Optimal orientation of cross-sections of columns of 3D steel frames in a single and multi-objective optimization

Resumo

In most structural optimization problems, the minimization of the structure’s weight is a traditional
objective. Furthermore, it is expected to improve other aspects of the optimum design, leading to conflicting
objective functions. This paper analyses single and multi-objective structural optimization problems of a six-story
space steel frame, considering the structure’s weight minimization as the first objective function and the second one
concerning the maximum horizontal displacement at the top of the frame to be minimized. The design variables are
the profiles assigned to the beams and the profiles assigned to the columns in which their orientations, concerning
the principal axes, are also design variables. Pareto fronts with the non-dominated solutions are presented. A
Multi-Tournament Decision method is adopted to extract solutions from the obtained Pareto fronts based on the
decision maker’s preferences. The search algorithm adopted is the Third Step Differential Evolution (GDE3)
coupled with an Adaptive Penalty Method (APM) to handle the constraints.