Bailuremechanism And Broken Fortification Of H-beam To H-Column Weak Shaft Connection

Steel frame has been widely used in building projects as a kind of new-type structures, whichis safety and credible, economic and applied, energy and land saving, green and environmentalprotection. But earthquake damage investigation showed that the poor anti-seismic capability ofstructure dued to the brittle failure of traditional steel structure joint under the effects of earthquake.At present, the study for steel frame field was mainly concentrated in the column strong axis. Butthe study was very little to the same common column weak axis, which has worse mechanicalperformance and is more difficult for installation.The connection of the sub-procedure mold piece, which compiled the ellipsoidal yield model,was linked by the open interface of ANSYS software. Through the failureanalysis and numericalsimulation of test of H-beam to H-column weak shaft node by the program, the correction factor ofthe ellipsoidal fracture model was calculated for equivalent to considering the effects of weldingresidual stress and welding defects.With ellipsoidal fracture model which considered welding residual stress and welding defectsas the criterion, the failuremechanism was studied about the basic joints (specimen BS) of H-beamto H-column weak shaft connections of steel frames. The result shows that the edge of butt weld inbeam flange has high stress concentration, where the Average stress and the Equivalent stress washigher in the plastic deformation stage. Initial crack appeared in the edge of butt weld, whichrapidly expanded to the core with the loading increasing. The plastic hinge of the conventionalnode reaches about0.015rad, Which far less than the0.03rad, so its ductility is seriouslyinsufficient, and where brittle failure easily happen.With the ellipsoidal fracture model as the criterion, the new-type connection was advised,which used the circular arc connection and bigger cope hole, while with holes on flange and web.On the basis of dissecting the failuremechanism of new-type connections, weakending parameterswere analysised for the influence law of weakened parameters on mechanical behaviors of theconnections, and the proper parameters of connection were suggested to improve the jiontsductility.The results obtained in this paper provide the reference for engineering design and standardrevision, especially for further studing on the beam-column weak shaft link and the overallinfluence of steel frame...