Accurate Parameter Identification for Crystal Plasticity Finite-Element Analysis in a Magnesium Alloy Sheet

摘要

A new procedure of parameter identification for crystal plasticity finite-element analysis in a rolled Magnesium alloy sheet was proposed. The procedure consisted of the following four steps; (1) the parameters for basal slip are estimated to achieve a fit with the initial yield stress under uniaxial tension, (2) a ratio between the parameters for the prismatic slip and the pyramidal-2 slip is estimated to achieve a fit with the evolution of Lankford value, (3) with keeping the ratio, the parameters for the prismatic slip and the pyramidal-2 slip as well as those of basal slip are adjusted to achieve a fit with the stress-strain curve under uniaxial tension, and (4) the parameters for the twinning are estimated to achieve a fit with the stress-strain curve under uniaxial compression. Using the conventional parameters, the evolution of Lankford value was surprisingly larger than that of the experiment although the stress-strain curve was in good agreement with the experimental result. On the other hand, when the newly-identified parameters were used, both the stress-strain curve and the evolution of Lankford value were in good agreement with the experimental results, showing that the proposed procedure gave more accurate parameters.