Browsing by Author "Kalivoda, Jan"
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Item Changing the Stress State of the Track Superstructure while Strengthening the Subgrade(VŠB – Technical University of Ostrava, 2020) Tiutkin, Oleksii L.; Neduzha, Larysa O.; Kalivoda, JanENG: Strengthening the subgrade with the help of various technologies significantly affects the stress state of the track superstructure. The strengthening of the subgrade with piles, leads to an abrupt stiffening of the track superstructure, which is problematic for its normal operation. Two finite element models were created to determine the change in the stress state of the track superstructure when strengthening the subgrade. They fully reflect the geometric, deformation and power characteristics of a real subgrade, which is strengthened by piles. Individual finite elements of the models are provided with the deformation characteristics of the steel rails, reinforced concrete sleepers, soil subgrade, ballast and soil-cement material of piles. The authors carried out the calculation of stress state of the track superstructure for two finite element models. Results are obtained and analyzed to help in choosing the most effective option for strengthening the subgrade.Item Enhancing the Scientific Level of Engineering Training of Railway Transport Professionals(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Kalivoda, Jan; Neduzha, Larysa O.EN: Purpose. Publication of the results of international scientific and technical cooperation of the Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan (DNURT, Ukraine) and the Czech Technical University (CTU) in the field of engineering training of students on the basis of modern methods of development of scientific and creative abilities of students. Methodology. The development of scientific thought and the improvement of the professional level of students of engineering specialties of railway technical institutes may be carried out by different methods both during training and during extracurricular time. One of the methods for improving the scientific level of future engineers is the public lectures of renowned scholars and researchers from leading European higher education institutions, enabling students to have access to world-class advanced scientific idea. Findings. The authors have analyzed the activity of DNURT and CTU on scientific and educational preparation of students. It is emphasized that cooperation promotes strengthening of contacts between universities, improves the quality of students' training, is one of the factors of the professional development of future specialists, raising the scientific level of engineering training of railway transport professionals. It is proved that DNURT and CTU duly fulfill the higher education tasks of training of professional personnel who are able to work effectively in the global market, aimed at improving the quality and efficiency of education. Originality. This paper presents the analysis of results concerning the efficiency of application of modern methods for engineering training of students of technical higher educational institutions. It gives extended view of the main directions of international education activities. Practical value. It is confirmed that popularization of modern methods of propagation of engineering thought among student youth has acquired a new meaning and contributes to enhancing the scientific level of engineering training of railway transport professionals.Item Finite-Element Analysis of Strengthening the Subgrade on the Basis of Boring and Mixing Technology(The Silesian University of Technology, 2021) Tiutkin, Oleksii L.; Neduzha, Larysa O.; Kalivoda, JanENG: One of the effective techniques to strengthen the subgrade is boring and mixing technology, which is based on the immersion of vertical elements – piles into the subgrade. This method of strengthening significantly affects the stress state of the track superstructure. Two options of the placement of strengthening elements are examined in this paper. To determine the influence of position of strengthening elements on the stress state of the track superstructure, appropriate finite-element models were created. The models fully reflect the geometric and deformation characteristics of a real subgrade, which is strengthened by piles. The calculated stress state of the track superstructure is shown and analyzed in this paper. The main contribution of the paper lies in optimization of the geometric parameters of the technology to reduce the stress state of the "track superstructure–subgrade–soil basement" system. The results show that the location of piles near the rails is more effective than the location of piles near the ballast section.Item High Speed Stability of a Railway Vehicle Equipped with Independently Rotating Wheels(Ústav Teoretické a Aplikované Mechaniky, Prosecká, Czech Republic, 2018) Kyryl’chuk, Oleg A.; Kalivoda, Jan; Neduzha, Larysa O.EN: The paper is devoted to the study of lateral oscillation and the assessment of the motion stability of a four axle railway vehicle equipped with wheelsets with independently rotating wheels. First, a linear four degrees of freedom mathematical model of the unconstrained wheelset in a straight track has been built. The wheelset model was consequently utilized in a model of the whole vehicle representing typical railway passenger car. The model has 25 degrees of freedom and it is described by a system of 50 first order homogeneous differential equations. Linear algebra methods were used to assess the stability. The influence of a running velocity, the torsional stiffness of wheelsets and the viscosity of coupling element between wheels was studied. Results of this study shows that wheelsets with independently rotating wheels and viscous coupling element enable stable behaviour of a vehicle at speeds exceeding 500 km/h. Prospectively, this type of wheelset is applicable to high-speed railway vehicles, because it offers either further increase of running speeds or simplification of running gear while preserving high speed stability.Item High Speed Stability of a Railway Vehicle Equipped with Independently Rotating Wheels (preprint)(Ústav Teoretické a Aplikované Mechaniky, Prosecká, Czech Republic, 2018) Kyryl’chuk, Oleg A.; Kalivoda, Jan; Neduzha, Larysa O.EN: The paper is devoted to the study of lateral oscillation and the assessment of the motion stability of a four axle railway vehicle equipped with wheelsets with independently rotating wheels. First, a linear four degrees of freedom mathematical model of the unconstrained wheelset in a straight track has been built. The wheelset model was consequently utilized in a model of the whole vehicle representing typical railway passenger car. The model has 25 degrees