Analysis Of Mechanical Properties Of Cold-Bending Thick-Walled Square Steel Tubular Column-H-Beam Frame

As an energy-saving and environmentally-friendly green building,steel structure has the comprehensive advantages of less construction pollution,light weight,good seismic performanee and reusable steel.It i5 more and more widely used in today's increasingly prominent environmental problems.At the same time,people's requirements for the use of steel frame building structures and building space are constantly changing.In the steel structure system,the mechanical properties of the steel frame beam-column joints determine the performance of the entire steel frame structure under earthquake action.In order to solve the problem of brittle fracture damage observed near the welded joints of the column and beam flanges in the earthquake,scholars from different countries have proposed different design schemes.In the previous research results,countries have revised the node domain in the seismic design code.Part of the content.Due to the influence of cold work hardening on the cold-bent thick-walled steel tube,the mechanical properties of the steel material change,and the current design specification does not give the design formula of the bearing capacity suitable for the cold-bending thick-walled square steel tube joint zone.In the current design code,the evaluation formula of the bearing capacity of the box section is related to the shear yield strength of the material and the shear effective volume of the joint zone.However,due to the existence of the corner angle of the square steel tube,the cross-sectional shape is between square and round.Therefore,the existing rectangular panel zone bearing capacity formula is not suitable for direct use.Based on the existing evaluation formula of the shear strength of the panel zone,the correction coefficient cp is introduced to give the cold-rolled thick-walled steel tube bearing.Force calculation formula.The main research contents of this paper are as follows:The finite element software ABAQUS is used to establish the upper ring-type square steel tubular column-H-shaped steel beam steel frame joints.The finite element model is used to verify the reliability of the finite element model.After calculating and changing the flange thickness of the beam,the model is designed in the form of“balanced panel zone design,.In order to make the finite element result closer to the experimental value,the cold work hardening effect of cold-formed thick-walled steel tubular columns is considered in the finite element analysis model.Under the action of reciprocating load,analyze the ratio of the radius of curvature of the cold-formed thick-walled steel tube column to the corner angle D/r,the ratio of the width of the steel tube column to the thickness of the column wall D/t,the width of the steel tube column and the beam height D/h and the axis The effect of pressure ratio n on the bearing capacity,initial stiffness and ductility of the nodal zone;on this basis,the yielding shear bearing capacity of the new upper ring lower-section cold-formed thick-walled square steel tube-H-shaped steel beam joint zone is proposed.The formula for the force formula correction coefficient cp.The results shown that the ratio of the radius of curvature of the thick-walled steel tube column to the comer angle is I/r,the ratio of the width of the steel tube column to the thickness of the column wall D/t,the width of the steel tube column and the beam height D/h and the axial pressxure ratio n.The shear capacity,stiffness,ductility and shear deformation of the joint zone have different degrees of influence;the parameters D/r,D/t and D/h are at the panel zone of the cold-bent thick-walled steel tubular beam-column joints.The influence of the shear capacity correction coefficient ? is large,but the influence of the parameter n on the correction coefficient ? is small.Therefore,the parameter n can be ignored in the evaluation formula;the nonlinear regression analysis of the correction coefficient ? is performed by excel to obtain the finite element analysis.The mean and variance of the ratio of the value to the calculated value are 1.0003,0.0258,respectively,and the confidence interval is 95%.The confidence interval is[0.9497,1.0509].It can be seen that the formula can better evaluate the correction coefficient.?,the calculation formula of the correction coefficient ? of the shear capacity of the cold-bending thick-walled square steel tubular beam-column joint is obtained.