Distribution Of Residual Stress In Welded T-section By Q460 High Strength Steel

In recent years,high strength steel(HSS)has been widely used in large-span structures and high-rise buildings.As one of the most important connection methods in steel structure,welding has the advantages of simple construction,material saving and good sealing.However,it also has the disadvantage of welding residual stress and deformation,which leads to brittle fracture and affects its stability.This paper mainly relies on the National Natural Science Foundation Project "Research on the overall stability of Q460 HSS welded T-section compression bar" to analyze and discuss the residual stress of Q460 HSS welded T-section.The corresponding residual stress distribution model is proposed,and then the proposed distribution model is input into the finite element software for self-balancing analysis to verify the accuracy of the proposed model.In terms of material performance test and research,three standard specimens of 8mm and 12 mm thickness were prepared according to the requirements of the specification,and unidirectional tensile test was conducted on them.The elastic modulus,Poisson’s ratio,tensile strength,yield strength,flexural ratio and other mechanical ability-displacement curves and indexes of steel were obtained.The mechanical properties of steel meet the requirements of relevant national specifications.It can be used as a specific parameter in the subsequent residual stress analysis.In the field of section residual stress experimental research,8 welded T-section specimens of 8mm and 12 mm thickness were prepared,4 specimens of each thickness.The residual stress distribution of 8 specimens was measured by sawing method and the holes at both ends of each strip were cold machined by electric drill.Each specimen was cut into strips by Plasma cutting.The width of the split strip is 10 mm.Then a handheld strain gauge was used to measure the change of the spacing between the two ends of the strip.The stress value of each measuring point is calculated based on Hooke’s law.The size and distribution of the residual stress in the section are obtained by synthesizing the stress values of all the measuring points.In terms of the analysis of the influence parameters of the residual stress in thesection and the distribution model,the measured residual stress values of the 8 specimens were integrated.The influence of thickness ratio,flange and web on the residual stress distribution of the T-section of Q460 HSS was analyzed.The results show that the residual compressive stress of the flange and web decreases with the increase of the thickness of the plate and the thickness of the plate,and the relationship between the residual tensile stress and the thickness of the plate is not significant.The residual stresses on the flange and web are self-balancing.Based on the results of parameter analysis,a refined residual stress distribution model for the welded T-section of Q460 HSS was proposed.In the aspect of the finite element verification of the residual stress distribution model of the section,the finite element model is established by using the finite element software ABAQUS.Shell element shell S4 R was selected as model element type.The ideal elastic-plastic model is selected as the constitutive model of the material.The residual stress distribution model is input into the finite element method for the equilibrium solution,which verifies the correctness of the model.The residual stress distribution model proposed in this paper can be used as an initial defect to directly introduce into the study of the overall stability of the subsequent compression bar,and also provide an important reference for the preparation of high-strength steel design rules.