Numerical Simulation Of Welding Residual Stress And Fatigue Analysis In U-rib

At present,the style of the stiffener of the bridge deck is very diverse,the orthotropic plate,which is mainly in the form of U-rib,is widely used in bridge engineering design.Bridge deck and U-ribs are mainly welded joints,under the influence of high temperature in welding heat source,the structure will be obvious plastic deformation.And after welding cooling,structure can't fully recover due to plastic deformation so that residual stress caused by the followed,both on the strength of the structure and stability,fatigue,etc.the existence of the residual stress can cause a lot of adverse effects.Under the joint action of the welding residual stress and the vehicle load on the bridge deck,the impact on structural security is even more significant.In order to minimize the residual stress caused by welding in structure design,this paper takes the Xinghai Bay sea-crossing bridge as the engineering background,and takes the U-rib of the bridge deck as the research object.In ABAQUS finite element software,the local model of the bridge panel U-rib is established,which is to analyze the distribution law of welding residual stress,combined with the Fe-safe,study on the fatigue life change trend of U-rib of bridge deck under the effect of welding residual stress,there are the following aspects of the work:(1)Summary of fatigue calculation of finite element analysis of basic theory about welding residual stress and the bridge panel U-rib,this paper introduced the research of domestic and foreign relevant and achieved certain results.(2)Collecting the thermodynamic properties of materials at different temperatures,loading the double ellipsoid heat source in the form of subroutine Dflux,through numerical analysis,the distribution form of temperature field and stress field after welding simulation of bridge panel U-rib were calculated.The distribution law of residual stress of structure welding is expounded from the three directions of welding seam,plate thickness and perpendicular to the welding seam.(3)The results of welding residual stress obtained by the finite element analysis method of this paper are compared with those of previous experimental data,and to prove the effectiveness of the simulation method in this paper.Then the change of residual stress under different roof plate thickness and different welding groove angle is analyzed.(4)Considering the influence of welding residual stress,the fatigue life of the U-rib under residual stress or without residual stress is calculated and compared.By changing the two geometrical parameters of roof plate thickness and welding groove Angle,which is studying the change trend of minimum structural fatigue life and safety coefficient.This article systematically shows the calculation process and numerical analysis of bridge panel U-rib in welding residual stress and fatigue life,the results of the analysis show that: the maximum residual tensile stress occurred near the welding seam in the roof and the U-rib plate,with the roof plate thickness increasing,the residual tensile stress increasing in the roof and floor U.And with the angle of the bevel increasing,the residual tensile stress decreasing in the roof and floor U.In addition,the existence of residual stress reduces the fatigue life of the bridge deck U-rib,when the thickness of the top plate increases and the welding groove angle is between 45 and 55 degrees,the fatigue performance of the U rib of the bridge deck is the best,which provides some reference for the design of the U rib of the bridge deck in the future.