Study On The Stability Capacity Of Cold-formed Thin-walled Steel Column With Complex Edging Unequal-edge Angular Section

In recent years,with the advancement of assembly styles and the requirements for future building assembly rates,light steel modular house of assembled type have been rapidly developed due to their high efficiency,energy saving,and reusability.Light steel modular house of assembled type has been widely used in shops,offices,restaurants,exhibition halls,and construction sites.Scholars at home and abroad have successively carried out research on light steel modular house of assembled type,but the research has mainly focused on the aspects of architectural design,overall structural stress and connection nodes.However,there are few researches on the mechanical performance of the modular building columns.In order to meet the structural requirements,the column in the light steel modular house of assembled type with that of a complex rolled edged unequal angular cross-section and cold-formed through thin-walled steel.The column cross-section is a biaxial asymmetric cross-section,and the cross-sectional form is more complicated.There is also a lack of guidance in the design on the bearing capacity of the column with this section.Therefore,it is extremely important to study the ultimate bearing capacity of cold-rolled thin-walled steel columns with complex crimped and unequal angular cross-sections in light steel modular house of assembled type.The theses is systematically studies the ultimate bearing capacity and failure mode of cold-formed thin-walled steel columns with complex curled unequal-angle angular cross-sections in light steel modular house of assembled type through experimental research,finite element simulation,and theoretical analysis.The contents are as follows:(1)Experimental research on bearing capacity of cold-rolled thin-walled steel members with complex crimped and unequal angular cross-sections.Twelve,divided into three groups with different length,columns were selected,and the axial compression bearing capacity test was performed on four axes of every member section.The entire test content includes material property test,measurement of actualgeometric dimensions of the test piece,initial geometric defect measurement,500 mm short-length column test,1500 mm medium-length column test and 2000 mm long-length column test.The ultimate load capacity of the test piece,the failure mode,load-displacement curve,load-stress curve,etc.(2)The finite element analysis software ABAQUS6.14 was used to numerically analyze the axial bearing capacity of cold-rolled thin-walled with complex curled unequal-angled angular cross-sections.The axial bearing capacity comparison between the finite element simulation results and the test results verified the applicability and accuracy of the finite element model.Then parametric analysis was performed on the cold-rolled thin-walled steel with complex crimped unequal-angled angular cross-sections to investigate the influence for the axial bearing capacity of the column.The parameters includes different length of the column,thickness of the column and different boundary conditions.(3)Aimed at the same cross-sectional area of the cold-formed thin-walled steel with complex crimped unequal angular cross-sections under axial load,five kinds of cross-section members with different limb width ratios were selected for finite element simulation analysis to explore the influence with different length ratio range from 1 to 2 between long limb and short limb on the axial ultimate bearing capacity.(4)The line analysis software CUFSM was used to calculate the critical local elastic buckling load,elastic distortional buckling critical load,and elastic global buckling load for the complex rolled-up unequal-angle angular cross-section with cold-formed thin-walled steel under axial load.Based on the results of finite element numerical simulation analysis,amendments are made to the calculation formula of the axial bearing capacity of the members calculating by the direct strength method to make it more suitable for the design and calculation on the bearing capacity of the column in this section.