Simulation of earing in textured aluminum sheets

In this paper we investigate the phenomenon of earing, which is a troublesome defect often observed during the deep drawing of rolled aluminum sheets. A special finite element analysis for this problem has been developed where only the flange area of the sheet is modelled. A polycrystal and a phenomenological model are used for the numerical simulations of earing. For the polycrystal model, the material behaviour is described using crystal plasticity theory where each material point in the sheet is considered to be a polycrystalline aggregate of a very large number of FCC grains. The Taylor theory of crystal plasticity is assumed. This analysis accounts for initial sheet textures, as well as texture evolution during large plastic deformations. The numerical analysis incorporates certain parallel computing features. For the phenomenological model, a six component yield function proposed by Barlat et al. (Barlat, F., Lege, D.J., Brem, J.C., 1991b. A six-component yield function for anistropic materials. Int. J. Plast. 7, 693–712.) is used. The numerical simulation of earing has been carried out for two textures typical of rolled aluminum sheets. The effects of these textures are discussed, and comparisons are made with experimental data.