Abstract. In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the vertical K vd and horizontal K hd dynamic coefficients as well as the stability coefficient K s , which determines the wheel flange resistance to derailment. The article compares dynamic indications for three different types of bogies. There were no tangible differences observed for all the three different types of bogies running at a speed of 40 to 120 km/h on a direct tangent rail section. Nevertheless, there is a realistic potential to improve the dynamic indicators of a freight wagon by rationalising suspension unit parameters.
Abstract. The article presents a mathematical model for assessing the real operating conditions of railway rolling stock, taking into account the situations when the wheel loses contact with rail. The obtained amplitudinal fluctuation characteristics depend on the set roughness function and the running speed of the wheel. When calculating dynamic processes, the contact between wheel and rail should be considered unstable. With the increase of speed, the impact of this instability increases.
Purpose. To ensure the constantly growing volume of freight transportations it is necessary to introduce the innovation rolling stock. It should have the best technical and economic parameters in comparison with the existing fleet. Gondola car is the most popular type of railway freight car. Designs of the modern gondolas are based on many years of operating experience and numerous tests carried out by design and research organizations in the field of car building. To improve the body structure of gondolas it is necessary to perform a review of the existing structures and to identify the trends in their improvement. Methodology. The works on improvement the designs of produced gondolas are held by many engineering organizations in almost all industrialized countries. Analysis of the existing body designs of gondola cars is possible by analyzing the research in the field of transport engineering, namely patents, scientific articles, producers catalogues and so on. Findings. When analyzing it was determined that there are gondolas of different designs, but the most common are the gondolas with a solid floor and unloading hatches, the covers of which form the floor of gondola design. An effective method for reducing the gondola empty weight and increasing the body volume is also the use of aluminum alloy instead of steel. Results of the improvement analysis of the gondola bodies` designs showed that the creation of the modern gondola car requires from designers and scientists the implementation of scientific and technical solutions providing the increase of carrying capacity and the body volume, reduction of the gondolas empty weight, increase in repair intervals while improving the strength and dynamic qualities at the same time. Originality. For the first time the gondolas designs were analyzed, their advantages and disadvantages were considered and the trends in improvement of the given structures of gondola cars were determined. Practical value. The generalization of theoretical, scientific and methodological, experimental studies aimed at further improving the technical and economic parameters of gondola cars are urgent when improving the body structure of the gondola cars. The above mentioned design features of the bodies of some models of modern gondola cars have practical value and can be used in further developments.
The Monograph deals with the simulation of oscillation damping units -the shock absorbers and oscillation dampers. Various types of draft gears are considered including their structural features and mathematical models describing their operation. The test methods for oscillation dampers and draft gears are described together with the test results processing techniques.The book is issued for the scientists and designers researching and developing various shock absorbing units in railway vehicles. It may be useful for postgraduate, master degree and other students studying the structure and dynamics of the railways rolling stock and industrial transport. INTRODUCTIONThis monograph brings to the experts' notice the mathematical modeling of draft gears and shock absorbers. The mathematic description of these units functioning that can be used when studying the vehicles dynamics is connected with the specific features of their structure.Wedged friction draft gears with steel friction elements tend to lock if friction is not stabilized. Therefore, when modeling dynamic process in a train, it was typical to assume the gears compression forces subject to the identification of their qualitative and quantitative train dynamic process parameters, but not the forces that resulted directly from the specific features of their structure. In some publications [3,101,102], these parameters are called integral. The same publications showed that, actually, they were just some static characteristic of the gears. The experience of transitional train motion modes (standing start, braking, motion in vertical track alignment breaks, coupled cars collisions) dynamic processes simulation evidences the appropriateness of such characteristics utilization when determining the forces acting on the train vehicles.The design of Mark plate type spring friction draft gears described in Freight Car Draft Arrangements Manual, 2003 Wabtec Corporation, and (PMK) draft gears [103] include elements (special lubrication and metal-ceramic parts) that significantly increase the energy capacity and stabilizing functioning of these draft gears. The correlation of these elements geometry with the gears force characteristics in general is detailed in publication [103].The ideas of a friction draft gear mathematical simulation presented in Chapter 2 are used in Chapter 3 when building the flat and spatial car bogie friction shock absorber model. The fundamental correlation of vertical and transverse horizontal oscillation produced by friction forces is shown.When modeling hydraulic and pneumatic (Chapters 4-9) draft gears, shock absorbers and dampers, stationary and non-stationary thermodynamic processes in the respective environment are considered. The processes occurring in the real gas and in the systems with variable working body weight are analyzed. The difference in draft gears and shock absorbers modeling results arising due to real gas environment versus ideal gas environment is demonstrated. New, formally derived, approximating equation and calculat...
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