CRUST | Browsing by Author "Kovalchuk, Vitalii V."

Browsing by Author "Kovalchuk, Vitalii V."

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Common Crossing Condition Monitoring with on-Board Inertial Measurements
(Czech Technical University, Prague, 2019) Sysyn, Mykola; Nabochenko, Olga; Gerber, Ulf; Kovalchuk, Vitalii V.; Petrenko, Oleksiy
EN: A railway turnout is an element of the railway infrastructure that influences the reliability of a railway traffic operation the most. The growing necessity for the reliability and availability in the railway transportation promotes a wide use of condition monitoring systems. These systems are typically based on the measurement of the dynamic response during operation. The inertial dynamic response measurement with on-board systems is the simplest and reliable way of monitoring the railway infrastructure. However, the new possibilities of condition monitoring are faced with new challenges of the measured information utilization. The paper deals with the condition monitoring of the most critical part of turnouts - the common crossing. The application of an on-board inertial measurement system ESAH-F for a crossing condition monitoring is presented and explained. The inertial measurements are characterized with the low correlation of maximal vertical accelerations to the lifetime. The data mining approach is used to recover the latent relations in the measurement’s information. An additional time domain and spectral feature sets are extracted from axle-box acceleration signals. The popular spectral kurtosis features are used additionally to the wavelet ones. The feature monotonicity ranking is carried out to select the most suited features for the condition indicator. The most significant features are fused in a one condition indicator with a principal component analysis. The proposed condition indicator delivers an almost two-time higher correlation to the lifetime as the maximal vertical accelerations. The regression analysis of the indicator to the lifetime with an exponential fit proves its good applicability for the crossing residual useful life prognosis.
Common Crossing Fault Prediction with Track Based Inertial Measurements: Statistical vs. Mechanical Approach
(Akadémiai Kiadó, Hungary, 2019) Sysyn, Mykola; Gerber, Ulf; Nabochenko, Olga; Kovalchuk, Vitalii V.
EN: The analysis of track based inertial measurements for common crossing fault detection and prediction is presented in the paper. The measurement of spatial acceleration in common crossing spike and impact position during overall lifecycle are studied regarding to rolling surface fatigue degradation. Two approaches for retrieving the relation of inertial parameters to common crossing lifetime are proposed. The first one is based on the statistical learning method - t-SNE algorithm that helps to find out similarities in measured dataset. The second one is a mechanical approach that handles the data with a fatigue and contact models. Both approaches allow the significant improvement of the common crossing fault detection as well as its early prediction.
Common Crossing Structural Health Analysis with Track-Side Monitoring
(EDIS, University of Zilina, Slovakia, 2019) Sysyn, Mykola P.; Nabochenko, Olga S.; Kluge, Franziska; Kovalchuk, Vitalii V.; Pentsak, Andriy
EN: Track-side inertial measurements on common crossings are the object of the present study. The paper deals with the problem of mea- surement's interpretation for the estimation of the crossing structural health. The problem is manifested by the weak relation of measured acceleration components and impact lateral distribution to the lifecycle of common crossing rolling surface. The popular signal processing and machine learning methods are explored to solve the problem. The Hilbert-Huang Transform (HHT) method is used to extract the time-frequency features of acceleration components. The method is based on Ensemble Empirical Mode Decomposition (EEMD) that is advantageous to the conventional spectral analysis methods with higher frequency resolution and managing nonstationary nonlinear signals. Linear regression and Gaussian Process Regression are used to fuse the extracted features in one structural health (SH) indicator and study its relation to the crossing lifetime. The results have shown the significant relation of the derived with GPR indicator to the lifetime.
Comparative Calculation of the Stability of the Landslide Slope in the Software Complexes «OTKOS» and «LIRA-CAD 2017»
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2018) Petrenko, Volodymyr D.; Tiutkin, Oleksii L.; Ihnatenko, Dmytro Yu.; Kovalchuk, Vitalii V.
