Khomiak, YuriyKibakov, OleksandrGerasymov, Igor2024-01-012024-01-012023Khomiak Yu. Determination of characteristics of fatigue cracks growth in the axles of railway carriages / Yu. Khomiak, O. Kibakov, I. V. Gerasymov // Вісник Національного технічного університету "ХПІ". Сер. : Машинознавство та САПР = Bulletin of the National Technical University "KhPI". Ser. : Engineering and CAD : зб. наук. пр. – Харків : НТУ "ХПІ", 2023. – № 2. – С. 122-128.https://repository.kpi.kharkov.ua/handle/KhPI-Press/72440Providing damage resistance is the most important requirement presented to railway axles. This paper provides a detailed review of the characteristics of resistance to fatigue crack growth in axles made of EA4T steel (25CrMo4). This steel is typical for axles of high-speed rolling stock. Resistance to fatigue crack growth is defined by the nature of the Paris-Erdogan curve da/dN=CKm, the parameters of which are the coefficient C and the exponent m. Determination of these parameters is based on the results of fatigue tests with the samples or with full-scale axles having cracks. The analysis of numerous scientific papers has shown that for the specified steel there is a significant scatter in the values of these parameters. This scatter is caused by a number of factors, the main of which are: the difference in test objects (from small samples of the SE(B) type to full-scale rolling axles 190 mm in diameter); the difference in loading methods (tension-compression, flat bending, circular bending); the variation of mechanical properties of EA4T steel. In the paper the models of surface fatigue crack geometry are analyzed and semi-elliptical shape of crack front line is selected as the most acceptable. The significant scatter in the values of the parameters m and C prevents to establish reliably the residual life of axles with cracks, which is an important characteristic for practical forecasting of axle survivability. The technique for parameters m and C optimization in view of semi-elliptical shape of the crack front line has been developed. The relationship linking the parameters m and C has been established. The method for determining the residual life of the axle by the criterion of non-destruction is proposed. The dependence between the residual life and the value of the parameters of the Paris-Erdogan equation in the development of fatigue failure is established. The procedure for axles monitoring timeframes setting to prevent their fatigue failure is discussed.enparameters of Paris-Erdogan equationfatigue crackresidual life of axleпараметри рівняння Періса-Ердоганавтомна тріщиназалишковий ресурс осейArticledoi.org/10.20998/2079-0775.2023.2.13https://orcid.org/0000-0003-0093-8405https://orcid.org/0000-0001-8339-345Xhttps://orcid.org/0009-0005-5284-0372