Issue 75

P. Grubits et alii, Fracture and Structural Integrity, 75 (2026) 124-156; DOI: 10.3221/IGF-ESIS.75.10

In addition to the previously discussed results, Tab. 11 presents the cross-sectional types corresponding to the best- and worst-performing cases for both optimization setups, E2-OP1 and E2-OP2, together with the reference configuration. Relative to the latter, a total weight reduction of approximately 7.5% was obtained for the least efficient optimized case, while the best-performing design achieved a 19.1% decrease. Notably, as mentioned earlier, all structural requirements were fulfilled in the optimized designs. In contrast, the initial configuration failed to reach the predefined load-bearing capacity— attaining only 61.5% of 0 P —and did not satisfy the stability criterion ( 0.388 1.000    ˉ ). Consequently, the reference setup exhibited inferior performance despite its greater material usage. These outcomes further highlight the effectiveness of the proposed automated optimization framework in producing lightweight yet structurally compliant designs. The corresponding cross-sectional area distributions for the best and worst configurations obtained in both E2-OP1 and E2 OP2 are illustrated in Fig. 30.

(a)

(b) Figure 30 : Cross-sectional area distribution for the best and worst configurations of (a) E2-OP1, and (b) E2-OP2 in the 25-bar truss. Furthermore, as shown in Tab. 11, both the best and worst configurations obtained in E2-OP1 satisfied the serviceability requirement defined by the displacement limit max (max ) y y U U  , even though this constraint was not active during the optimization process. This result can be attributed to the definition of the design space, which inherently promotes relatively stiff structural configurations compared to the prescribed displacement threshold   max 12.70mm U  . Consequently, the displacement constraint exerted no significant influence on the optimization outcome, explaining the close similarity observed between the results of E2-OP1 and E2-OP2.

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