Analysis On Stability Behavior Of Cold-formed Channel Beams With Complex Edge Stiffeners And Holes

At present,cold-formed thin-walled steel has been widely used in the construction industry.In order to facilitate the passage of wire and pipe,save steel and reduce the weight of the structure,it is often necessary to open the hole on the web of the cold-formed thin-walled steel structure,the mechanical properties of the member with holes is affected.Opening holes will reduce the lateral bending stiffness of components,and the confinement of web to flange will also decrease.Eventually,the ultimate bearing capacity of components will decrease,and the buckling mode will also become more complex.Therefore,it is an urgent problem for researchers to study the effect of hole on the stability of the component.At home and abroad,the research on cold-formed thin-walled steel beams without holes has been more mature,but most of the research on the beam with holes is concentrated on the beam of the conventional common curling channel steel section.As the cross-section forms of cold-formed thin-walled steel members become more and more complex,their mechanical properties change accordingly,so it is necessary to further study the perforated components of these sections.Based on the above situation,C-section and ∑-section beam model with different section sizes are established based on the previous experiments in this paper.Under the condition of pure bending and non-pure bending,the influence of the ultimate flexural capacity and buckling mode on the variation of pore parameters is studied by changing the parameters such as the hole width,the height of holes,the shape of holes and the spacing between holes.Finally,referring to the existing direct strength method(DSM)for cold formed thin-walled steel beams with holes and the direct strength method for beams without holes in our country.,proposeing the direct strength method for the cold-formed thin-walled steel beam with complex edge stiffeners and Holes,which is suitable for China’s engineering practice.Under the same conditions,by changing the width,height,shape and distance of the hole,the influence of the change of the above parameters on the buckling mode and the flexural capacity of the perforated component is studied.The results show that the width,shape and spacing of holes have little influence on the buckling mode and flexural capacity of the members.The change of opening height has great influence on the buckling mode and flexural capacity of the perforated beam.With the increase of opening height,the bending bearing capacity of the component is decreased more.In this paper,the bending bearing efficiency of the net section of the component is taken as an index,studying the change trend of flexural bearing capacity with opening rate(hole height and web height ratio).Finally,a reasonable suggestion is given for the hape and size of holes of the component.Finally,combining with the results of finite element analysis and drawing lessons from the existing formulas for calculating the flexural capacity of cold-formed thin-walled steel with holes and domestic existing beams without holes,presenting the direct strength method for calculating the flexural bearing capacity of ∑-section perforated channel beams with complex edge in pure bending state and the flexural bearing capacity of ∑-section and C-section perforated channel beams with complex edge in non-pure bending state.The validity of the formula is verified,which can be used as a reference for practical engineering application and standard revision.