PSI - Issue 81

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

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Fig. 5. Deformation diagrams of stud joints under low-cycle loads: a – nail joints 1; b – nail joints 4 Samples 5 were loaded to the upper level with initial shear strains equal to those in the first loading cycle сус ,1 =1.5 mm, at which the upper level of low-cycle loads was 16.6 kN. The shear deformations constantly increased with each subsequent loading cycle (Fig. 6).

Fig. 6. Deformation diagram of nail joints 5 under low-cycle loads The upper level of low-cycle loading at which nail joints 3 were tested was fixed at 16.0 kN at the initial shear deformation in the first test cycle сус ,1 =1.4 mm. In the following cycles, there was a constant gradual increase in deformations: in the second cycle their increase was 7.8%; in the fifth – 13.9%, which accordingly amounted to сус ,2 =1.51 mmand сус ,5 =1.595 mm. In the tenth cycle, the increase in deformations from the first cycle was 21.8%, in the twentieth - 28.2% and reached сус ,10 =1.705 mm and сус ,20 =1.795 mm in accordance. The achievement of the maximum shear deformations of the joints by average values occurred on the 23rd loading cycle (Fig. 7). Samples 6 were loaded to total shear strains in the first cycle сус ,1 =1.2 mm at the same time, the load was 15.9 kN. In the second loading cycle, the resulting deformations were сус ,2 =1.25 mm, and in the fifth and tenth cycles the total deformations reached accordingly сус ,5 =1.35 mmand сус ,10 =1.475 mm. The increase in shear strain between these cycles was 8.0% and 9.3%, accordingly. The total residual deformations after the twentieth loading cycle were 0, сус ,20 =1.005 mm, on the fiftieth cycle they reached a value of 0, сус ,50 =1.16 mm(Fig. 8).