Welding Process And Parameter Study Of Typical Triangular Structure In Single-layer Spherical Reticulated Shell Structure

Welding process is one of most important joining method and GMAW is the most popular approach for various industries.However,the moving heat source is employed for this,causing inevitable distortion and residual stress.The problem can be dealt with an appropriate selection of process parameters.The research object of this research is a main typical triangular structure in single-layer spherical reticulated shell structure.The 3D model of welding components are structured in SolidWorks,and then the 3D model is meshed in Simufact.Mesh.Simulab.At last,the meshed model is analysed in special welding simulation software Simufact.Welding and the distortion and stress can be reached through it.Some welding processes are taken into consideration,namely,sequence,number and position of tack weld,as well as some typical welding parameters like welding speed,welding voltage,welding current,preheating temperature,constraint position,and number of welding robots.Furthermore,some cases are selected to put into experiment with the measurements of angle by universal angle square.The experiments have a good agreement with numerical analysis at the variation tendency.The results illustrate that the distortion and stress is dramatically influenced by the number of tack weld and its odevity;the sequence of tack weld chosen from 3 tack weld shows that the results is best when the middle tack is welded at last;the position of tack is equally essential,and the distortion and stress is much smaller when the tacks are welded at both sides of seam 1and seam2 as well as only the side of seam 2;the influence of welding speed and welding speed have similar results that the variation of stress is more than distortion;when the positions of constraint change from one side to the other,the stress is least serious in the middle;for the cases introducing two robots,both deform and stress are better than the cases using only one robot.Therefore,the parameters are essential for the final results,the cause is the integrated impacts of heat input including the amount,speed and distribution of heat and constraints including type,deactivation time,etc.