Browsing by Author "Reidemeister, Alexey G."
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Item Dependence of Air Spring Parameters on Throttle Resistance(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Reidemeister, Alexey G.; Kivisheva, Anastasiia V.EN: Purpose. In this paper it is necessary to conduct: 1) research and analyse the influence of throttle element pneumatic resistance on elastic and damping parameters of air spring; 2) to obtain the dependence of air spring parameters on throttle element pneumatic resistance value. Methodology. The work presents the elaborated model of the air spring as a dynamic system with three phase coordinates (cylinder pressure, auxiliary reservoir pressure, cylinder air mass). Stiffness and viscosity coefficients were determined on the basis of system response to harmonic kinematic disturbance. The data for the analysis are obtained by changing the capacity of the connecting element and the law of pressure variation between the reservoir and the cylinder. The viscosity coefficient is regarded as the viscosity ratio of the hydraulic damper, which for one oscillation cycle consumes the same energy as the air spring. The process of air condition change inside the cylinder (reservoir) is considered to be adiabatic; the mass air flow through the connecting element depends on the pressure difference. Findings. We obtained the curves for spring viscosity and stiffness coefficients dependence on the throttle resistance at three different laws, linking airflow through the cylinder with the pressure difference in cylinder and reservoir. At both maximum and minimum limiting resistance values the spring viscosity tends to zero, reaching its peak in the mean resistance values. Stiffness increases monotonically with increasing resistance, tends to the limit corresponding to the absence of an auxiliary reservoir (at high resistance) and the increase in cylinder volume by the reservoir volume (at low resistance). Originality. The designed scheme allows determining the optimal parameters of elastic and damping properties of the pneumatic system as function of the throttle element air resistance. Practical value. The ability to predict the parameters of elastic and damping properties of the pneumatic system as function of the throttle element air resistance will improve the running performance of carriages, the comfort of passenger transportation and reduce the wear of the rolling stock and the track caused by interaction of carriage and rails.Item Determination of Stopping Distance of Unpowered Rolling Stock by Method of Sequential Braking(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Reidemeister, Alexey G.; Shaposhnyk, Vladyslav Yu.EN: Purpose. In the paper it is necessary to estimate the determination accuracy of a car stopping distance during the test by the method of sequential braking. The method of sequential braking is applied for experimental evaluation of the stopping distances. Unlike the abandonment method when a sample car is disconnected from the tractive connection and they record the stopping distance of a single car from the moment of uncoupling to the moment of stop, the method of sequential braking involves stopping distance measurement of the tractive connection, the integrity of which in the course of the test is not affected, but its set (locomotive, locomotive with the track test car or with a sample car) at the different stages of the test is changed. Direct measuring of the stopping distance of a sample car is not possible using this way, it requires calculating of the stopping distance values of the tractive connection. This adversely affects the accuracy of the result, but it can increase the safety level of the test. Methodology. To evaluate the accuracy researches have conducted the numerical experiment, which simulated experimental processing of stopping distance values. An error was found by giving disturbance of basic data (stopping distance of tractive connection of different configuration) and analyzing the resulted scatter of readings (stopping distance of a single car). Findings. The study proved: 1) the relative error of car stopping distances value, with relative error of basic data 1%, made 3.3-19.7% (depending on the tractive connection variant). 2) the proposed ways of error reduction (without track test car, less-weighed-locomotive use) allowed declining the error to 2.15-5.1%. Originality. The methodology of error estimation of car stopping distances determination under tests by the method of sequential braking was proposed. Practical value. Work results make it possible to replace the running brake tests by the abandonment method, under which the integrity of tractive connections is broken, with safer testing by the method of sequential braking, providing the level of result accuracy of 2-5%.Item Determining the Possibility of Using Removable Equipment for Transporting 20- and 40-Feet-Long Containers on an Universal Platform Wagon(Technology Center, Kharkov, Ukraine, 2021) Shaposhnyk, Vladyslav Yu.; Shykunov, Oleksandr A.; Reidemeister, Alexey G.; Muradian, Leontii A.; Potapenko, O.EN: An important role in the market of transport services belongs to container transportation. Railroads, especially under the conditions of increased competition from road transport, must respond quickly to the needs of the market and the growing demand for container transportation, including interstate traffic. Demand for container transportation can vary significantly during the year, which testifies to the expediency of introducing removable equipment on universal railroad freight cars that are involved in the deliveries of containers. This paper reports the design of a removable frame structure for a universal platform that could carry two 20-ft or one 40-ft container. The proposed technical solution does not require changes in the structure of the car and changes in its model; with a decrease in the demand for container transportation, it would allow this car to be used for its main purpose. According to the current methodology, the efforts that operate on the frame during the transportation of containers have been determined. The strength of the proposed structure was estimated by a finite-element method. The maximum stresses arising in the proposed structure are 164.4 MPa; they occur in the corners of the stops attached to the stand-up staples of the platform. The resulting stress values do not exceed the allowable