PSI - Issue 81

Dmytro Voloshyn et al. / Procedia Structural Integrity 81 (2026) 264–268

268

n

i x x x H =  =    =  2 1 1 i i

x

(2)

n

Accordingly, the top event ‘tree’ with the logical sign ‘OR’ exists only if at least one of the initial events A 1 , A 2 , A 3 ... A n . In this case, the structural function for the box node takes the form:

n

i x x x H = =    =  2 1 1 i i

x

(3)

n

Next, the structural function obtained was recorded in algebraic form to formalise the reliability analysis process and simplify the calculations of the probability of failure-free operation and the probability of failure. The rules of Boolean algebra were used to convert Boolean variables into algebraic ones.

Fig. 4 . An example of an equivalent ‘failure tree’ for a bearing assembly.

As a result of the calculations, the probabilities of failure of the main components of the axlebox assembly were determined. During the analysis of axlebox assembly failures using the above method, it was found that the reliability of bearings in a typical assembly has a significant discrepancy between the normative and actual values. 4. Conclusions An analysis of the reliability of axlebox assemblies in operation was conducted. The main types of damage to bearing assemblies in operation were considered. Statistical data on failures are provided. The basic principles of constructing a graphological model of a ‘failure tree’ are considered with the aim of determining the necessary graphic symbols and appropri ate mathematical apparatus. The obtained model and data on the m ost ‘narrow’ points of the axle box assembly were analysed. It was concluded that the most vulnerable element is the outer rings of the bearings. Most often, roller bearing failures result from fatigue damage. The structural function of the axlebox assembly during operation was determined, and reliability indicators were calculated using a mathematical model. According to the calculations, the actual service life of freight wagon axlebox assemblies (operating time to failure) is no more than 3 years. This requires adjustments to the maintenance and repair schedules. References Biel, P., Szkoda, M., Machno, M., 2024. Analysis of the Impact of Selected Factors on Damage to Rolling Bearings of Rail Vehicle Wheelsets. Advances in Science and Technology Research Journal, 18(5), 206 – 216. https://doi.org/10.12913/22998624/190364 Entezami, M., Roberts, C., Weston, P., Stewart, E., Amini, A., Papaelias, M., 2019. Perspectives on railway axle bearing condition monitoring. Proceedings of the Institution of Mechanical Engineers , Part F: Journal of Rail and Rapid Transit, 234(1), 17-31. https://doi.org/10.1177/0954409719831822 Hou, Y., Wang, X., Wei, J., Zhao, M., Zhao, W.,·Shi, H., Sha, C . , 2024. Measured dynamic load distribution within the in situ axlebox bearing of high-speed trains under polygonal wheel – rail excitation. Railway Engineering Science, 32(4), 444 – 460. https://doi.org/10.1007/s40534-024-00344-6 Konecny, J., Ozana, S., Choutka, J., Prauzek, M., 2026. Towards railways safety: A systematic review on predictive diagnostics for axle bearings. Measurement, 257(A), 118510. https://doi.org/10.1016/j.measurement.2025.118510 Liu, C.; Zhang, X.; Wang, R.; Guo, Q.; Li, J., 2024. Vibration-Based Detection of Axlebox Bearing Considering Inner and Outer Ring Raceway Defects. Lubricants , 12(5), 142. https://doi.org/10.3390/lubricants12050142 Voloshyn, D.I., Holovko, V.F., 2004. Calculation of the potential for formless work of axlebox using form models. Collected scientific works. Kharkiv: UkrSURT, 57, 5-9. ISSN 1994-7852 [in Ukrainian] Yasniy, O., Lapusta, Y., Pyndus, Y., Sorochak, A., Yasniy, V., 2013. Assessment of lifetime of railway axle. International Journal of Fatigue, 50, 40 – 46. https://doi.org/10.1016/j.ijfatigue.2012.04.008