Distortion And Local Buckling Analysis On Cold-formed Thin-walled Stiffening Lipped Angle Steel Elements Under Axial Compression

Cold-formed steel has various cross-sectional forms. Due to the thin wall and thin section, It has a high stability bearing capacity and good economic benefit when used as axial compression member. As one of the important section form, cold-formed thin-walled steel is widely used in the Tower, Latticed Columns, Truss Structures, Support Structures and other structures[1]. Opening cold-formed thin-walled steel elements may develop several buckling modes. They are local buckling of plate, Full section distortion buckling, overall buckling[2] and correlation buckling between these buckling modes. Because of the thin wall and limb width of cold-formed angle steel, the local buckling of the members can be improved by setting the intermediate stiffening and the edge stiffening. However, the cross section will becomes more complex and more prone to distortion. When the local buckling limit load is close to the local buckling limit load, there may appear distortion and local buckling, thereby reducing the bearing capacity of the component by a certain measure. Therefore,the correlation between plate groups should be considered in the process of the cold-formed thin-walled lipped angle steel elements’ buckling analysis. No relevant provisions has been list in China’s current specifications for cold-formed thin-walled lipped angle steel elements’ distortion and local buckling is not the relevant provisions.In order to analysis the distortion and local buckling behavior of cold-formed thin-walled lipped angle steel elements under axial stress, this article has carried on the following research:(1) Comparing research method’s scope and characteristics of research method of the cold-formed steel, Then, for stiffening member, we use the method which has considering the associated buckling order named local-distortion associated buckling strength calculation method (NLD) and distortion-local buckling strength calculation method (NDL), finite element numerical analysis methods has also be used.(2) The ANSYS finite element model is established and analyzed, Then the finite element results are compared with the calculation results. Results show that the they are in good agreement.(3) Considering the initial geometry defect effect. Then, analysising the interactive buckling of cold-formed thin-walled lipped angle steel elements under axial stress,when in different stiffener size, different edge width, different plate thickness and different length. Then achieve the effect of each parameter on buckling mode and ultimate load under the interaction of distortion-local buckling. Then offering an appropriate section size range according to the parameter analysis results and the influence of different associated buckling order on the ultimate load of the members.