ones. The results of calculating the removable equipment indicate its sufficient strength. Requirements for placing cargo on the rolling stock assume a mandatory check to fit the dimensions, which confirmed that the container hosted by the frame does fit them. The proposed structure makes it possible to abandon disposable fastening parts, improve the safety of container transportation, and increase competitiveness in the container transportation market.Item Development of Recommendations for Extending the Useful life of Passenger Cars(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Myamlin, Serhiy V.; Reidemeister, Alexey G.; Pulariia, Andriy L.; Kalashnyk, Volodymyr O.EN: Purpose. The vast majority of passenger car fleet of «Ukrzaliznytsia» have cars with outlasted service life. In this regard there is a need to find methods to justify the extending useful life of passenger cars and to assess the car body frame residual life conformity to the operating load for the next life time. Methodology. The selection of cars enforced technical diagnostics of cars to detect the level of corrosion and mechanical damage. The following steps provided the car body frame strength analysis on the basis of experimental static and impact strength tests, the longitudinal force effect endurance tests as well as assessment and forecasting of conformity of car body operating life for the next period. Findings The car survey before testing showed that the technical condition of sleeper cars (SSC) is better than that of open-type cars (SOC). So, in SSC cars the thinning of the main load-bearing elements due to corrosion does not exceed 10%, there are no cracks, deformations, rack breakages, etc. At the same time in SOC cars the thinning due to local corrosion reached 35%. There are deformations and corrosion damage of side sill Zshape of both cars, single corner post breakages, damage to the joints of longitudinal tie rod and span bolsters. The conducted static and impact strength tests with following strength assessment of the car structural members showed that the strength of the latter is provided according to the normative documents, and these cars pose no threat to traffic safety. The impact endurance tests showed that all the cars passed the endurance tests without damage, which would prevent from testing and could not be removed during the next depot repair or overhaul, and had life length that allows them to extend the useful life for the next period. Originality. The results of experimental studies show that passenger cars after 28 … 30 and 33… 35 years of operation meet the requirements of strength and safety in accordance with regulatory documents and allow, provided the impact endurance, reasonable extending of the car service life. Practical value. The part of the car fleet, which was to be written off based on the service life, may extend lifespan without additional measures.Item Improvement of the Open Wagon for Cargoes which Imply Loading with a "Hat"(IOP Publishing, 2020) Reidemeister, Alexey G.; Muradian, Leontii A.; Shaposhnyk, Vladyslav Yu.; Shykunov, Oleksandr A.; Kyryl’chuk, Oleg A.; Kalashnyk, Volodymyr O.EN: The goal of the article is to evaluate the possibility of improving the design of an open wagon body in order to improve traffic safety when transporting cargoes whose height is beyond the upper belt of the side wall (cargo loading with a “hat”). To achieve it, the authors have proposed a variant of a pull-out bar in a wall rack. In lazy state such bars located inside racks, but during transportation of timber, pipes etc they are pulled out above the wall upper belt to prevent cargo from rolling out. These bars are quite light (mass of one pull-out bar is equal to 3 kg, that corresponds to 36 kg of an additional equipment per a wagon), but they considerably facilitate fixing cargo in an open wagon replacing additional wooden fixing racks. It also makes the transportation more reliable due to elimitation the possibility of skew and jamming of fixing equipment. Strength of the proposed element and the entire wagon side wall is estimated with the finite element method. The proposed bars withstand normative loads, and holes in the upper belt for them do not lead to desrease of the wall carrying capacity.Item Investigation of Possibility of Hopper Cars Unloading on the Car Dumper VRS–134M(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Dovhaniuk, Stepan S.; Kalashnyk, Volodymyr O.; Reidemeister, Alexey G.; Shykunov, Oleksandr A.EN: Abstract. It was developed a computational model to evaluate the body strength of short base hopper models 19-758-01, 20-471, and 20-4015 when unloading them on the car dumper VRS–134M. Modeling of the stress-strain state of the car design was made using the finite element method. It was established that in terms of strength, bodies of the hopper models 19-758-01, 20-471, and 20-4015 are suitable for unloading on car dumper. The results of experimental studies showed sufficiently high accuracy of the chosen computational model for estimating the stress-strain state of design and confirmed the possibility of hopper car unloading on the car dumper VRS–134M.Item Modernization as a Way to Improve the Use of Universal Cars(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Reidemeister, Alexey G.; Kalashnyk, Volodymyr O.; Shykunov, Oleksandr A.EN: Purpose. The main design requirements of the modernized cars are those allowing reduction of operating costs and improvement of economic efficiency of their use. Due to the relevance of this subject the work presents the complex of conducted research, which will allow in prospect to use the universal flatcar, converted according to the Technical specifications TU 3182-065-71390252-2911 for container service. The research includes: evaluation of strength, fatigue safety of the design elements and conformity assessment of the strength characteristics of the modernized flatcar elements to the regulatory documents. Methodology. The analysis covers the use of specialized and universal rolling stock for transportation of containers, as well as the issues of modernization of universal cars. The strength of the flatcar bearing structure is evaluated based on the complex of numerical and experimental studies. The experimental part includes the static, repair load and impact tests. The car strength qualities and the fatigue safety are evaluated on the basis of calculated and experimental data. Findings. The conducted static, repair