Analysis of local buckling in steel Rectangular Hollow Section via Lumped Damage Mechanics

This paper presents a lumped damage model to analyse local buckling in steel Rectangular Hollow Section (RHS). In this model, the nonlinear and damage effects of the planar frame element are concentrated in plastic hinges located at the ends of the element, significantly reducing the computational cost of the analysis. Thus, plasticization is represented by the formation of plastic hinges, while local buckling is described by the addition of a damage variable to these hinges. The analysis adopts a step-by-step procedure to consider geometric nonlinearity, solving the problem sequentially and considering the change in the geometry of structural elements. To evaluate the accuracy of the model, the numerical results were compared with experimental results, in which steel RHS were subjected to compressive axial force with monotonic bending moment loading. The results indicate that the numerical model presents satisfactory behaviour in relation to the experimental results.