engleski

Algorithmic formulation for evolutionary anisotropic plasticity model for sheet metals

In the present paper elasto-plastic constitutive formulations based on the orthotropic Hill (1948) stress function and distortional evolution of the yield function/plastic potential are presented. The anisotropy parameters of the Hill (1948) yield function/plastic potential are introduced as functions of the equivalent plastic strain. The formulations are developed and analyzed considering experimental data for the selected steel sheet sample with reported significant variation of the instantaneous Lankford parameter with straining. Predictions of the directional dependences and variations with straining of the yield stress ratios and Lankford parameters obtained by the presented description are considered. The algorithmic formulation of the analyzed constitutive description is derived by the application of the implicit return mapping algorithm. In order to estimate accuracy of the developed algorithm iso-error maps are calculated and analyzed.

anisotropy evolution; sheet metals; stress integration; Hill stress function

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