| Lattice columns have been widely used in engineering applications,and its stability has always been a key and difficult problem.The research on the stability of the four-limb splicing column under axial compression and bending force can effectively solve the structural safety problem.The purpose of this paper is to establish a spatial calculation model applicable to the four-limb splicing column,explore its stability,and verify the formula of in-plane stability calculation applicable to the four-limb splicing column.This paper mainly accomplished the following research:(1)In this paper,due to the shortcomings of the previous spatial truss model,spatial rigid frame model and hybrid model of beam-bar system,the shell element was selected to establish the finite element model of the spatial thin-walled steel structure.The results of eigenvalue buckling analysis and nonlinear stability analysis of single limb Angle steel model and the four-limb splicing column model were compared and verified.The calculation error of the model is very small,which is suitable for the stability analysis.(2)The calculation formula of the effect of the initial bending on the overall stability of the lattice column was derived.Using the finite element method,the correlation between initial bending of the whole body and initial bending of the four-limb splicing column batching column was analyzed under the condition of complete elasticity and elastic-plasticity.(3)The influence of different residual stress peak coefficient β and different steel yield strength was explored on the ultimate bearing capacity of lattice columns under axial stress of the limb limbs.(4)The development of the formula for calculating in-plane stability in the specification was introduced.In order to solve the problem of whether the section stiffness is zero or the component stiffness is zero,the in-plane stability of the spliced columns was studied.At the same time,the effects of global initial bending,column limb initial bending,residual stress,geometric nonlinearity,and material nonlinearity on the four-limb splicing column were considered,The law of ultimate bearing capacity of the four-limb splicing column was explored under the different section size,different steel strength and different coaxial force and bending moment ratio.The results of the calculation formulas,which are in China’s "Code for Design of Steel Structure"(GB50017-2003)and "Code for Design of Steel Structure"(GB50017-2017),for the inplane stability of the lattice compression-bending member was compared with the calculation results of the stability of the four-limb splicing column in ANSYS under compression and bending,and the recommended formula was proposed for calculating the in-plane stability of the four-limb splicing column. |
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