Research On The Constitutive Model Of Steel Beam-To-Column T-Sub Connections

T-stub beam-column connections are usually connecting beam and column by setting two T steel components on the upper and lower flanges of the beams, and linking them with high-strength bolts. It belongs to typical semi-rigid connections and presents obviously nonlinearity features on the mechanical property which significantly affects the overall mechanical performance of the steel-frame structure. The current research on mathematical models of the constitutive relation of the T-stub connections is rare, and the instructional basis of structure design is lacking.On the base of experimental data and finite element numerical simulation which under static load and low cyclic loading, the mechanical performance of typical T-stub beam-column connections was taken as the main research object of this paper. And the research focus on the mechanical properties of the node curves which is about the bending moment M and beam-column relative rotation θr, determining the key mechanical parameters such as shape coefficient n, initial stiffness Rki, yield moment Ms, ultimate moment Mu and corresponding rotation θru. According to the mechanical parameters depending on the connection structure, the mathematic model of constitutive relation of the T-stub beam-column connections is constructed, including the linear model, power function model, B Spline function mode, exponential function model and so on, providing simple and practical functions of constitutive model of the connections for the whole structure analysis. Based on the theoretical analysis of the initial elastic state and failure limit state of the connections, the calculation method of Initial Stiffness Rki and Ultimate Moment Mu is given and the failure modes of the connections can be predicted. Three methods are provided to obtain the mechanical parameters of the connections in this paper connetions model loading test, finite element numerical simulation and theoretical analysis. The mathematics constitutive model of the beam-column connections is constructed with the parameters above, suits the integral analysis of steel-frame structure with T-stub beam-column connections.The research results have guidance significance on the application of T-stub connections and further improving the engineering design and analysis theory of the steel structures.