Modelling of Bauschinger effect by various constitutive relations derived from thermodynamical formulation

Bauschinger effect in an AISI 316L austenitic stainless steel at room temperature was studied as a function of the plastic prestrain. Typical uni-axial Bauschinger tests in tension-compression and in compression-tension were carried out. Internal and effective stresses were evaluated from the experimental stress-strain curves using the method proposed by Kuhlmann-Wilsdorf and Laird. Four constitutive relations derived from a thermodynamical formulation were identified using an inverse identification method. The modelled stress-strain curves were then compared to the experimental ones. Bauschinger effect was characterised using Bauschinger indicators proposed in the literature in terms of strain, stress and energy, respectively. These indicators were evaluated from the experimental stress-strain curves on the one hand, from the modelled ones on the other hand. Their variations as functions of prestrain were then compared. The best constitutive relation uses two non-linear kinematic work-hardening terms.