Influence Of Residual Stress To Ultimate Bearing Capacity Of T-shape Section Column

Welding connection is widely used in steel structure. The welding process is a multi-field coupling problem with highly nonlinear, and will cause great residual stress and deformation in the interior of structure, which is related to engineering quality, structure stability, and mechanical properties of the joint. Study on the residual stresses of T-joint is rare because of its complexity. Using ANSYS finite element software, temperature field of welding process and residual stress of T-joint were analyzed. Dynamic simulation of moving the welding heat source and filling welding material step by step were realized by using the"birth and death"element technique. The results show that longitudinal and transverse residual stress is tensile stress in the welds and heat affected zone,and the numeric value of longitudinal residual stress is higher than transverse residual stress. In the web,longitudinal residual stress is tensile stress near the weld,the remaining part is compressive stress, the peak value of the tensile stress is located in the weld zone, tensile stress is higher than compressive stress.Stability is the prominent problems of the steel structures.due to the instability of the structure or components is comparative suddenly,once buckling occures,then the structure collapse,and the residual stress is an important factor of buckling loads.in the paper,T-section column is the research object,reseach on residual stress to the influence of its ultimate capacity.Using ANSYS software,the temperature field and residual stress of the T-section of a certain length is simulated,the residual stressof middle section is analyzed,extracting its residual stress files,the initial stress prepared by an external program is applied directly to the T-section column,in considering the initial defects, the ultimate capacity of the T-section column is analyzed.The results show that:because the presence of residual stress makes the part of compression of the column entry early elastic-plastic state,reducing the buckling load of component,the residual stress significant influences on the stability of compression component,when using finite element method calculate the instability, the residual stress should be considered.