Research On The Local Buckling Behavior Of Cold-formed Channel Section Steel Based On OIC

In the practical application of steel structure,the carrying capacity of members is often affected by the stability performance.At present,the section classification is most commonly used in most countries in the carrying capacity design of steel structure.Among them,for Ⅰ,Ⅱ class section,plastic hinge rotation ability is good,use plastic design;For Ⅲ class section,namely the buckling occurs,before the material yield using elastic design;The effective width method is used to calculate the carrying capacity of the Ⅳ class section.In cross section classification,different cross section forms with different design methods,this will produce gap between the Ⅱ and Ⅲ class sections.On the other hand,the Ⅳ class section uses the EWM,its calculation is more complicated and not considering the plate group effect.In order to make up for the shortage of EWM,direct strength method for thin and flexible cross sections has been proposed in recent years.As a supplement,continuous strength method for thick section has been proposed in recent years.Although,to some extent,it makes up for the shortage of direct strength method,they are only suitable for the cross section types in their respective ranges,and there is still discontinuity in the process from thick section to thin section.In view of the shortcomings of the existing methods for calculating and designing the carrying capacity,professor Boissonnade proposed the Overall Interaction Concept(OIC)method,which is based on the improved aryton-perry formula,and can be good continuity and consistency in the transition of different sections.Over the years,the research of OIC has been mature in the aspect of closed section members,but further research is needed in the open section members.In this paper,the OIC is used to explore the ultimate carrying capacity of cold-formed channel steel under local stability,and the recommended design formula of carrying capacity under local stability is finally obtained.The main research contents of this paper are as follows:(1)Establish the finite element model of cold-formed channel steel member,compare the calculated results with the collected corresponding experimental data,and verify the correctness of the finite element model.(2)The verified finite element model was used to analyze the parameters of cold-formed channel steel members in the locally stable state,and the key factors affecting the ultimate carrying capacity of cold-formed channel steel were found by considering the influence of the curling length,section thickness,steel grade and height-width ratio of section on the local stability.(3)Based on the results of finite element calculation,the OIC recommended design formula of cold-formed channel steel under axial pressure and pure bending load is put forward,and the results are compared with those of Chinese standard and European code.Finally,the reliability analysis of OIC recommended design formula is carried out.