Influencing Factors Of In-plane Bending Bearing Capacity Of T-Type CHS Joints

Steel tubular structure is widely used in the world because of its beautiful appearance, light weight, simple processing, and quick installation. Especially in recent ten years, the total amount of China’s steel production increased year by year, and circular steel tube processing technology becomes more mature, so steel structure used in China increasingly widespread. Many Chinese and foreign scholars have done a lot of studys on the tubular joints in tensile, compressive strength, and the study results have been relatively mature, at the same time, our country has introduced some corresponding specification. But The node stress is often come from one single reason, also the flexural capacity of node plane can not be ignored in the design of node stess. Our country is lack of corresponding provisions in this regard, and residual stress formed during the cooling process is a valuable reason on the influence factors of the capacity of node circular steel tube, because the common connection mode is by direct welding methods or welding residual heating. Because previous research in this area is relatively rare, so this paper uses AN SYS the finite element analysis software, to study the directly welded tubular flexural bearing capacity of round of nodes of type T, and get the related factors affecting the flexural capacity of nodes, and proposed my own opinion on the existing standard at home and abroad.The main contents of this paper:(1) This artical briefly introduces the development of tubular joints, describes several common node type, and summarizes the present research on directly welded tubular joints.(2) It establishes the three-dimensional model of circular T joints, and considers the characteristics of change of material properties with temperature. Using excessive grid, combines the element birth and death technology, it gets the changing law of temperature field of welding process variation with time.(3) It analyzes the cooled temperature field and stress field, to obtain the regularities of distribution and development trend of the temperature and stress in different places. It also studies the effect of geometric parameters change on the residual stress.(4) It use finite element analysis to study the previous test, and compared with the test results with finite element calculation results, in this way verified the feasibility analysis of the flexural strength of the connection in the operation process by using the ANSYS finite element software.(5) Add static load on54models (considering the residual stress and without considering the residual stress), also using the displacement controlled loading mode, it gets the very moment rotation curve under different parameters. Through comparison and analysis, it gets the influence of residual stress on the bearing capacity of the node degree, and the changing trend of the node bending performance under different parameter.(6) The results of the54models after treated are compared with CIDECT standard values, so to put forward the influence coefficient of specification, and point out problems that need further study.