PSI - Issue 81

Valentin Aleksiievets et al. / Procedia Structural Integrity 81 (2026) 422–429

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 5 → = =1.5 ;  3 → = =1.4 ;  6 → = =1.2 ;  7 → = =1.0 ;  8 → = =0.8 . That is, during the first loading cycle, the initial required shear deformation of the connection was achieved, at which a certain load value u  F was fixed. The connection was unloaded to zero. The low-cycle load was applied for such a number of cycles until the total shear deformations of the joint reached mm u 2.0   . Test mode for nail joints with short-term loads can be seen on fig. 4.

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b

Fig. 4. Test mode for nail joints with short-term loads: a) generalized diagram  Т of the operation of nail connections; b) change of F over time when testing joints with step loading 3. Results and discussion Nail joints 1 were tested under a load of 23.0 kN, which corresponded to the initial deformations сус ,1 =1.8 mm, during the second loading cycle, the load-bearing capacity of the samples was lost with the achievement of ultimate crushing deformations 2   u mm. After testing and processing of experimental data, results were obtained, which in turn made it possible to construct deformation diagrams of nail joints (Fig. 5). The load of joints 4 was 17.4 kN and the initial deformations in the first loading cycle were сус ,1 =1.6 mm. After processing the test results, it was found that in the second loading cycle the increase in the average total shear deformations was 0.085 mm, in the fifth – 0.25 mm, which accordingly reached сус ,2 =1.685 mm and сус ,5 =1.85 mm. The loss of load-bearing capacity of one of the samples occurred at the 9th loading cycle (Fig. 5).