ENG: Purpose. The analysis and comparison of the results of calculation by the finite-element model of the slope in the software complex «LIRA-CAD 2017» with the determination of the its stability in the software complex «OTKOS» allows to determine the accuracy the results and the most favorable conditions for the development of the displacement and parameters of the most dangerous surface slip for further calculation of anti-slip retaining structures. Methodology. The geomorphological data were obtained from the results of laboratory studies of soils in the considered slope. Creation of a bulk finite element model of the slope in accordance with the built cuts and depths of soil layers. Calculation of the nonlinear problem of finite-element simulation of the slope in the software complex «LIRA-CAD 2017». Creation and calculation of the stability problem of the landslide slope in the software complex «OTKOS» and comparison of the results of the its stress-strain state. Results. The results of calculating the finite-element model of the landslide slope in the software complex «LIRA-CAD 2017» and its stability in the software complex «OTKOS» were obtained. The analysis of the obtained results of sliding surfaces study is carried out. The calculation of the strengthening of the slope area is carried out with the help of soil cement retaining piles, located at right angles to the vector of the displacement direction. Originality. Despite the presence of a large number of different methods of studying the surfaces of sliding, it is impossible to determine exactly the scenario of the displacement, using only one of the calculation methods. First of all, this is due to the rather high variation of the initial data of the problem, which in turn depends on the environment and assumptions, as well as on external factors that can not be taken into account precisely. The next task is to carry out the calculation of the strengthening of the landslide slope by soil-cement piles. Practical value. It is known that it is advisable to use soil-cement piles as a protective element, which interacts well with the soil environment due to its structure of the source material. A comparative analysis of the calculation results of the slope stability with the help of software systems «LIRA-CAD 2017» and «OTKOS» gives an answer to the question of the its reliability.
Comparison of the Effects and Efficiency of Vertical and Side Tamping Methods for Ballasted Railway Tracks
(Elsevier Ltd, 2022) Przybyłowicz, Michał; Sysyn, Mykola; Gerber, Ulf; Kovalchuk, Vitalii V.; Fischer, Szabolcs
EN: The relatively high maintenance costs of the ballast track are related to the short lifecycle of the ballast layer. The current vertical ballast tamping technology (e.g., Plasser & Theurer, Matisa, etc.) causes high ballast destruction and is neither applicable for unconventional sleepers’ designs nor slab tracks. The side tamping method presents an alternative, ballast saving, and sleeper form independent ballast tamping technology. This paper compares the ballast layer compaction and its resistance to permanent settlements accumulation after the vertical and the side tamping methodologies. Scaled models of ballast layer and tamping units and scaled simulation with discrete element method (DEM) were applied for the comparison. In the laboratory tests, the ballast compaction along the sleeper was estimated using the measurements of elastic wave propagation. The settlements resistance for both tamping methods was estimated under the vibration loading. The tests’ results show 5–7% higher compactness of the ballast layer under the sleeper ends for the side tamping method. The settlement intensity of the ballast layer after the vertical tamping is higher than for the side tamping method. In discrete element modeling, the performed laboratory tests were simulated. The compactness of the ballast bed, as well as the residual stresses, were determined in MATLAB. The side tamping technology provided five times higher residual stresses in the ballast layer below the sleeper than in the case of vertical tamping, which can be explained by the more stable and dense layer resulting from the side tamping ensures higher interlocking between the grains. The simulation of the wave propagation shows an influence of the residual stresses on the wave propagation velocities. The simulated wave propagation velocity was more than two times higher for the side tamping than for the vertical one.
The Complex Phenomenological Model for Prediction of Inhomogeneous Deformations of Railway Ballast Layer after Tamping Works
(Warsaw University of Technology, Poland, 2018) Sysyn, Mykola P.; Gerber, Ulf; Kovalchuk, Vitalii V.; Nabochenko, Olga S.
