Research On The Structural Performance And Calculation Model Of Q460High Strength Steel Weld Connection

Supported by the improvement research of “Code for design of steel structures”and based on the existing research results available internationally, further experimentalresearch, numerical calculation and theoretical analysis have been carried out to explorestructural performance of high strength steel weld connection. It is found that thestructural performance of high strength steel weld connection is obviously differentfrom that of mild steel, because of the higher yield ratio and lower ductility in highstrength steel. The appropriate design method for high strength steel weld connection isneeded, as the design by linear extrapolation methods cannot meet the requirements ofcurrent construction projects.The paper presented experimental research of4Q460C butt welding tensionspecimens connected with ER55electrode. According to the experiment, the hardnessdistribution, axisal tensile load-carrying properties and constitutive relation of theQ460C butt welding joint were measured. Furthermore,5butt welding tensionspecimens of Q345B in the same dimensions were tested and compared with the resultsof Q460C.In allusion to transverse and longitudinal fillet weld, which are extensively used insteel structure connections,10fillet weld specimens divided into2groups weredesigned. Through the experiment of tension test, the ultimate bearing capacity,ultimate strength and failure mode of the transverse fillet welding lap joint wereobtained. Meanwhile the ultimate bearing capacity, ultimate strength, failure mode anddeformation performance of the longitudial fillet weld were also gained. The stressdistribution of longitudinal weld surface was measured in axisal pure shearing forcewith three-element rectangular rosette. And then, non-linar finite element model oflongitudinal fillet welding lap joint was established with FEA software. According toexperiment result in this paper and other two scholars’ experiment result of26CO₂GMAW welding tests, the finite element model was verified reasonably.Based on the verified finite element model of the longitudinal fillet weld model,the parameter study was set in96different size specimen models with FEA software.The relevant parameters, such as base metal yielding strength f_b,y, base metal ultimatestrength f_b,u, weld metal ultimate strength f_w,u, length of core plate L, thickness of core plate or lap plate t, leg size of fillet weld h_f, tension-shear ratio A_n/A_s, and length of theeffective weld L_wwere changed, and the influence of the changes towards theload-carrying properties was researched by this method.Aiming at the stress distribution nonuniform of the longitudinal fillet long weld inaxial tensile force, this paper used finite element simulation method to calculateshearing stress at the main shearing surface. The nonuniform and regularity of thelongitudinal fillet long weld were analyzed quantitatively. Finally, the load-carryingcapacity reduction method of long weld joint was presented in accordance with currentdesign codes.