Simulation of the Cyclic Response of Cold Formed Steel HSS Members by the Ibarra-Krawinkler Model

An accurate evaluation of the seismic response of steel structures under severe seismic events requires a proper simulation of the cyclic response of steel members. In particular, under strong seismic excitations, numerical models should be able to simulate the effect of the cumulative damage caused by plastic local buckling. To this end, one of the strategies used in the literature consists in the introduction, at the end of the beam element, of zero-length rotational springs with cyclic deterioration of stiffness and strength based on the model developed by Ibarra et al. and modified by Lignos and Krawinkler. In the present study, the parameters of the modified Ibarra Krawinkler deterioration model are calibrated against results of refined finite element numerical models on cold formed HSS cantilever elements characterized by different cross-section sizes and different values of the shear length and axial load ratio.