STUDY ON CONSTITUTIVE MODEL OF STRUCTURAL STEEL UNDER CYCLIC LOADING

In the aseismic analysis, the one-dimensional constitutive model of structural steel under cyclic loading is the basis for seismic response analysis in aseismic design. In order to simulate the seismic response more accurately and be able to apply to practical engineering, a uniaxial and simplified constitutive model of structural steel under cyclic loading is proposed in this paper which includes: monotonic loading curve, hysteresis skeleton curve and hysteresis criteria and the model describes the seismic reaction through establishing the mathematical models of structural steel under cyclic loading. According to the model and UMAT provided by the user subroutine interfaces, based on finite element software ABAQUS, a steel uniaxial hysteresis constitutive model is developed for the structural analysis. It is proved correct and applicable of the model proposed in this paper through comparing with the reaction of test data under a variety of loading systems and the accuracy and feasibility of nonlinear time history analysis is ensured for the steel structure system under earthquake. The results show that: the responses of steel under cyclic loading and the monotonic loading are quite different. Therefore, the skeleton curve under cyclic loading plays an important role for accurate numerical simulation; the hysteresis criteria of structural steel under cyclic loading is also very different from the one used in constitutive models of finite element software which has great effect on the accuracy of the aseismic design and calculation.