Numerical Simulation And Experimental Investigation Of Residual Stress On Weld Beam-to-Column Connection In Steel Moment Resisting Frame

Welding is one of several common steel structure processes,the research of beam-to-column connections(BCC)of steel structure is crucial for the stability of the whole structure,welding residual stress is one of the important indices when evaluating the performance of BCC,so the research about the residual stress of the BCC welding vicinity is the priority among priorities.In this paper,all welded BCC are adopted,and the upper and the lower flange of the beam are provided with two welds,and the beam web has two welds,and there exist a total of 4 welds at the whole BCC.As the welding process is a complex and nonlinear transient thermal process,after the end of the cooling process,the residual stress field will be formed in the weld and near the weld toe.The formation of residual stress is the superposition of various welding factors,whose distributions are not only complex but also a kind of internal self-equilibrium stress.The welding residual stress of BCC subjected to external loads,has a great influence on the fatigue strength,structural stiffness,and stability of BCC,so the research on welding residual stress distributions is one of the important research topic of BCC.In this paper,the distributions of residual stress on BCC are studied.Firstly,the thesis elaborates the research backgrounds and significance and welding temperature field and stress field knowledge theory;secondly,mainly of Q345 B steel plate was under numerical simulation;thirdly,residual stress measurement test on the BCC are detailed;ultimately,simulation of residual stress on BCC is carried out by Ansys software including thermal-structure coupling function section method using indirect coupling namely temperature coupling stress to realize welding temperature for one-way coupled welding stress,which was demonstrated by the corresponding experiment.In the process of numerical simulation of welding residual stress,firstly the finite element BCC model is established employing Ansys APDL language program to complete the forms of heat setting,achieve the loading of moving heat source and use the solder's fill and solidification in the birth & death element dynamic simulation of welding process;finally,the temperature field and residual of BCC welding stress are simulated.The variation law of welding temperature and the distribution of residual stress are obtained by the universal post processing(POST1)and timehist post processing(POST26).This paper established the stochastic thermodynamics model of the whole welding process of the BCC and plate,the simulation of welding temperature field and residual stress.Eventually test results by Little-hole method measuring residual stress of BCC and the simulation results of the residual stress were compared and analyzed,whose results agrees well.