Two new yield functions for orthotropic sheet metals are proposed. The first one, called Yld2011-18p, provides 18 parameters that may be calibrated to experimental data. The second one, called Yld2011-27p, is a straightforward extension and provides 27 parameters. Both yield functions are unconditionally convex. Their formulations are based on the established concept of multiple linear transformations of the stress deviator. Furthermore, they are able to account for planar as well as for three-dimensional stress states. The proposed yield functions are applied to describe complex plastic anisotropies of different alloys. The ability of accurately predicting earing in cup-drawing is demonstrated by means of a non-linear finite element analysis.

New convex yield functions for orthotropic metal plasticity

Numerical analysis of diffuse and localized necking in orthotropic sheet metals

A simple isotropic-distortional hardening model and its application in elastic-plastic analysis of localized necking in orthotropic sheet metals

A non-associated constitutive model with mixed iso-kinematic hardening for finite element simulation of sheet metal forming

An evolving non-associated Hill48 plasticity model accounting for anisotropic hardening and r-value evolution and its application to forming limit prediction

Holger Aretz

Papers

A consistent plasticity theory of incompressible and hydrostatic pressure sensitive metals – II

A less hypothetical perspective on rate-independent continuum theory of metal plasticity