Modelling the cyclic response of structural steel for FEM analyses

Modelling the cyclic response of structural steel plays an important role in the design and performance assessment of steel structures. Up to date, several mathematical models were developed to simulate metal plasticity, but only some of them were implemented in Finite Element Method (FEM) based software packages such as Abaqus, by using incremental plasticity procedures. Within this article, the “built-in” combined isotropic/kinematic hardening model is used to model metal plasticity under cyclic loading regime. A brief description of the constitutive model together with the calibration procedure of the material parameters based on experimental data are presented. Finite element analyseswere carried out on simplified FEM models to provide numerical predictions using the calibrated material parameters. Since the “built-in” combined model has several limitations (especially related to the isotropic component), adjustments of the material parameters were made to accommodate to different loading histories. The chosen material model and the calibrated input parameters are validated byanalysing the FEM predictions to be in good agreement with the experimental results with respect to cyclic behaviour and failure mode.