A practical constitutive model for AZ31B Mg alloy sheets with unusual stress–strain response

An elasto-plastic constitutive model for evolving asymmetric/anisotropic hardening behavior of AZ31B and ZEK100 magnesium alloy sheets considering monotonic and reverse loading paths

“…Several phenomenological continuum plasticity models have been proposed to capture the hardening behavior of AZ31 under reverse loading paths (Li et al, 2010;Kim et al, 2013;Nguyen et al, 2013). A general approach is to classify the cyclic hardening behavior into three different deformation modes based on the dominant deformation mechanisms such as "Twinning" during in-plane compression, "Untwinning" during reverse tension and "Slip" during tension from the undeformed state or after exhaustion of twinning or untwinning deformations (see Li et al, 2010;Kim et al, 2013).…”

“…ML, RC and RT). This multi-yield surface approach is rather similar to the one employed by Nguyen et al (2013), where multiple isotropic Von Mises yield surfaces were used to model the hardening behavior within different deformation modes (i.e. slip, twinning, untwinning).…”

“…A similar approach was previously used by Nguyen et al (2013), for modelling reverse hardening behavior in AZ31 sheets.…”

“…A rather similar approach was previously proposed by Nguyen et al (2013) where multiple Von Mises yield surfaces were used to model the cyclic hardening behavior of AZ31B Mg sheets. Nguyen et al (2013) suggested that the multi-yield surface approach can be regarded as a special case of the two-surface plasticity modelling approach proposed by Lee et al (2008), where an outer stationary bounding surface and an inner expanding and translating loading surface were used to model the cyclic hardening response of AZ31B Mg sheets.…”

“…The yield surface, at any instant, was defined by two separate yield functions that correspond to the twinning/untwinning and slip dominant deformation modes. Nguyen et al (2013) had proposed a multi-yield surface modelling approach where the hardening behavior of magnesium sheet was divided into three deformation modes (slip, twinning, untwinning). Three separate Von Mises yield surfaces (one corresponding to each deformation mode) along with a set of corresponding hardening equations for each deformation mode, were used to model the cyclic hardening behavior of AZ31B sheets.…”