Predictions of forming limit diagrams using a rate-dependent polycrystal self-consistent plasticity model

J.W. SIGNORELLI; M.A. BERTINETTI; P.A. TURNER

INTERNATIONAL JOURNAL OF PLASTICITY

Elsevier B.V.

Año: 2009 p. 1 - 25

0749-6419

In the sheet-metal forming industry, forming-limit strains have been a useful tool for quantifying metals formability. However, the experimental measurement of these strains is a di.cult, time consuming and expensive process. It would be useful if strains calculated with a theoretical model could replace many of the experimental measurements. In this research, we analyze forming-limit strains of metals using a rate-dependent plasticity, polycrystal, self-consistent (VPSC) model in conjunction with the Marciniak–Kuczynski (M–K) approach. Previous researchers have studied forming limit diagrams (FLDs) based on the full-constraints Taylor model. This is the .rst time, to the authors’knowledge, that the self-consistent approach has been introduced to simulate the polycrystal FLD behavior. Numerous microstructural factors characterizing the material have a strong in.uence on the FLD, so our model includes the e.ects of slip hardening, strain-rate sensitivity, anisotropy and initial texture. Finally, the calculation of the FLD with a more realistic scale transition success-fully predicts some of the experimental tendencies that the Taylor model cannot reproduce for alu-minum alloys AA6116-T4 and AA5182-O.