Study On The Stability Behavior Of Cold-formed Thin-walled Rack Columns With Holes

The rack upright used to be perforated cold-formed steel section. Many factors had effects on it's stability behavior. This paper investigates the stability behavior of rack uprights that are commonly used in china by test investigation and finite element parametric analysis. Influences of factors on the failure modes and the ultimate bearing capacity were mainly analyzed including the length of members, the thickness of the plate, the width of additional stiffening lips, the height of stiffening ribs , the hole, etc.A total of 16 specimens that divided into 8 groups tests including 4 groups specimens with two fixed ends and 4 groups specimens with two pined ends had been conducted. The main variable parameters were the length of members, the thickness of the plate. Distortional buckling, interaction between local and distortional buckling, interaction between local and overall buckling, interaction between distortional and overall buckling were observed in the tests. The results showed that the holes and the geometric imperfections had notable effects on ultimate load-carrying capacity of local buckling and distortional buckling respectively.To get the material properties of rack uprights, the material testing was carried out, which established foundation for finite element analysis.All tests were simulated by the finite element program of ANSYS which considered geometric and material non-linearities and the geometric imperfections of specimens. The simulated result showed good agreement with the test results.On the basis of test investigation, Influences of parameters including the length of members, the thickness of the plate, the width of additional stiffening lips, the height of stiffening ribs on the stability behavior of rack uprights were analyzed by ANSYS . The results indicated that the width of additional stiffening lips had effects on ultimate load-carrying capacity of distortional buckling and flexural-torsional buckling obviously. Moreover, the height of stiffening ribs had effects on ultimate load-carrying capacity of local buckling. The effect of the length and the thickness of the upright on the buckling modes of members cann't be ignored.