For mild steel, after significant plastic deformation in one direction, a subsequent deformation in an orthogonal direction shows a typical stress overshoot compared to monotonic deformation. This phenomenon is investigated experimentally and numerically on a DC06 material. Two models that incorporate the observed overshoot are compared. In the Teodosiu-Hu model, pre-strain influences the rate of kinematic hardening by a rather complex set of evolution equations. The shape of the elastic domain is not changed. Another way to describe the observed overshoot is by distortional hardening, like in the model by Levkovitch et al. In this model, a deformation in one direction directly influences the shape of the yield locus, which is apparent even without additional plastic deformation in another direction. Both models can represent the experimental results well, but in the original implementations, the Teodosiu model performs better.\ud
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KEYWORDS: non-proportional loading, plasticity, material model, distortional hardenin