EN: The given article considers the method of calculating the track geometry deformation with respect to uneven accumulation of residual deformations along the track. The technique proposes two significant changes in existing approaches to calculating the efficiency of the ballast layer. The transition from the approach of allowable stresses design in the ballast layer to the deformative approach of accumulations of track geometry deformations allows us to draw conclusions regarding the intervals of track tamping and the duration of ballast layer life cycle. The transition from the determinative to probabilistic approaches makes it possible to draw conclusions not only from the average unevenness, but also with regard to all possible facts of unevenness. The method is based on the mechanism of sudden and gradual deformations occurrence, which depends on a number of key factors: dynamic stresses on the ballast, non-uniformity of track elasticity, performance of current maintenance work. Based on the experimental studies results, the dependencies of sudden deformations and the intensity of gradual deformations on the level of stress on the ballast layer were established. The experimental results of the influence of the sub-ballast base elasticity on the intensity of accumulation of residual deformations are shown. On the basis of the developed method, the prediction of track geometry deterioration for a given structure of the track, the rolling stock and the permissible level of geometric deviations for track maintenance is presented.
A Comprehensive Procedure for Estimating the Stressedstrained State of a Reinforced Concrete Bridge Under the Action of Variable Environmental Temperatures
(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, Ukraine, 2021) Kovalchuk, Vitalii V.; Onyshchenko, Artur; Fedorenko, Olexander; Habrel, Mykola; Parneta, Bogdan Z.; Voznyak, Oleh M.; Markul, Ruslan V.; Parneta, Mariana; Rybak, Roman
ENG: This paper reports the full-scale experimental measurements of temperature distribution over the surfaces of bridges’ steel-concrete beams under the influence of positive and negative ambient temperatures. It has been established that the temperature is distributed unevenly along the vertical direction of a bridge’s steel-concrete beam. It was found that the metal beam accepted higher temperature values. The maximum registered temperature difference between a metal beam and a reinforced concrete slab at positive ambient temperatures was +9.0 °C, and the minimum temperature difference was −2.1 °C. The mathematical models for calculating a temperature field and a thermally strained state of bridges’ steel-concrete beams under the influence of variable climatic temperature changes in the environment have been improved, taking into consideration the uneven temperature distribution across a bridge’s reinforced concrete beam. The possibility has been established to consider a one-dimensional problem or to apply the three-dimensional estimated problem schemes as the estimation schemes for determining the thermoelastic state of reinforced concrete bridges. The temperature field and the stressed state of bridges’ reinforced concrete beams were determined. It was found that the maximum stresses arise at the place where a metal beam meets a reinforced concrete slab. These stresses amount to 73.4 MPa at positive ambient temperatures, and 69.3 MPa at negative ambient temperatures. The amount of stresses is up to 35 % of the permissible stress values. The overall stressed-strained state of a bridge’s reinforced concrete beams should be assessed at the joint action of temperature-in- duced climatic influences and loads from moving vehicles.
Cracks Interaction in the Elastic Composite under Action of the Harmonic Loading Field
(Tbilisi State University, Georgia, 2018) Stankevych, Volodymyr Z.; Butrak, I. O.; Kovalchuk, Vitalii V.
EN: A three-layer composite with penny-shaped cracks in the field of harmonic torsional loading is considered. The solutions are chosen in the form of Helmholtz potentials with densities that characterize unknown crack opening functions. The problem is reduced to the solution of the system of two-dimensional boundary integral equations (BIFs). The influence of the frequency of the applied load, the ratio of the elastic constant parameters of the composite on the dynamic stress intensity factors in the defect vicinity is investigated.
Degradating Concrete and Reinforced Concrete Building Structures and Long-Term Structures
(Одеська державна академія будівництва та архітектури, 2022) Luchko, Joseph; Nazarevich, B.; Kovalchuk, Vitalii V.
