PSI - Issue 81

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

421

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Fig 7. Comparison of eigenmode spectra for three frame models

The analysis of the frequency graphs for the three computational sets (Fig. 7) allows for a clear identification of the differences in the dynamic behaviour of the examined structural systems. Model option 3 demonstrates the widest range of natural frequencies, signifying considerable frame rigidity and a synchronous reaction of its components within modal forms defined by more intricate spatial arrangements. In contrast, option 2 generates a frequency distribution of intermediate magnitude, reflecting moderate and well-balanced stiffness. This system does not reach the maximum stiffness levels but neither enters a regime of reduced resistance to deformation effects. Conversely, option 1 exhibits the lowest natural frequency values, a hallmark of enhanced structural flexibility and a propensity for greater displacements under dynamic excitation. Conclusions The present study investigates the influence of structural modifications on the natural frequencies of a single-storey industrial building. The analysis demonstrates that each considered structural configuration exerts an influence on the spatial stiffness of the system and its amplitude – frequency response. The fundamental structural arrangement demonstrated the lowest natural frequency values, signifying enhanced flexibility and elevated displacements under dynamic loading conditions. This behaviour suggests that the basic configuration is less efficient when subjected to wind and seismic actions. The introduction of supplementary components to the upper portion of the frame resulted in modest enhancements to the natural frequencies, thereby optimising the dynamic response within the mid-frequency range. However, the most significant increase in stiffness was achieved in the configuration with cross bracing in the lower chord of the truss. The model demonstrated the highest natural frequency values, indicating the formation of a more rigid and spatially stable structural system. A comparative analysis, based on finite element modelling, was conducted to ascertain the influence of modifications to the lower chord on the dynamic characteristics of the structure. The findings of the analysis confirmed that such modifications have a substantially greater influence on the dynamic characteristics of the structure than reinforcement of the upper chord. References Avramov, K.V., Mikhlin, Y.V., Kurilov, E., 2007. Asymptotic analysis of nonlinear dynamics of simply supported cylindrical shells. Nonlinear Dynamics 47, 331-352 doi:10.1007/s11071-006-9032-1 Bardell, N.S., Dunsdon, J.M., Langley, R.S., 1997. On the free vibration of completely free, open, cylindrically curved, isotropic shell panels. Journal of Sound and Vibration 207,647-669 https://doi.org/10.1006/jsvi.1997.1115 Hud, M., Ihnatieva, V., Baran, D., 2024. Influence of mass distribution on natural vibrations of a reinforced concrete building frame. Procedia Structural Integrity 59, 692-696 https://doi.org/10.1016/j.prostr.2024.04.098 Iasnii, V., 2020. Technique and some study results of shape memory alloy-based damping device functional parameters. Scientific Journal of TNTU 97(1), 37 – 44 doi:10.33108/visnyk_tntu2020.01.037 Pellicano, F., Avramov, K.V., 2007. Linear and nonlinear dynamics of a circular cylindrical shell connected to a rigid disk. Communications in Nonlinear Science Numerical Simulation 12(4), 496-518 https://doi.org/10.1016/j.cnsns.2005.04.00 Pradyumna, S., Bandyopadhyay, J.N., 2008. Free vibration analysis of functionally graded curved panels using a higher-order finite element formulation. Journal of Vibration and Acoust 318(1), 176-192 https://doi.org/10.1016/j.jsv.2008.03.056 Yasniy, P.V., Mykhailyshyn, M.S., Pyndus, Y.I., Hud, M., 2020. Numerical Analysis of Natural Vibrations of Cylindrical Shells Made of Aluminum Alloy. Materials Science 55(1), 502 – 508 https://doi.org/10.1007/s11003-020-00331-2 Yasniy, P., Pyndus, Yu., Glad’o , V., Okipnyi, I. , Shul’gan , I., 2011. Scientific and technical section FEM prediction of the influence of warm prestressing on fracture toughness of heat-resistant steel. Strength of Materials 43(2), 113-121 doi:10.1007/s11223-011-9277-x