Application Research And Numerical Simula Tion Of Welding Robot In Arch Rib Weld

At present,the welding of arch ribs of CFST arch bridges in China is generally carried out by manual welding.Under the complicated construction conditions at high altitude,the quality of manual welding cannot be guaranteed,the welding line is uneven,and the percent of pass is low.In view of this,this paper uses all-position welding robot to carry out welding test on thick steel plate and arch rib test steel tube,then checks the appearance of weld seam,and studies the feasibility of automatic welding of arch rib of steel tube arch bridge,The welding parameters of the welding robot are also studied.At the same time,this paper uses ANSYS finite element software to numerically simulate the welding temperature field of thick steel plate,and compare the temperature thermal cycle curves of steel plate test and simulation.The ANSYS finite element software was used to simulate the temperature field and stress field of the rib welding seam.The result shows that:(1)Under a single variable,changing the width of welding gun,welding current,welding voltage,welding speed and the left and right delay of the welding will cause regular changes in the weld width and thickness.(2)All-position welding robot can realize the automatic welding of flat welds and girth welds.(3)By simulating the temperature field of the thick steel plate and the rib ring weld,It finds that the temperature field distribution of the thick steel plate and the rib ring weld is similar: the temperature away from the heat source changes slowly,as the heat source approaches,the joint temperature rises rapidly.The maximum temperature in the welding zone exceeds 2000 ° C.After each layer is welded,the materials enters the cooling stage and the temperature of the entire entity begins to decrease.(4)The temperature thermal cycle curve of the thick steel plate welding of simulation is basically consistent with the test,which proves that the heat source model and material properties used in the simulation process are reasonable,and the calculated temperature field results are accurate.(5)By simulating the stress field of the rib ring welding,the equivalent residual stress of each layer is tensile stress,and the largest equivalent residual stress of the steel pipe appears at the bottom of the inner surface.After the welding,the radial and circumferential residual stresses are compressive stress in most of the inner and outer surfaces;The distribution of axial residual stress varies between the tensile and compressive phases alternatively.During the formation of residual stress,residual stress curves of the radial,hoop,axial and equivalent stress of layers 2?7 are compared with the first layer,,it finds that residual stresses are almost constant except in peaks and troughs.