Material Properties of Aluminum Alloy for Accurate Draw-Bend Simulation

Abstract

The main objective of this paper is to simulate springback using a combined kinematic/isotropic hardening model. Material parameters in the hardening model are identified by an inverse method. A three-point bending test is conducted on 6022-T4 aluminum sheet. Punch stroke, punch load, bending strain, and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Material parameters are identified by minimizing the normalized error between two bending moments. A micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plasticity models. ABAQUS/Standard, which has the combined isotropic/kinematic hardening model, is used to simulate draw-bend of 6022-T4 aluminum sheet. Absolute springback angles are predicted very accurately.