PSI - Issue 72

Andrii Pavluk et al. / Procedia Structural Integrity 72 (2025) 330–337

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natural material (Roshchuk et al. (2024), Galicki and Czech (2005),Homon et al. (2023), Anshari et al. (2017), Yasniy et al. (2022), Sinha et al. (2012)) and can be used under varying humidity conditions (Homon et al. (2023), Thygesen et al. (2010), Janiak et al. (2023), Madsen (1975), Huang et al. (2006)).

Nomenclature w

total deflection of the beam under bending deflection of the beam along the axis Y-Y deflection of the beam along the axis Z-Z ultimate deflection of the beam under bending

w y w z

w fin

span of the beam bending moment

l

M

Oblique bending occurs when the direction of the applied load does not coincide with any of the principal axes of the cross-section (Pavluk et al. (2024), Gomon et al. (2024), Sobczak-Pi ą stka et al. (2023)). Oblique bending arises in beams, spans, battens, roofing and bridge elements, as well as inclined overpasses (Gomon et al. (2023), Pavluk et al. (2023)). The practice of designing wooden structures shows that the number of elements subjected to oblique bending accounts for 18-22% of the total number of bending elements. Considering the anisotropy of wood, the presence of defects and damage, as well as the variety of its grades in glued beams, it can be concluded that wooden bending elements, to some extent, are affected by oblique bending. In connection with the increasing use of wood in construction, the study of beam bending is highly relevant today. This is especially true for oblique bending, as it represents a complex stress-strain state that has not yet been sufficiently studied. The current design standards (DBN B.2.6-161 (2017), Eurocode 5 (2004)) do not account for the specific behaviour of glued laminated beams under oblique bending, particularly the actual changes in the stress-strain state of such elements from the initial application of the load to failure. At present, the behaviour of wood in structures is assumed to be conditionally elastic, which does not fully correspond to its actual performance. The study of the deformation process and the determination of the features of the stress-strain state of obliquely bent elements will allow for more accurate calculations of glued laminated beams at various load levels. 2. Methodology of experimental and theoretical research The experimental part of the research involved testing glued laminated beams under direct and oblique bending. An experimental setup was designed and constructed for conducting the tests (Fig. 1).

Fig. 1. Diagram of the experimental setup for testing beams under direct bending