Inelastic Post‐buckling Analysis of Trusses

Abstract

Geometric and physical nonlinearities are considered in the investigation of the post‐critical ultimate load conditions of space trusses. The inelastic behavior of struts is accounted for by tracing the complete stress‐strain relationships in the elastoplastic range. The unloading characteristics of struts in the post‐critical elastic‐perfectly plastic stage are determined and the irreversibility of plastic strains are considered through an incremental procedure. The dynamic relaxation method is used for the solution of the nonlinear algebraic equilibrium equations. The method does not require the evaluation of any stiffness matrix, but only direct use of the relatively simple force‐displacement relations of the individual discrete elements is needed. Numerical examples are presented for two test problems and comparative results are obtained for different stress‐strain laws.