PSI - Issue 81

Olena Mikulich et al. / Procedia Structural Integrity 81 (2026) 251–254

254

4. Conclusions Analysis of the numerical results of the results presented in Fig. 5 allows us to formulate the following conclusions: 1. The developed methodology allows us to take into account the influence of the microstructure of the material, since the analysis of the stress distribution when loading only one of the holes is not the same. This is explained by the fact that within the framework of the couple stress elasticity, the influence of shear-rotational deformations of points of the medium is taken into account. Based on the corresponding calculations for specific types of problems, it is possible to take into account the mutual influence of defects in the medium with accounting their microstructure. 2. The developed methodology allows us to analyze the stress state for the case of cavities of different sizes and shapes, since it is based on the use of the indirect approach of the boundary element method. In addition, the use of conformal mapping to describe the boundaries allows us to perform calculations for the case of cavities of a non-circular shape. 3. Analysis of the stress state allows us to form conclusions about the reflection of waves from the boundaries of the cavities, on the basis of which we can conclude about the interaction of defects in the medium. In Fig. 5 shows the superposition of waves, due to which a higher stress arises in the medium than that applied to the boundary. 4. Further research will be aimed at conducting numerical experiments for cavities of different sizes under different types of loading. References Alradha, R., Alatabi, R. 2018. The Effect of UV-Radiation on Mechanical and Chemical Properties of Polyurethane/ nanoTiO2 Sizing by Unsaturated Polyester. Journal of University of Babylon for Engineering Sciences 26(10), 265-272. Ates, M., Karadag, S., Eker, A.A. and Eker, B., 2022. Polyurethane foam materials and their industrial applications. Polym Int, 71: 1157-1163. Barszczewska-Rybarek, I., Jaszcz, K., Chladek, G.et al.2022.Characterization of changes in structural, physicochemical and mechanical properties of rigid polyurethane building insulation after thermal aging in air and seawater. Polym. Bull. 79, 3061 – 3083. Dong, H., Li, S., Jia, Z., Luo, Y., Chen, Y., Jiang, J., & Ji, S., 2024. A Review of Polyurethane Foams for Multi-Functional and High-Performance Applications. Polymers, 16(22), 3182. Kim, S., Li, K., Alsbaiee, A., Brutman, J.P., Dichtel, W.R., 2023. Circular reprocessing of thermoset polyurethane foams. Adv. Mater., 35:2305387. Mikulich, O. 2023. Dispersion Properties of Waves in Polyurethane Foam. In: Ivanov, V., Pavlenko, I., Liaposhchenko, O., Machado, J., Edl, M. (eds) Advances in Design, Simulation and Manufacturing VI. DSMIE 2023, LNME, pp. 230 – 236. Mikulich, O., Hulay, O., Furs, T., Shemet, V., 2024. Strength and mechanical characteristics of modified polyurethane foams. Procedia Structural Integrity, 59(21), 460-465. Mikulich, O., Shvabyuk, V. 2021 Investigation of impulse load attenuation in closed-cell foam in the framework of couple stress elasticity. IOP Conf. Ser.: Mater. Sci. Eng., 1164, 012052. Shi, L., Gong, Z.,Xie, M.,Shao, W.,Cheng H.,Gao, S., 2025. Photodegradation behavior of different polyurethane: a comparison study of foam and leather. Journal of Environmental Sciences 7. Wang, C., Murugadoss, V., Kong, J., He, Z., Mai, X., Shao, Q., Chen, Y., Guo, L., Liu, C., Angaiah, S., 2018. Overview of carbon nanostructures and nanocomposites for electromagnetic wave shielding. Carbon, 140, 696-733.