PSI - Issue 72

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

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3. Results and discussion After the experimental tests, the deformation measurement results were processed. The analysis of the experimental studies of glued laminated beams under direct bending was conducted based on "deflection-bending moment" graphs. The deflection values were taken as the average between the results of tests on two beams (GLB-1 and GLB-2). The processing of theoretical calculation results in the "LIRA SAPR" software was performed using a similar "deflection bending moment" graph. This graph for beams GLB-1 and GLB-2 is shown in Fig. 3.

Fig. 3. Experimental and theoretical deflections of glued laminated beams under direct bending

The analysis of the experimental studies showed that under direct bending, the deflections increased proportionally with the increase in load. The theoretical calculations demonstrated an almost directly proportional relationship between deflections and bending moments. The displacement isofields of the beams in the "LIRA SAPR" software are shown in Fig. 4.

-13.8

-12.1

-10.3

-8.61

-6.89

-5.17

-3.44

-1.72

-0.0237

0.0237

1.72

2.37

0,2 Mmax

Fig. 4. Isofields of beam displacements under direct bending in the "LIRA SAPR" software

The experimental deflection values under direct bending were slightly lower than the theoretical ones. This was observed throughout the entire beam testing process, from the initial loading to failure. Thus, it can be concluded that the theoretical calculations provide a certain safety margin for glued laminated beams under direct bending conditions. During tests on oblique bending, deflections were measured in the horizontal (axis Y-Y) and vertical (axis Z-Z) directions. The total deflection values for oblique bending were determined using the formula from DBN B.2.6 161:2017: = √ 2 + 2 , (1)

wherew y is the deflection along the Y-Y axis, mm; w z is the deflection along the Z-Z axis, mm.