M. A. Karyukin Multivariate Modeling of Design Parameters of Elastic Clips of Modern Rail Fasteners, with Analysis of Their Stress-Strain State [more] [back]
Purpose: To determine the influence of geometric parameters on the most common elastic rod clip used in modern intermediate rail fastenings — the B-shaped clip (such as reinforced concrete rail (RCR) clip and anchor rail fastening (ARF)) — on changes in its stress-strain state. To propose a further direction of improving the design of elastic rod clips of rail fasteners to increase the reliability of the structure. Methods: The article presents the results of multivariate modeling of the geometric parameters of the clips (RCR — 20 pcs., ARF — 13 pcs.) with the analysis of their stress-strain state, using the methods of software and computer systems SolidWorks and Ansys Workbench. Results: Analysis of the design of modern fasteners has shown that the intervals for varying the geometric parameters of the clips (rod diameter, vertical radius, horizontal radius) have small limits and significant limitations associated with the requirements for ensuring the strength, elasticity and operability of the entire fastening. The necessity of considering options with vertical radii less than 60 mm has been revealed, which entails the need for a radical change in the shape of the clips themselves. Practical significance: As a result of the analysis of the calculations of multivariant models, the degrees of influence of the intervals of variation of the geometric parameters of rod clips (rod diameter, vertical radius, horizontal radius) on the stress-strain state have been determined. It is established that in order to further increase the elasticity of the clips, it is necessary to develop a new type of rail fastening with a fundamentally different shape (different from the modern B-shaped) elastic clip that does not have modern design limitations in geometric parameters. Keywords: Railway track, rail fastening, software and computing complex, SolidWorks, Ansys, geometric parameters, stresses
D. V. Danilenko, V. P. Efimov, V. A. Chernov Research on Fatigue Durability of Side Bearing Springs for Model 18-9891 Bogie [more] [back]
Purpose: To conduct comprehensive experimental studies on the fatigue strength of side bearing springs for freight bogies, evaluating the effectiveness of thermal and shot peening treatments during their manufacturing process. Methods: The method of stand endurance (fatigue) testing of constant contact side bearing springs has been applied, allowing for obtaining endurance characteristics of actual components. Metallographic studies of spring steel have been conducted to investigate the influence of strengthening operations during spring manufacturing on their fatigue strength, with the assessment of mechanical characteristics of surface layers in various zones of the helical spatial beam. Results: Experimental force characteristics of spring sets for side bearings of an innovative freight bogie with a load of 25 tons (245 kN) on the axle have been obtained. Fatigue curves of the springs have been presented in a probabilistic aspect, enabling the determination of load factor for fatigue strength of the springs considering operational loading, as well as justifying the compliance of the spring sets with the regulatory requirements. Practical significance: Based on the research results, the considered constructive-technological variant of the constant contact side bearing spring for the freight bogie has been put into serial production. The test results allow us to reasonably determine the warranty mileage of the responsible assembly of the bogie and to conduct further work on the design modernization with the aim of increasing operational life. Keywords: Fatigue strength, springs, side bearing of a freight bogie, metallographic studies of spring metal
S. T. Jabbarov, N. B. Kodirov Analysis of the Impact of Wheel Dynamic Load on Rails under High-Speed Train Operations in Uzbekistan [more] [back]
Purpose: Justification of choosing the factors influencing the formation of dynamic load on the railway track by modern rolling stock during high-speed and very high-speed operations. To achieve this goal, theoretical groundwork and experimental research have been conducted. As a result of the work, a methodology has been developed for determining the vertical calculated force exerted by the wheel on the rail. Methods: High-speed and very high-speed trains, due to their fundamental design and significant increase in speed, necessitate a reconsideration of methods for calculating the impact of rolling stock on the railway track. This includes the analysis of relationships between root-mean-square deviations of various dynamic forces and the assessment of the influence of different factors at different speeds of operation. Results: As part of the study, experimental measurements have been conducted to examine changes in dynamic load. As a result, dependencies between the average and calculated vertical forces and the speed of operation for modern passenger trains have been obtained. By using factorial analysis of variance, numerical characteristics of the influence of various factors on the value of the vertical force exerted by the wheel on the rail have been obtained. Additionally, the degrees of influence of different factors on the formation of this force have been determined. Keywords: Track strength calculation, track superstructure, high-speed operation, track stress, dynamic force, dynamic inequality