| For composite beam bridges with corrugated steel webs,corrugated steel webs are used to replace the original concrete webs,which effectively solves the problem of web cracking and reduces the dead weight of the bridge superstructure.However,due to the limitation of processing equipment,transportation conditions,construction and installation,etc.,the width of the corrugated steel web is limited,and the commonly used corrugated steel web is 1600 type.In engineering,the corrugated steel webs are usually connected by welding.Although this connection method has the advantages of good connectivity and integrity,it also leads to the generation of welding residual stress.The existence of welding residual stress will adversely affect the structure,so measuring and analyzing the distribution of welding residual stress is of great significance to ensure the safety of the structure.In this paper,firstly,the accuracy of ultrasonic method to detect welding residual stress was studied,and then ultrasonic method was used to measure welding residual stress of corrugated steel web.Finally,numerical simulation was used to analyze the influence of welding pass number on welding residual stress of corrugated steel web,and the welding process optimization was completed.The main work and results of this paper are as follows:(1)Welded flat specimens with two thicknesses of 16 mm and 24 mm were designed and fabricated,and the residual stress of the welded flat specimens was measured by ultrasonic method and blind hole method,respectively.The accuracy of the stress detection by ultrasonic method is verified by comparative analysis of the detection results of the two methods.The results show that for the path parallel to the direction of the weld,the longitudinal stress is tensile stress at both ends of the path,and the distribution of compressive stress in the middle region is the compressive stress at both ends of the path and tensile stress in the middle region.The residual stress trends measured by the ultrasonic method and the blind hole method are basically the same,and the values are close.(2)The ultrasonic method was used to test the residual stress of the lap welds of corrugated steel webs with two thicknesses of 16 mm and 20 mm in the supporting project.The influence of the thickness of the steel plate on the welding residual stress was investigated.The results show that for the longitudinal stress parallel to the weld direction,the two ends of the path are compressive stress and the middle region is tensile stress;the transverse stress is compressive stress in the middle region and tensile stress at both ends.With the increase of corrugated steel web thickness,the longitudinal stress in the stable path area also increases,while the transverse stress decreases to a certain extent.(3)The finite element software ABAQUS was used to establish the lap welding model of corrugated steel webs with thickness of 16 mm and 20 mm,and the threedimensional thermo-elasto-plastic finite element analysis was carried out,and the welding temperature field and stress field were numerically simulated by the sequential coupling method.The accuracy of the numerical model was verified by comparing the numerical calculation results with the ultrasonic measurement results.The results show that the numerical simulation results are in good agreement with the ultrasonic measurement results of the stress distribution trend,and they are numerically close.(4)The finite element model of corrugated steel web with 4 and 6 weld passes was established by ABAQUS,and the influence of the number of weld passes on the welding residual stress of 20 mm thick corrugated steel web was studied.The results show that the stress distribution trends of 4-pass and 6-pass welds are consistent.For a20 mm thick corrugated steel web,the residual stress with 6 passes is generally lower than with 4 passes.In practical engineering,the welding residual stress of corrugated steel web can be reduced by increasing the number of weld passes. |
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