A Constitutive Model for Circular Steel Pipe by Spatial Hysteretic Test

Abstract

As a rapid developing structure form in late thirty years, space structures are widely used in all kinds of large-scale public building. However, this structure form usually appears an obvious deformation and serious material plastic under severe earthquakes event. Under this circumstance, the material will be experienced cyclic and accumulated damage which have an important effect on the structural behavior and should be considered in the constitutive model. Tests of thirty circular steel tubes were thus conducted under constant axial and cyclic horizontal loads to derive the rational constitutive model with consideration of material damage accumulation. Further, finite-element model were developed using ABAQUS to simulate tube behavior under load. And then the material damage accumulation was dealt with by a user-defined subroutine encoded with ABAQUS. The parameters in the constitutive model are evaluated by experimental results using the least square method fitting between experimental curve and numerical curve. The comparison between the theory and the experiment with the interface program shows that theoretical curves are in good agreement with experimental curves, which proves not only the constitutive equation is accurate but also the finite element program is applicable for theoretical analysis.