PSI - Issue 81

Mykhailo Hud et al. / Procedia Structural Integrity 81 (2026) 417–421

419

Fig 3. The third frame option

3. Result and discussion Following the execution of the requisite calculations, a series of numerical values was obtained. It is evident that this set comprises natural frequencies for all modes that have been defined within the analytical model. Moreover, detailed graphical materials were created for each mode, which reflected the values of natural frequencies according to a specific modal configuration.

1.4

1.2

1

0.8

0.6

Frequency (hz)

0.4

0.2

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Mode

Fig 4. Oscillation frequencies for frame option 1

The baseline model (Fig. 4) is characterised by the lowest natural frequency values, indicating reduced spatial stiffness of the structural system. It has been established that the system exhibits a sharp increase in natural frequencies within the range of modes 7 – 9, which is indicative of more complex vibration shapes developing in the higher modes. Within these defined parameters, there is an observable increase in the frame's sensitivity to external dynamic effects, most notably wind and seismic activity. These external forces exert influence on the frame's vibrational behaviour, which can be seen through the specific features exhibited.