A study to predict failure in biaxially stretched sheets of aluminum alloy 2024-T3

The 2024-T3 aluminum alloy is extensively used for making aircraft parts. This alloy has a relatively low ductility at room temperature, and is generally heat-treated before forming. The present study experimentally and numerically analyzes the formability of AA2024-T3 sheets subjected to biaxial stretching. The aim of this study is to provide an appropriate criterion to accurately predict sheet failure, which will allow for the optimization of the stretching operations, and provide the means to evaluate when heat treatment can be avoided. The fracture process of AA2024-T3 stretched sheets is experimentally analyzed, obtaining the FLD at fracture. A selection of classical ductile failure criteria (integral and local criteria) is implemented in ABAQUS, and their capability to predict sheet failure is studied in detail. It is found that the local criteria, in particular Treca's criterion, provide a better description of the failure process than the integral criteria. Finally, the influence of bending strains in the initiation of failure is also discussed.