Buckling resistance of metal columns with smoothly variable cross sections

Metal columns of hollow and smoothly variable cross-sections, simply supported at their ends are considered in the paper. Columns of such shapes are recently frequently designed by architects in public utility buildings of various types. In this work authors present the comparatively simple method of buckling resistance assessment which can be used by designers of metal columns of such shapes. The formula on critical force required in the procedure was derived for columns of variable cross section by means of MathematicaTMsystem. The closed formulae were obtained for a rod with a certain, predefined geometry being the surface of revolution. Critical forces obtained by means of derived formulae were compared with results of numerical solutions. To assess the compression resistance of considered rods the general Ayrton-Perry approach was applied and bow imperfection with assumed amplitude was used in the analysis. Results of numerical simulations and experimental tests inserted in the paper confirm the correctness and the effectiveness of the proposed procedure of buckling resistance assessment of considered struts.