Comparison of different optimization methods applied to steel trusses structures

Resumo

The objective of the present paper is the adaptation and development of algorithms to minimize the
weight of trussed steel structures based on different optimization methods (mathematics and heuristics). Compare
the efficiency between the Sequential Quadratic Programming (SQP) and the Genetic Algorithm, taking into account
the quality of the solutions found, the complexity of implementation and the computational cost required. The
results show that, when using the technical standards for compressed bars, it is necessary to adopt bars with more
robust cross sections when compared to solutions whose restrictions derive from the classic formulation of Euler’s
critical load. A similarity between the results obtained by the SQP and the Genetic Algorithm is observed, but due
to the combinatorial nature of the latter, the heuristic method requires longer processing time. In addition, the results
obtained by the Genetic Algorithm are shown to be random during the iterations, and may converge in slightly
heavier solutions than the SQP. Justified by the results presented, it is stated that the developed algorithms are good
tools for structural optimization and can be used in real steel truss designs.