Mechanical Properties Investigation Of The Stiffened T-stub In Tension

Component method is very important method to the moment-rotational relationship of the steel joints.However,due to the unclear mechanical properties and correlation of the mechanical components,the current analysis results can not be applied to practical engineering directly.T-stub is an important component in the applying of component method.It is of great significance to clarify the mechanismof T-stub for the analysis of mechanical properties of steel joints.For decades,a large number of experiments and numerical analysis on T-stub have been carried out by many researchers,the prying force and bending moment of T-stub were deeply discussed,and mechanical model of T-stub was established.However previous studies mainly focused on the internal force of the bolt without stiffener,internal force distribution research of stiffened T-stub are relatively limited.In this paper,the mechanical properties of stiffened T-stub are analyzed deeply by means of experiment and numerical analysis.The specific work is as follows:(1)In this paper,monotonic tensile tests were conducted with 9 specimens,the loading process and failure modes of T-stub were analyzed.The influences of flange thickness,bolt spacing,bolt diameter and stiffener rib on initial stiffness,ultimate bearing capacity and bolt stress of T-connector were studied.The test results show that the failure modes of T-stubs are flange yield and bolt failure.Flange thickness,bolt diameter and stiffener have a great influence on the mechanical properties of T-stub.Increasing flange thickness,bolt diameter or arranging stiffeners can improve the stiffness and bearing capacity of T-stub After the stiffener is arranged,the axial stress and bending stress of bolts are smaller than T-stub without stiffeners,and the proportion of bending stress is lower under the same load case.(2)ABAQUS was used to conduct the parameter analysis,six groups of finite element models were established.The influences of different parameters on the development process of bolt axial force,prying force and bending moment were studied respectively.The finite element results show that compared with T-stub without stiffening ribs,the internal force of the bolts of T-stub with stiffening ribs is mainly affected by the thickness of the flange,the ratio of bolt lateral distance and longitudinal distance.The increase of the thickness of the flange,the ratio of bolt lateral distance and longitudinal distance can reduce the bolt axial force,bending moment and prying force.With the arrangement of stiffeners,the prying force and the bolt bending moment are greatly reduced,but the bolt bending moment can not be ignored.The influence of bolt bending moment on the bearing capacity of bolts should be considered in the practical design.(3)Based on calculation formula of unstiffened T-stub considering prying force and bending moment,the calculation model of the prying force of the ribbed T-stub is proposed and the calculation formula of the bending moment of the ribbed T-stub is revised,and the reliability of the equation is verified.The numerical example shows that the calculated results of the eauation are in good agreement with the finite element results,which has important reference valueto the safety design of T-stub.