Structural Optimization of trusses considering different buckling models

Resumo

Constraints related to buckling usually have a significant impact in the structural optimization of trusses,

and may be evaluated by employing different models. In this paper, an approach that considers a single global sta-
bility constraint, related to the so-called inelastic critical load, is presented and compared with other approaches

widely used in the literature. In this approach, each element of the truss is discretized into several frame elements.

After applying geometrical initial imperfections in the structure, inelastic buckling can be taken into account im-
plicitly via second-order inelastic analyses. The optimal structures obtained by employing inelastic critical loads

for the entire structure, as well as those obtained by considering, for each one of the truss elements, Euler buckling
loads or the inelastic buckling loads given in the AISC code, are compared. The optimization problems addressed
herein may demand high computational efforts, especially for the inelastic analyses, thus a previously proposed
optimization framework based on surrogate models is employed. As a result, higher objective function values
occur when the model from the AISC code is used. Furthermore, the inelastic model can lead to structures with
large displacements, so the displacements must be limited to result in more realistic designs.