Formability analyses of AA6016-T4 aluminum alloy sheets subjected to roping

Abstract

Due to its good formability characteristics, AA6xxx aluminum alloys have become popular as a light-weight alternative to steel for car bodywork components produced by stamping. In the design of forming operations, numerical simulations are often used, and accurate material models to describe plasticity and forming limits are important to successfully design optimized products and production processes to avoid the reliance on trial and error. For aluminum alloys used in sheet metal forming, the anisotropic plasticity characteristics caused by the directional rolling process has therefore been subject to extensive research over the last decades. A previous experimental program on AA6016-T4 sheets showed that the formability of the material is strongly affected by roping caused by rolling. In this paper, models of anisotropic plasticity, isotropic hardening, instability, and fracture, along with an approach to describe the effects of roping for proportional strain paths are used to predict forming and fracture limits in LS-DYNA.