SEM-EBSD based Realistic Modeling and Crystallographic Homogenization FE Analyses of LDH Formability Tests.

Homogenization algorithm is introduced to the elastic/crystalline viscoplastic finite element (FE) procedure to develop multi-scale analysis code to predict the formability of sheet metal in macro scale, and simultaneously the crystal texture and hardening evolutions in micro scale. The isotropic and kinematical hardening lows are employed in the crystalline plasticity constitutive equation. For the multi-scale structure, two scales are considered. One is a microscopic polycrystal structure and the other a macroscopic elastic plastic continuum. We measure crystal morphologies by using the scanning electron microscope (SEM) with electron back scattered diffraction (EBSD), and define a three dimensional representative volume element (RVE) of micro ploycrystal structure, which satisfy the periodicity condition of crystal orientation distribution. Since nonlinear multi-scale FE analysis requires large computation time, development of parallel computing technique is needed. To realize the parallel analysis on PC cluster system, the dynamic explicit FE formulations are employed. Applying the domain partitioning technique to FE mesh of macro continuum, homogenized stresses based on micro crystal structures are computed in parallel without solving simultaneous linear equation. The parallel FEM code is applied to simulate the limit dome height (LDH) test problem and hemispherical cup deep drawing problem of aluminum alloy AL6022, mild steel DQSK, high strength steel HSLA, and dual phase steel DP600 sheet metals. The localized distribution of thickness strain and the texture evolution are obtained. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]