Analysis Of Mechanical Properties Of KK Type Tubular Nodes Of Spatial Steel Pipe Truss

With the development of architectural forms, the space tube truss structure has beenwidely applied in buildings and structures. The connection of pipe truss structurecommonly adopted tubular nodes type, because the geometrical and material properties ofthe node region is very complex, damage form is varied, there are serious stressconcentration phenomenon, and the factors affecting the ultimate capacity of the nodes arevarious, so the design of the nozzle-vessel junction node is a difficulty of steel structure,the analysis of the static performance of such nodes for many scholars has become animportant research aspect.This paper chooses KK type steel tube truss in, using ANSYS finite element software,the simplified model of node, the boundary conditions are determined, define materialproperties, bar size and mesh density, verified the reliability of finite element modelandexperiment.Define materialproperties, barsize and meshdensity, and experimental verifiedthe reliability of finite element model. By changing the parameters as the research methods,the factors on the bearing capacity of spatial tubular nodes are researched.Comprehensively examines the effect of the main geometric parameters, such asabdominal chord diameter ratio β, chord thickness γ, angle θ between branch and director,abdominal chord thickness ratio τ, overlapping rate Ov, and the axial pressure on space KKclearance and lap round steel pipe node deformation, failure mode and the ultimate bearingcapacity, and analyzes the various causes of the phenomenon.By analyzing the changesof various parameters, the stiffness of chord is greater with the chord diameter thicknessratio increasing and carrying capacity is also higher;abdominal chord diameter is too largethan beta should not be, otherwise it will cause stress concentration, and increase with thebeta increases bearing capacity; overlapping rate capacity Ovto the node influence, it alsoincrease with the increase of Ovvalue; hidden node weld lack, when the overlapping rate isless than60%, not even in the hidden seam welding can meet the bearing capacityrequirements. When the overlapping rate is greater than60%, hidden weld proportion ofrelatively large, so in the high overlap rate, hidden weld must be welded. This paper compares the finite element analysis results and the correspondingformula (10.3.3-6) in steel structure design code (GB50017-2003), points out thedeficiency of the formula, and fits ultimate bearing capacity formula of the KK nodesaccording to the multivariate linear regression technique.