concerned area was improved using finite element simulations and then investigated by experiments. Commercial software (ABAQUS version 6.5, explicit formulation) with a user-defined subroutine (VUMAT) based on a combined isotropic/kinematic hardening model was used for the simulation according to the orthogonal array of Taguchi’s method. As a result, the die corner radius (R) was identified as the important factor for improving the press formability of the door hinge. Improved geometric shapes for the die and bead punch in the concerned area, consisting of a die corner radius (R) of 20 mm, declination of the bead punch (a) of 14 o , and peak angle of the bead punch (b) of 70 o , were also predicted to produce a better reliability compared to the original test sample.