of freedom and it is described by a system of 50 first order homogeneous differential equations. Linear algebra methods were used to assess the stability. The influence of a running velocity, the torsional stiffness of wheelsets and the viscosity of coupling element between wheels was studied. Results of this study shows that wheelsets with independently rotating wheels and viscous coupling element enable stable behaviour of a vehicle at speeds exceeding 500 km/h. Prospectively, this type of wheelset is applicable to high-speed railway vehicles, because it offers either further increase of running speeds or simplification of running gear while preserving high speed stability.Item Influence of Parameters of Electric Locomotive on its Critical Speed(Springer, Cham, 2020) Klimenko, Irina V.; Kalivoda, Jan; Neduzha, Larysa O.EN: Abstract. A high speed is one of the most important todays requirements for the rail transport. However, increasing the maximum speed brings also the problem of a vehicle stability. The parameters of the vehicle suspension should be tuned in order to achieve vehicle stability in the entire speed range. The article presents the results of theoretical study of the impact of the suspension parameters of the mainline electric locomotive type DS3 on the magnitude of its critical speed. The stability and critical speed are assessed by eigenvalues calculation of the linear model of the vehicle. The study compares 9 variants of vehicle parameters. The sensitivity of the critical speed on the individual parameters is shown and discussed. At the same time, it is shown that by tuning vehicle parameters in order to achieve high critical speed, some other vehicle characteristics may deteriorate. As the result, the optimal range of the stiffness values of the connection of axle-boxes and bogie-frame is recommended.Item Parameter Optimization of the Locomotive Running Gear(Kaunas University of Technology, Kaunas, Lithuania, 2018) Klimenko, Irina V.; Kalivoda, Jan; Neduzha, Larysa O.EN: In principle all railway vehicles exhibit lateral oscillations, also called a hunting motion. Stability of hunting motion usually decreases with increasing running velocity and the speed at which hunting motion becomes unstable limits the maximal permissible speed of railway vehicle. When designing a new rolling stock, it is necessary to tune the parameters of a vehicle suspension so that the critical velocity is higher than the maximum operational vehicle speed. In the paper the Nelder-Mead optimization is proposed as the method useful for finding the optimal vehicle parameters at which the maximum critical velocity is reached. This optimization method was applied to the locomotive DS3. The results are presented and discussed in the paper.Item Running Dynamics of Rail Vehicles(MDPI, Basel, Switzerland, 2022) Kalivoda, Jan; Neduzha, LarysaENG: The investigation of rail vehicle running dynamics plays an important role in the more than 200 year development of railway vehicles and infrastructure. Currently, there are a number of new requirements for rail transport associated with the reduced environmental impact, energy consumption and wear, whilst increasing train speed and passenger comfort. Therefore, the running dynamics of rail vehicles is still a research topic that requires improved simulation tools and experimental procedures.Item Running Dynamics of Rail Vehicles (book)(MDPI, Basel, Switzerland, 2022) Neduzha, Larysa; Kalivoda, JanENG: The investigation of rail vehicle running dynamics plays an important role in the more than 200 year development of railway vehicles and infrastructure. Currently, there are a number of new requirements for rail transport associated with the reduced environmental impact, energy consumption and wear, whilst increasing train speed and passenger comfort. Therefore, the running dynamics of rail vehicles is still a research topic that requires improved simulation tools and experimental procedures.Item Simulating the Operation of the Pantograph-type Current Collector(KTU leidykla „Technologija“, Kaunas, Lithuania, 2022) Babyak, Mykola O.; Kalivoda, Jan; Neduzha, LarysaENG: The usage of electricity to increase the safety and environmental friendliness of transportation is a very important issue. The common feature in the work of different types of electric transport is the dependence on reliable contact with the conductor from which it receives power. The reliability of the constant movable contact between the conductor with current and electrical equipment depends on the precise operation of the pantograph complex mechanism. To simplify the planning calculations and approbation of structures, a pantograph model with two degrees of freedom is proposed. It gives an adequate description of the real system and improves the mathematical apparatus while calculating the forces and dynamic displacements of the pantograph mechanisms for electric transport.Item Simulation of Safety Against Derailment Tests of an Electric Locomotive(Ústav Teoretické a Aplikované Mechaniky, Prosecká, Czech Republic, 2019) Kalivoda, Jan; Neduzha, Larysa O.EN: Abstract: European standards define the conditions for stationary and track tests that each new type of rolling stock has to pass within its approval process. Because those tests are demanding and their results are influenced by weather conditions and other random factors, there is an attempt to replace them by computer simulations. The paper deals with simulations of stationary tests for proving safety against derailment. The multibody simulation model of Ukrainian electric locomotive DS3 has been built. This model was used to simulate all three methods defined in the European standard EN 14363 for proving safety against derailment. The results of the simulations are shown in the paper.Item Testing of Railway Vehicles Using Roller Rigs(Vilnius Gediminas Technical University, Vilnius, Lithuania, 2017) Myamlin, Sergey V.; Kalivoda, Jan; Neduzha, Larysa O.EN: Roller rigs are laboratory devices enabling to study various phenomena in the field of railway vehicles dynamics and the wheelrail contact. The main benefits of roller rig experiments are high controllability, repeatability and flexibility of experiment setup and usually also lower costs compared to the field tests. One of the goals of joint cooperation between the Czech Technical University in Prague, Czech Republic (CTU) and the Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Ukraine (DNURT) is to design, build, and finally to operate at the DNURT laboratory the new roller rig. The presented paper is an initial study prepared within the framework the joint project. It summarizes the possibilities of roller rig utilization for railway vehicles research and describes the main concepts of existing design solutions.