Prediction of strain distribution and four, six, or eight ears depending on single-crystal orientation using a new single crystal criterion

Abstract

Significant progress has been achieved on modeling the influence of plastic anisotropy on forming of polycrystalline metal sheets. In contrast, the effect of crystal orientation on forming of single-crystal sheets has been largely unexplored. In this paper, using a recently developed single crystal criterion, it is shown that the single-crystal orientation has a very strong influence on forming. Results of F.E. simulations of cup drawing and hole expansion are reported. The same set of values of the anisotropy coefficients, which correspond to Al single crystal (with 5% Cu) is used in all simulations. It is predicted that for the {100}〈001〉 orientation four ears develop whereas for the $$ \left\{111\right\}\left\langle 1\overline{1}0\right\rangle $$ and $$ \left\{122\right\}\left\langle 1\overline{1}0\right\rangle $$ crystal orientations six, and eight ears form. Moreover, correlations between the location of the ears and the variation of the Lankford coefficients in the plane of the respective single-crystal sheets are established. F.E. analysis of hole expansion also show a strong influence of crystal orientation on the distribution of thickness strains and strain localization.