Issue 75

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

(c) Figure 21: Cross-sectional area distribution for the best and worst configurations of (a) E1-OP1, (b) E1-OP2, and (c) E1-OP3 in the 37-bar truss.

B ENCHMARK NUMERICAL EXAMPLE : 25- BAR SPACE TRUSS

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his section presents the second numerical example, the well-known 25-bar truss structure. Two elasto-plastic optimization setups were conducted—one with a displacement constraint and one without—and the resulting solutions were compared to evaluate the effectiveness of the proposed methodology. Initial finite element setup and structural response of the 25-bar truss Consistent with the operation of the proposed framework, the FE model of the 25-bar truss was constructed using the same modelling technique as in the first numerical example. Accordingly, this section highlights the key differences in the structure. In this benchmark, the members are divided into eight design groups, each governed by a common cross-sectional area variable, as shown in Fig. 22(a). In this case, the same sections listed in Tab. 2 are considered as design variables. The initial setup was constructed as follows: groups 1-3 are assigned CHS 48.3/4.0, and groups 4-8 are assigned CHS 88.9/4.0. Consequently, the cross-sectional area distribution of the structure is shown in Fig. 22(b). This initial setup—including its structural weight , 599.34kg s init G  assuming material density 3 7850kg/m   —serves as the reference configuration for the optimization results presented in the subsequent section.

(a) (b) Figure 22 : The 25-bar truss: (a) structural layout; (b) distribution of cross-sectional areas assigned to each member in the initial configuration.

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