PSI - Issue 36

Yaroslav Shved et al. / Procedia Structural Integrity 36 (2022) 10–16 Yaroslav Shved; Yaroslav Kovalchuk; Liudmyla Bodrova; et al. / Structural Integrity Procedia 00 (2021) 000 – 000

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Similar studies according to the described method were performed for the other four structural variants of trusses with different shelf sizes of the angular profile (see table. 1). The obtained results are summarized in the table. 3.

Table 3. Indicator for optimizing the design of 18000 × 3600 mm truss by the number of corner elements. Angle bar 80 × 80 × 10 90 × 90 × 10 100 × 100 × 10

120 × 120 × 10

140 × 140 × 10

Truss weight, M, kg

801.16

908.4

1015

1229

1442

Ppl., N

340 405

405 507

498 620

703 775

805 870

Pmax, N

Ppl / M, N / kg Pmax / M, N / kg

0.424 0.505

0.445 0.558

0.491 0.610

0.572 0.630

0.558 0.603

The last two rows of the table show the strength of the structure per mass unit under load at the limit of plasticity (Ppl / M, N / kg) and at the level of the limit state (Pmax / M, N / kg). 5. Optimization of the truss structure by the size of the shelf of angular elements The initial data for optimization is the results of computer simulation of the truss behavior under the action of static loads (summarized in the table. 3). According to the table. 3 graphs of indicators for optimization were built (fig. 5). According to the graph, the non-linearity of optimization parameters is obvious, which complicates the search for optimal solutions by simple engineering calculations. According to the graph in Fig. 5b, it is clear that the optimal ratio of strength and material consumption for the studied truss structure is 120x120x10 mm angle bar, for which the strength of the structure per mass unit is the highest.

Fig. 5. (a) summary graph of strength P and material consumption M indicators: 1-maximum load at the level of the limit state; 2-load on the limit of plasticity of the material; 3-material consumption of the structure; (b) specific strength of the truss: 1-on the verge of plasticity (Ppl / M, N / kg); 2-at the level of the limit state (Pmax / M, N / kg). 6. Conclusions The paper solved the problem of designing welded rafter truss with the optimal ratio in strength and material consumption. Optimization criteria are proposed and the expediency of using these criteria for welded trusses is substantiated. It was proposed the method for optimizing the construction of a rafter welded truss using the ANSYS Workbench 14.5 software package for a variable number of the angle bar within the standardized profiles for the truss. The results of the computer modeling experiment reveal the quantitative and qualitative patterns of the behavior of the welded truss under the action of static loads within the change of the number of the angular profile of the truss elements.