PSI - Issue 81

Mykhailo Hud et al. / Procedia Structural Integrity 81 (2026) 486–492

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Fig 7. Frequencies of 2 opening frame model The graph shown (Fig. 7) reproduces the change in the natural frequencies of the structural frame system with two openings depending on the mode number and reflects the sequential dynamics of the vibration modes. The initial frequency values, ranging from 1.294 to 1.328 Hz, correspond to low-frequency global vibration modes, in which deformations cover a significant part of the frame and have a general spatial character. The further increase in frequencies occurs gradually: the values change in the range of 2.137 – 8.020 Hz, which indicates a smooth transition of the modal structure to more complex and rigid deformation modes characteristic of the mid-frequency range. The upper part of the spectrum shows the highest frequency values — 12.572 – 12.808 Hz, which are characteristic of localized or highly rigid forms of vibrations concentrated in individual elements or groups of elements. The absence of sharp frequency jumps or dips throughout the curve confirms the structural orderliness of the model and its predicted dynamic behavior, which indicates the correctness of the constructed calculation scheme and the consistency of the modal characteristics.

Fig 8. First form oscillations of 2 opening frame model

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Fig 9. Frequencies of balcony frame model