PSI - Issue 72

Andrii Ivaniuk et al. / Procedia Structural Integrity 72 (2025) 323–329

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Fig. 1. Scheme of tests of beams with a crack located along the neutral axis

Beam deflections were determined using the readings of the deflection meters. The loading on the beams was carried out in stages. The magnitude of the load steps was approximately 10% of the permissible destructive load. At each level of load, indicators were recorded for all devices. In addition, a 20-minute hold was given at each load level. The loading time of one stage was 2…3 minutes. T he crack displacement was determined both visually and by the readings of clock type indicators. The indicators were installed in the middle of the so-called half-cracks l 1 and l 2 and allowed measuring the relative displacement of the crack edges. The value of the destructive force P was taken to be the load value at which crack displacement was observed. The general view of the beam tests is shown in Fig. 2.

Fig. 2. General view of the beam tests

Tests were conducted according to current standards (DBN B.2.6-161:2017, DSTU 3129: 2015, Eurocode 5:2004). 3. Results and discussion For the tested beams, experimental stress distributions are given, the average values of which are taken on two sides of cross-sections 1-1, 2-2 and the lower and upper faces of beams B1, B2, B3, as well as the lower and upper