| The good mechanical properties of the structures with concrete-filled steel tubular flange are in line with the trend of large-span,high-rise,complex,economic and environmentally friendly building structures,and they have good prospects for development.However,the structure with concrete-filled steel tubular flange is different from the traditional open and closed thin-walled sections.It is an open-closed-solid combined section and cannot be calculated directly using the existing stability theory.This makes the problem of torsional buckling and flexural-torsional buckling of the structure with concrete-filled steel tubular flange more complicated.For this reason,the problems of the torsional buckling and flexural-torsional buckling of axial compression columns with concrete-filled steel tubular flange are studied based on the plate-beam theory proposed by Prof.Zhang.The main research content of this article is as follows.(1)Based on the plate-beam theory,the total potential energy expressions of the torsional buckling problems of the four types of biaxially symmetrical axial compression columns with concrete-filled steel tubular flange are deduced,and the corresponding theoretical expressions of warping torsional stiffness,free torsional stiffness and polar gyration radius are given.An energy variational model,a differential equation model,and three common boundary conditions for biaxially symmetrical axial compression columns with concrete-filled steel tubular flange are presented.Based on the differential equation model and the boundary conditions,the critical load formula of the torsional buckling of biaxially symmetrical axial compression columns with concrete-filled steel tubular flange is given.(2)The finite element model of biaxially symmetrical axial compression columns with concrete-filled steel tubular flange is established by using ANSYS,and it was used to verify the correctness of the formula for the critical load of the torsional buckling of biaxially symmetrical axial compression columns with concrete-filled steel tubular flange is verified.(3)Based on the plate-beam theory,the expressions of the centroid and the shear center of the section of uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange are given.The total potential energy expressions of the flexural-torsional buckling problems of the four types of uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange are deduced,and the corresponding theoretical expressions of warping torsional stiffness,free torsional stiffness and polar gyration radius are given.An energy variational model,a differential equation model,and three common boundary conditions for uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange are presented.Based on the differential equation model and the boundary conditions,the critical load formula of the flexural-torsional buckling of uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange is given.(4)The finite element model of uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange is established by using ANSYS,and it was used to verify the correctness of the formula for the critical load of the flexural-torsional buckling of uniaxially symmetrical axial compression columns with concrete-filled steel tubular flange is verified. |
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