The Study On Stability Performance Of Channel Beams With Complex Edge Stiffeners Under Bending And Shear Condition

In recent years,cross section forms of cold-formed steel are becoming more and more novel.Cold-formed steel of new section form with complex edge is getting more extensive application in the practical engineering.However,under bending-shearing combining condition,research on stability performance and calculating method of complex edge channel steel needs a further study.It is also a subject on interact effect between distortional buckling and the other buckling modes.It influence obviously on component stability and bearing capacity for the existence of complex edge and stiffeners on the web.Nowadays,domestic researches on stability performance and bearing capacity of beam with complex edge under pure bending condition are relatively mature,but unfamiliar under bending-shearing combining condition.What is more,formula for the direct strength method(DSM)of complex edged bending channel with stiffeners on the web under bending-shearing combining condition have not yet been established.Based on current research situation,C-shape channel steel beam with complex edge,channel steel beam with complex edge and V-shaped stiffener on web and channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition were made a research in this paper.Finite element analyses were conducted for the three kinds of section forms.Firstly,influences of web thickness,web height and stiffener height ratio on ultimate bearing capacity,buckling modes and stress distribution of channel steel beam with complex edge were studied.Secondly,bending bearing capacity under bending-shearing combining condition between C-shape channel steel beam with complex edge and channel steel beam with complex edge and V-shaped stiffener on web were made a comparison,provided that with the same section sizes.Finally,the direct strength calculation methods for the bearing capacity of channel steel beam with complex edge and V-shaped stiffener on web and channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition were put forward,based on that of C-shape channel steel beam with complex edge.Research shows that the ultimate bearing capacity decreases with the increase of web height-to-thickness ratio under the same loading condition,but it influences little on buckling modes.The buckling modes of components with web stiffeners were mostly performing distortional buckling and local buckling.Bending bearing capacity between C-shape channel steel beam with complex edge and channel steel beam with complex edge and V-shaped stiffener on web varies little,on condition that with the same component section parameter.The optimal cross section,which bending bearing capacity is the maximum,of channel steel beam with complex edge and ∑-shaped stiffener on web was established in this paper,by varying web beam with complex edge,was also practicable for that of channel steel beam with complex edge and V-shaped stiffener on web,on base of finite element simulation results.What is more,the direct strength method of channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition was suggested in this paper.The applicability of the formula was verified,which could be made a reference on practical engineering application and specification revision.