Single and multiobjective frame optimization by evolutionary algorithms and the auto-adaptive rebirth operator

The constrained minimum-mass problem of middle-size frames is taken into account, for both continuous and discrete cases with ideal (without buckling effect and own gravitational load) and real (with both) models, comparing three strategies of evolutionary algorithms. Some proposals to obtain appropriate results in middle-sized frames are exposed: optimization considerations about coding and structure; and the introduction of the auto-adaptive rebirth operator. Moreover, the introduction in the initial population of high quality single-optimization solutions obtained via the auto-adaptive rebirth operator is proposed as a way to improve the final non-dominated fronts obtained in structural frame multicriteria optimization (number of different cross-section types as second criteria). The results through three test cases (55–35 bar-sized) show the advantageous use of the auto-adaptive rebirth operator in frame optimization.