Failure prediction in the hole-flanging process of aluminium alloys

The objective of this paper is to characterize and predict numerically the limits of the hole-flanging process arising from material failure for two different aluminium sheets. Firstly, an analysis of the types of failure, i.e. necking and cracks, that appear under different process conditions has been performed. Then, a fracture criterion based on local strain measures in tension has been identified for both materials. A particular attention has been paid to the modelling and identification of the constitutive law in a large strain range, and then numerical predictions of the strain limits obtained from successful parts were compared to experimental results. The main conclusions are focused on the occurrence of damage in the conventional hole-flanging process from numerical simulations and experiments, depending on several process parameters.

► Without ironing, damage is localized in the junction radius and at the flanged tip.
► With ironing, damage is localized in the inner core of the flanged edge.
► The die radius has a weak influence on the damage of the flanged edge.
► The influence of anisotropy on the damage distribution is weak.