A New Approach to the Stability Design of Ramberg–Osgood Material Struts

An energy formulation employing total potential energy principles is presented to derive a governing equation for strength predictions of struts made from materials following the Ramberg–Osgood constitutive law such as stainless steel, cold-formed steel, and aluminium alloys. The formula is generic and applicable to arbitrary cross-sections and all strut slendernesses for which flexural buckling is critical. Extensive comparisons against experimental data on square and rectangular hollow section struts as well as finite element simulations demonstrate the accuracy of the developed formula, while the effect of varying material parameters is examined through comprehensive parametric studies. Owing to its simplicity and its derivation based on mechanical principles, arbitrary configurations of material parameters and cross-sections can be analysed, making the formula suitable for use in design practice, representing effectively a non-iterative alternative to the widely accepted design load employing the tangent modulus. With the aid of the formula, new column buckling design provisions are developed, which show excellent agreement with experimental data and meet the reliability requirements specified within the structural Eurocodes.