load and impact tests, given the quasi-static longitudinal forces, allowed the evaluation of the car structure strength according to the regulatory documents. The calculated and experimental data make it possible to assess the fatigue safety of structural elements. The present work is completed by obtaining the results that allow performing reasonable re-equipment of universal flatcars with baseplates with fitting stops to fasten the containers. Originality. The results of calculated and experimental studies showed that the modernized flatcars meet the conditions of strength and have sufficient fatigue safety factor. This makes it possible to recommend the re-equipment of universal flatcars for all car-repair enterprises that submitted the prototypes. Practical value. The complex of works was conducted that demonstrated the possibility of re-equipment of universal flatcars for the transportation of large containers. Part of the car fleet, kept in reserve, with little material costs can be transferred to the operational fleet. The modernization – re-equipment of universal flatcars with stationary specialized devices will increase the car usability coefficient.Item Sensitivity of Stresses to the Forces Acting on the Cast Parts of Freight-Car Bogie(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Reidemeister, Alexey G.; Shykunov, Oleksandr A.EN: Purpose. To determine the effect of the force components acting in the axle box and the central spring suspension on the stresses occurring in the side frame of the three-piece bogie. Methodology. To assess the effect of the forces acting on the side frame on the stresses in it, we developed a finite element model of the side frame. After that, we carried out an assessment of its stress-strain state under loading conditions corresponding to the І and ІІІ design modes. According to the results obtained, we determined the stress concentration points in the construction, which are selected as check ones for further studies. Also, as checkpoints we took the points corresponding to the sensor locations when estimating the stresses in the side frame during the tests. At the next stage, we applied unit loads in sequence at the interaction points of the side frame with the boxes and the central spring group. To obtain a more accurate result, the unit forces were balanced by the corresponding forces and moments of inertia. With each loading variant, tensors of stresses arising from the action of unit loads were obtained at checkpoints. On the basis of the stress tensors obtained, we determined the corresponding equivalent stresses – the sensitivity coefficients. Findings. The paper determines the stress sensitivity coefficients in the three-piece bogie side frame to external loads acting on the side frame from the side of axle box and central spring group. Based on the results of the assessment of the coefficients obtained, we determined the forces having the greatest influence on individual sections of the side frame. We estimated the possibility of using the obtained results in optimizing the parameters of the bogie spring suspension to increase the strength and durability of the side frame. Originality. For the first time, the effect of individual components of the forces acting on the side frame on the stresses in it has been estimated. Practical value. The obtained result can be used in the design and optimization of three-piece bogies, to improve the side frame durability. The stress tensors obtained can be used to estimate the effect of complex loading on the side frame strength and durability.Item Stability of Motion of Railway Vehicles Described with Lagrange Equations of the First Kind(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Reidemeister, Alexey G.; Levytska, Svitlana І.EN: Purpose. The article aims to estimate the stability of the railway vehicle motion, whose oscillations are described by Lagrange equations of the first kind under the assumption that there are no nonlinearities with discontinuities of the righthand sides. Methodology. The study is based on the Lyapunov’s stability method of linear approximation. The equations of motion are compiled in a matrix form. The creep forces are calculated in accordance with the Kalker linear theory. Sequential differentiations of the constraint equations reduced the equation system index from 2 to 0. The coefficient matrix eigenvalues of the system obtained in such a way are found by means of the QR-algorithm. In accordance with Lyapunov's criterion of stability in the linear approximation, the motion is stable if the real part of all eigenvalues is negative. The presence of «superfluous» degrees of freedom, which the mechanical system does not have (in whose motion equations there are left only independent coordinates) is not trivial. Herewith the eigenvalues and eigenvectors correspond to these degrees of freedom and have no relation to the stability. In order to find a rule that allows excluding them, we considered several models of a bogie, with rigid and elastic constraints of high rigidity at the nodes. In the limiting case of high rigidities, the results for a system without rigid constraints must coincide with the results for a system with rigid constraints. Findings. We carried out the analysis and compared the frequencies (with decrements) and the vibration modes of a threepiece bogie with and without constraints. When analysing the stability of the system with constraints, only those eigenvalues are of interest whose eigenvectors do not break the constraints. The values of these numbers are limits for the eigenvalues of the system, in which rigid constraints are replaced by elastic elements of high rigidity, which allows us to leave the Lyapunov’s criterion unchanged. Originality consists in the adaptation of Lyapunov's stability method of linear approximation to the case when the equations of railway vehicle motion are written in the form of differential-algebraic Lagrange equations of the first kind. Practical value. This written form of the equation of motion makes it possible to simplify the stability study by avoiding the selection of a set of independent generalized coordinates with the subsequent elimination of dependent ones and allows for the coefficient matrix calculation in an easily algorithmized way. Information on the vehicle stability is vitally important, since the truck design must necessarily exclude the loss of stability in the operational speed range.