Modeling of Cyclic Plastic Behavior of SN490B Steel Using Hardening Rule With the Memory Surface Concept

In this study, a material constitutive model based on the memory surface concept was proposed to reproduce the cyclic hardening and softening behaviors of SN490B structural steel under constant strain amplitude loading. The model incorporates combined isotropic and kinematic hardening rules, with strain‐amplitude‐dependent formulations introduced for both. The isotropic hardening rule explicitly accounts for both hardening and softening mechanisms, allowing the model to accurately represent the strain‐amplitude‐dependent cyclic hardening and softening behaviors of the tested material. Material parameters were calibrated using results from cyclic loading tests conducted at six strain amplitude levels ranging from 0.25% to 12%. With the calibrated parameters, the proposed model successfully reproduces the stress–strain response of the tested material under constant strain amplitude conditions. Furthermore, material tests with variable strain amplitude histories were conducted to examine the applicability limits of the proposed model. The results demonstrate that the model maintains reasonable accuracy for strain histories in which the strain amplitude does not decrease during loading.