Residual Stress Distribution In Welded T-section Of Q460 High Strength Steel Based On Mechanical Behavior Evolution During Machining Process

In complex,large construction engineering if the use of high strength steel can yield restful revenue and social interest in the engineering.It is indispensable to study the overall stability of high strength steel components,because it can be widely used in construction engineering.Residual stress may be generated during machining and fabrication of high strength steel members.As a significance initial mechanical imperfection,the residual stress affects the overall stability of the components,so it needs to be studied in depth.The distribution of residual stresses in high strength steel with different section forms is studied experimentally and numerically at home and abroad.The main section forms studied are I-section and box-section,but less on the welded T-section.However,this type of cross section has been widely used in the common strength steel structures and will certainly occupy a place in the spreading and applying to steel structure engineering of high strength steel.A comprehensive and in-depth theoretical and experimental study on it can not only provide reference for the relevant design,but also lay the foundation for the formulation of high strength steel design standards.Therefore,the residual stress distribution of the welded T-section of Q460 high strength steel without considering the initial residual stress of steel plate cutting and those with considering the initial residual stress of steel plate cutting are studied by using experimental methods and numerical simulation methods.The influence of sectional geometry of the longitudinal residual stress and the self-balance of the residual stress on each plate is analyzed.The proposed residual stress distribution model considers the influence of the initial residual stress of cutting steel plate.It mainly describes the welded T-section of Q460 high strength steel.The specific research contents and conclusions are as hereunder mentioned:(1)The four welded sections are longitudinal residual stresses in the form of T-sections by plasma cut Q460 high strength steel plates is measured by the sectioning method,which got the trustworthy data support for the follow-on numerical simulation research;(2)Based on ANSYS software,the section welding process is simulated numerically by thermal-structural coupling analysis method.The residual stress along the weld length distribution is studied by using the verified numerical simulation.It is mainly for the welded T-section of Q460 high strength steel without considering the initial residual stress of plate cutting.When the residual stress distribution of the weld length is researched,the affective elements of the section geometry are considered.And the self-balance of the plate is estimated.The results indicate that the tensile residual stress is distinct distributed among two plates meet and the edge of the web,and it does not have any apparent law with the section geometry.The compression residual stress is distinct distributed among the flange extension and the middle part of the web,and it has at evident law with plate width-thickness ratio and plate thickness,showing an inverse relationship.The residual stress of the plate satisfies the cross section self-equilibrium.(3)Based on ANSYS software,the process of steel plate cutting and section welding is simulated numerically by thermal-structural coupling analysis method.The residual stress along the weld length distribution is studied by using the verified numerical simulation.It is mainly for the welded T-section of Q460 high strength steel considering the initial residual stress of plate cutting.When the residual stress distribution of the weld length is researched,the affective elements of the section geometry are considered.And the self-balance of the plate is estimated.The results indicate that the tensile residual stress is distinct generated at two plates meet and the edge of the plate,and it does not have apparent law with plate width-thickness ratio and plate thickness.The compression residual stress is distinct generated in the flange extension and the middle part of the web,and it has at evident law with plate width-thickness ratio and plate thickness,showing an inverse relationship.The residual stress on the plate satisfies the cross section self-equilibrium.(4)A longitudinal residual stresses distribution model is proposed which does not consider the initial stress of steel plate cutting and which considers the initial stress of steel plate cutting respectively.It is mainly for the welded T-section of Q460 high strength steel.The model is coinciding with the experimental results and the numerical simulation results.It can be used in the welded T-section of Q460 high strength steel with different cutting manners,namely shear cutting and plasma cutting.All the conclusions can offer significant data support for the numerical simulation of the overall stable bearing capacity of high strength steel bar,and also provide references for the formulation of design standards for high strength steel,so as facilitating the widespread use of high strength steel in the practical project of steel structures.