Plane Stress Yield Function for Aluminum Alloy Sheets- Part II: FE Formulation and its Implementation

Abstract

A recently proposed plane stress yield function [Yld2000-2d; Int. J. Plasticity 19 (2003) 1297—part I of this work] that well describes the anisotropic behavior of aluminum alloy sheets was implemented in a finite element code. A short review of the Yld2000-2d relevant features was provided and the complete formulation for the yield function implementation was proposed for its convenient use. Yield surface shapes, yield stress and r-value directionalities predicted with Yld2000-2d for Al–5 wt.% Mg and 6016-T4 alloy sheet samples were compared with those of previously suggested yield functions. Simulations of the cup drawing process for the Al–Mg binary sheet were performed to compute the cup height profiles (earing profiles) with different yield functions. The predicted profiles were compared to experimental data and it was shown that the simulation using Yld2000-2d led to the best agreement between theoretical and experimental results. The drawing and redrawing processes of a circular cup using the NUMISHEET99 (Gelin, J.C., Picart, P., 1999. In: Gelin, J.C., Picart, P. (Eds.), Proceedings of NUMISHEET99, Vol. 2. 13–17 September, Besancon, France) conference geometry and specifications for a 6111-T4 aluminum alloy sheet sample were alsosimulated. The predicted load-punch displacement curves and sheet thickness profiles along different radial directions of the cup were shown to be in excellent agreement with experimental data.