Measurement and modelling of strain-path dependent anisotropic hardening behaviors of high strength steels subjected to pre-strains

Anisotropic yielding and hardening behaviors are important parts of a constitutive model for material formability and strength assessment. In this work, the work hardening characteristics of a high strength steel sheet after it was subjected to 2% and 5% plastic strain in rolling and transverse directions were investigated by both the experimental measurement and mathematical modelling. It was observed that the material with the mild initial anisotropy showed a strong anisotropic work hardening effect after strain path was changed. A material model was proposed by Ma and Aung in order to reproduce the observed hardening phenomena under various conditions of strain path change. The proposed formulation has a simple form mathematically derived from a modified Swift law which can be easily implemented into existing FEM software as a user material model. This anisotropic hardening model for plane-stress condition was combined with Hill48 yield function and associative flow rule for numerical simulations. The model was validated through comparing the simulation results with experimentally measured stress-strain curves.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

In this study, the work hardening characteristics of a high strength steel sheet were investigated after undergoing plastic strain in rolling and transverse directions. It was found that a material with mild initial anisotropy showed strong anisotropic work hardening effect after strain path change. A mathematical model was proposed to reproduce the observed hardening phenomena, which can be easily implemented into existing FEM software. The model was validated through comparing simulation results with experimental measurements.