Study On The Flexural Capacity And Design Method Of Cold-formed Thin-walled Steel With Complex Edge Stiffeners

In recent years,With the rapid development of the building installation industry,the standardization of the building installation market has become more important.Assembled pipeline supports and hangers are widely used in subway tunnels,water conservancy and hydropower,solar power plants,industrial plants,nuclear power plants and utility tunnel engineering due to their fast installation speed,safety and environmental protection.The C type cold-formed thin-walled steel with complex edge stiffeners and the H type cold-formed thin-walled steel with complex edge stiffeners are important components of the assembled pipeline support and hanger,but the cross-section is complex,and there is no systematic study on this kind of cross-section yet.so this paper studies the flexural capacity of such cold-formed thin-walled steel with complex edge stiffeners by two methods of experiment and finite element analysis,and proposes the stress calculation formula of the elastic distortion buckling criticality of cold-formed thinwalled steel with complex edge stiffeners and the yield strength improvement factor ? which considering the influence of the cold bend angle.The experimental research work of 26 specimens in 2 types of tests was completed.The flexural capacity test of C type and H type cold-formed thin-walled steel with complex edge stiffeners with different section forms,wall thickness and specimen length was carried out.The test scheme,test equipment,test phenomena and processing of test data are described in detail.All experiments were numerically simulated using the finite element program ANSYS,and consider geometric nonlinearity,material nonlinearity,and considering the initial geometric imperfections of the specimen.The numerical simulation results are in good agreement with the experimental results,which verifies the correctness of the finite element model.On this basis,through a reasonable simplification of the model,plenty of finite element parameters analysis of the C type and H type cold-formed thin-walled steels with complex edge stiffeners were carried out,including the length of the specimen,the height of the flange,and the spacing of the web holes.mainly analyzed the influence of the hole width and the thickness of the specimen for the flexural capacity and failure mode of the C type and H type cold-formed thin-walled steel with complex edge stiffeners.Based on the existing theory,the formula for calculating the buckling critical stress of the H type cold-formed thin-walled steels with complex edge stiffeners subjected to bending distortion is derived,and the yield strength improvement coefficient ? is given,and compared with the test results to determine the calculation formula for convenient design and use.Using the calculation formula of the stable flexural capacity of the flexural members in the Technical code of Cold-Formed Thin-Wall Steel Structure(GB 50018-2002),the stable flexural capacity of the C type cold-formed thin-walled steel with complex edge stiffeners is obtained,and the theoretical value and the test values were compared.It was found by comparison that the calculation formula given in "Technical code of ColdFormed Thin-Wall Steel Structures"(GB 50018-2002)is still applicable to Calculation of the stable flexural capacity of C type cold-formed thin-walled steel with complex edge stiffeners studied in this paper.