ENG: In the work on the basis of the performed field researches the problems of degradation of concrete and reinforced concrete constructions of buildings and constructions of long operation are formulated and its urgency is noted. The authors analyzed a number of works on this problem. In particular, the results of technical diagnostics of many buildings and structures, both newly built and long-term operation, are described. The necessity of periodic technical diagnostics is noted. Based on these studies, the main factors that significantly affect the reduction of load-bearing capacity of reinforced concrete structures of buildings and structures are summarized and found that they are as follows: design errors, defects and shortcomings of construction and operational shortcomings of buildings and structures. Also, using modern technologies and materials, the authors identified the benefits of their use for repair and restoration of concrete and reinforced concrete structures at a number of long-term facilities. Relevant conclusions have been formulated on research and repair works. It is established that to prevent loss of load-bearing capacity of structures for long-term operation it is necessary to study the degradation and residual life of load-bearing capacity of structures, their reliability and durability, which were exposed to aggressive air, soil and water. It is established that the reason for the decrease in the strength of concrete beams, which were operated in an aggressive environment, was the error in the design of corrosion protection of structures. Reinforcement and injection filling of dry cracks, crevices and hidden cavities and stratifications and other corrosion damage of beams and slabs with the use of fluid polyurethane compositions, which allowed to extend the service life of structures. It is established that the use of the Polymer Cement Concrete system with the use of glued composite materials ensured the further normal operation of the monolithic reinforced concrete floor of the technical floor of the residential building. Recommendations for the sequence of operations in the repair of reinforced concrete structures of buildings and structures of long-term operation.
Determining Patterns in the Stressed-Deformed State of the Railroad Track Subgrade Reinforced with Tubular Drains
(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, Ukraine, 2020) Luchko, Josyp; Kovalchuk, Vitalii V.; Kravets, Ivan B.; Gajda, Oleksiy; Onyshchenko, Artur
EN: The technical condition of the railroad track subgrade has been analyzed, as well as the issues related to ensuring its strength and stability when exposed to floodwaters and when the track's sections are overmoistened during operation. As a result, it has been established that it is necessary to develop methods aimed at improving the subgrade's carrying capacity. The georadar research has explored the problematic areas of the railroad track subgrade, based on which the distribution of subgrade heterogeneity in the vertical plane, as well as the boundaries of its location, were established. Therefore, georadar research makes it possible to detect hidden defective sites in the subgrade without disrupting its strength characteristics. A technique has been proposed to improve the carrying capacity of the failed subgrade of a railroad track using the combined arrangement of drainage pipes in the vertical and horizontal directions in the railroad embankment. The special feature of this technique is the possibility to drain water at the different levels of surface water, which provides for an increase in the carrying capacity of the failed subgrade. The strained-deformed state of the subgrade reinforced with tubular drainage has been investigated. The result has proven the effectiveness of the use of tubular drainages to improve the carrying capacity of the railroad track overmoistened subgrade exposed to constant and temporary loads. This study findings have established that the deformity of the subgrade increases when using tubular drainage, though this occurs only in the initial period of its arrangement, in further operation, when it removes water from the subgrade body, the carrying capacity of the subgrade, on the contrary, will improve due to the enhanced physical and mechanical properties of soils.
Determining the Dynamic Indicators of the Pneumatic Spring for High-Speed Rolling Stock in the Zone of a Rail Joint along a Railroad Track
(TECHNOLOGY CENTER PC, Kharkiv, 2024) Kovalchuk, Vitalii V.; Kuzyshyn, Andriy Ya.; Royko, Yuriy; Hermaniuk, Yuliia M.; Tereshchak, Yuriy V.; Pulariia, Andriy L.
