Study On Welding Residual Stresses In Steel Bridge Decks Stiffened With U-Shaped Ribs

U-shaped rib stiffening orthotropic steel bridge deck is widely used in the bridge deck structure of modern steel bridges due to its superior performance.As the service time of the bridge continues to increase,under the repeated action of the wheel load,the steel bridge deck is prone to fatigue problems.Among them,the joint weld between the steel bridge deck and the U-shaped rib is one of the most prone to fatigue cracking,and the development of cracks will have a serious impact on the usability and safety of the structure.U-shaped ribs and steel bridge decks are connected by welding,the welding process creates complex residual stress fields,it is important to study the distribution and value of the structure to evaluate the life of the structure.The promotion and application of the U-shaped ribs internal welding technology has changed the eccentric stress state of the U-rib web from the structure,improved the fatigue resistance of the steel bridge deck,and also produced a more complex residual stress field.Based on ANSYS,the value and distribution of residual stress field of U-shaped ribs single side welding and double side welding are studied.The blind hole method is used to verify the test.Several common parameters affecting the distribution of welding residual stress field are analyzed,Provide a reference for the optimization of the welding process.The main work of the research is as follows:(1)The U-shaped rib stiffening orthotropic steel bridge deck and its fatigue problems are introduced.The definition,generation and influence of welding residual stress are discussed.The research status of welding residual stress at home and abroad is summarized,and the shortcomings are put forward.(2)The finite element analysis method of welding process and the thermal-elastic-plastic finite element theory of welding are briefly described.The basic theory of welding temperature field and stress field are summarized respectively.The equilibrium equation of stress field is listed and the solution method is introduced.(3)The APDL subroutine was programmed based on ANSYS finite element software to simulate the welding process,and the finite element model of U-shaped ribs single side welding and double-side welding was established.The distribution characteristics of welding temperature field and stress field of U-shaped ribs double-side welding are analyzed,and the stress field results of single-side welding and double-side welding are compared by path operation.(4)The blind hole method was used to perform the test of the same size model,and the test value was compared with the numerical simulation result,verify the feasibility of the simulation method.(5)The effects of deck thickness,opening angle and penetration rate on the value and distribution of welding residual stress field are analyzed by numerical simulation method,which provides a reference for the optimal design of the structure.