Bending behavior to fracture of an aluminium alloy involving pre-strain

Abstract

The work associated to this abstract is focused on the modelling of an aluminium alloy under the shape of sheet. It characterizes the mechanical behaviour up to rupture of an AA6016 alloy, taking into account the anisotropy and the hardening of the metal. The mechanical tests on which the model is based on consist of uniaxial tension, simple shear and hydraulic bulging performed at room temperature up to rupture, except for the simple shear. The numerical model is constituted of three parts. The choice of the model is suited for ductile fracture and allows for high flexibility, thanks to a total of 21 material parameters. The material parameter identification is realised through an inverse methodology. The objective of such an approach is to minimize iteratively the gap between the experimental and numerical outputs. Validation of the results is then done with the help of bending tests. The bending tests are performed with and without pre-strain in tension prior to the air-bending. Different amplitudes of pre-strain allows to reach rupture or not in bending, thus giving the possibility to find the value of the parameter controlling the non-linear accumulation of the damage. The correlation between experiments and simulations is proved to be successful and gives a very good representation of the mechanical behaviour of the aluminium alloy studied.