Seismic damage behaviors of structural steels under different constitutive and damage models

Previous studies have established a variety of cumulative damage models (CDMs) for either structural materials or members to perform an exquisite evaluation on plastic-induced deterioration of structural engineering under severe seismic actions. Nevertheless, the existing CDMs consider different influencing factors and hence tend to produce significantly different simulation performance. On the other hand, the influencing variables of CDMs are likely affected by the description on the cyclic stress-strain relation. Thus, the quantification of seismic damage is affected by the selection of both CDM and constitutive model. Existing relative studies mainly focus on the development and refinement of theoretical models. However, the understanding on simulation performance difference induced by the selection of models is still limited. This paper is aiming to clarify the influence of different constitutive models and CDMs on the cumulative damage behaviors simulated. Firstly, three types of cyclic constitutive models and nine CDMs are reviewed and their material parameters are summarized. The CDMs selected include the deformation-type models, the energy-type models and the combined-type models. Based upon different CDMs, the low-cycle fatigue (LCF) curves of mild structural steel are generated and compared to the corresponding Coffin-Manson relations. Subsequently, the damage evolutionary curves of different CDMs are simulated based upon several representative cyclic loading protocols. The influence of constitutive models and CDMs on the LCF curves and damage evolutionary curves are thoroughly studied. Be-sides, the sensitivity of CDMs on strain ratios and the influence of cyclic loading protocols on damage evolu-tionary curves are simultaneously clarified. The research findings can lay a solid foundation for the selection and combination of the relative analytical models with regards to different circumstances.