Comparison of hysteretic models for steel beams calibrated by means of multi-objective optimisation

Phenomenological models are often used to model post-elastic behaviour of steel members in the framework of concentrated-plasticity approach. Many of them can simulate degradation phenomena occurring during cyclic loading, but are dependent on model parameters without clear physical meaning. To overcome this issue, parameter calibration should be performed by curve fitting of experimental responses. In this work, several numerical models implemented in widely used software packages are calibrated against the results provided by an experimental programme involving cyclic and monotonic tests on open and closed cross-section profiles, according a multi-objective methodology recently developed by the authors. The extensive calibration analyses carried out show that the most reliable model among those investigated is the Sivalselvan-Reinhorn model, which is able to provide accurate simulation of both monotonic and cyclic responses. Extension of the calibration procedure is proposed, with an additional objective related to the envelope curve of the cyclic response, and it is shown that this improvement adds robustness to the results.