PSI - Issue 81

Mykola Pidgurskyi et al. / Procedia Structural Integrity 81 (2026) 539–546

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Fig. 7. Stress distribution along the beams: (a) lower flange without haunches; (b) lower flange with haunches; (c) upper flange without haunches; (d) upper flange with haunches However, as shown in Table 2, there are several perforations at whose edges the maximum stresses reach levels of 500 – 700 MPa. This is attributed to the fact that the analysis was performed using the finite element method within the framework of linear elastic behavior. In reality, under rational structural design and with the use of structural steel S345, local plastic deformations will develop in the vicinity of these perforation edges, which are unavoidable in regions of stress concentration. The adverse effects of such local plastic deformations include a reduction in the material’s ductility reserve and the potential initiati on of local damage; however, these effects are not critical for the service performance of such structures (Fares et al., 2016). Future studies will focus on evaluating the influence of larger pitch angles on the stress – strain state of perforated beams. 4. Conclusions 1. The combined influence of beam pitch, rigid end restraints, and strengthening elements (haunches) on the stress – strain state of perforated beams was investigated. For this purpose, numerical modeling of steel perforated beams of different types – horizontal, double-pitched, and arched was performed using the finite element method in the ANSYS software environment. The models accounted for actual geometric parameters, applied loads, rigid boundary conditions, and the presence of structural stiffening elements (haunches) at the joints. 2. The deflection analysis showed that horizontal beams exhibit the largest deflections, whereas double-pitched and arched beams demonstrate significantly lower deflections due to a more favorable internal force distribution. Compared to the horizontal beam, the double-pitched perforated beam without haunches showed a 58.3% lower deflection, while the arched beam showed a 63.5% lower deflection, with only a 0.9% increase in self-weight. The installation of haunches at the eaves and apex joints