ENG: The object of this study is the pneumatic spring of the high-speed railroad rolling stock that moves over the rail joint of a railroad track with a vertical ledge. The task solved was establishing the dynamic behavior of the rubber cord shell of the pneumatic spring of the high-speed railroad rolling stock, taking into account the design features of the railroad track, namely the rail joint. The methodology for experimental testing of the pneumatic spring of the high-speed railroad rolling stock using the proposed dynamic test installation is given. Experimental tests of the pneumatic spring were carried out within the rail joint of the railroad track, which has a vertical ledge of 7.0 mm. It was established that the maximum value of the accelerations of the rubber cord shell of the pneumatic spring occurs in the vertical plane. The maximum vertical accelerations of the rubber cord shell of the pneumatic spring were 2.4 m/s2, horizontal transverse accelerations – 0.85 m/s2, and horizontal longitudinal accelerations – 0.9 m/s2. It was determined that the deformations of the pneumatic spring in the vertical plane are higher than the deformations in the horizontal plane. The value of the maximum vertical deformations of the pneumatic spring was 4.1 mm, while the maximum value of horizontal deformations was 1.2 mm. The natural frequencies and logarithmic decrements of oscillations damping were determined based on the obtained records of the free oscillations of the rubber cord shell of the pneumatic spring. It was established that the value of the first natural frequency of oscillations of the pneumatic spring is 3.21 Hz. The logarithmic decrement of oscillation damping of the rubber cord shell of the pneumatic spring was determined based on the constructed graph of oscillation damping with an approximating exponent. It is 0.2147. The obtained values of the dynamic indicators of the new pneumatic spring could be used in the future to control changes in the physical and mechanical properties of the rubber cord shell of the pneumatic spring under the operational conditions of the railroad track. In practice, engineers and scientists will be able to take into account the obtained dynamic parameters of the spring when designing and improving the pneumatic spring for high-speed train movement.
Determining the Strained State of Prefabricated Metal Corrugated Structures of a Tunnel Overpass Exposed to the Dynamic Loading from Railroad Rolling Stock
(РС Тесhnology Сеntеr, Kharkiv, Ukraine, 2022) Kovalchuk, Vitalii V.; Koval, Maksym; Onyshchenko, Artur; Kravets, Ivan B.; Bal, Olena M.; Markul, Ruslan V.; Vikhot, S.; Petrenko, Oleksiy V.; Rybak, Roman; Milyanych, Andriy R.
ENG: This paper reports the analysis of prospects for the use of prefabricated metal corrugated structures in the body of the embankment of a railroad track in the form of a tunnel overpass in order to pass road vehicles and railroad rolling stock. A technique of inertial dynamic tests of the deformed state of a tunnel overpass from prefabricated metal corrugated structures during the passage of railroad rolling stock is given, by measuring accelerations at the top and on the sides of overpass structures. An algorithm is proposed for processing the acceleration signal for assessing the strained state of metal corrugated structures of a tunnel overpass under the action of dynamic load from railroad transport. Experimental dynamic measurements of accelerations arising at the top and on the sides of a tunnel overpass during the passage of passenger and freight railroad rolling stock were carried out. The maximum value of accelerations arising at the top of a tunnel overpass during the passage of a freight train was 7.99 m/s2, and when passing a passenger train – 6.21 m/s2; the maximum accelerations that occur on the sides were 2.63 m/s2 and 1.77 m/s2. It is established that the maximum deformations of metal corrugated structures of the top of a tunnel overpass, when passing freight and passenger trains are, respectively, 1.63 mm and 1.11 mm. The maximum strains of metal corrugated structures on the sides of an overpass are 1.07 mm and 0.48 mm. The value of relative deformations in the vertical and horizontal dimensions of the structures of a tunnel overpass under the action of dynamic loads from the railroad rolling stock has been found. The relative vertical strains of an overpass amounted to 0.020 %; horizontal – 0.012 %. The practical significance of this work is that with the help of the devised procedure for measuring accelerations, it is possible to assess the strained state of metal corrugated structures under the influence of dynamic loads from the railroad rolling stock.
Development of a Promising System for Diagnosing the Frogs of Railroad Switches Using the Transverse Profile Measurement Method
(PC "Technology Center", Ukrainian State University of Railway Transport, Kharkov, 2018) Kovalchuk, Vitalii V.; Sysyn, Mykola P.; Hnativ, Yuriy M.; Bal, Olena M.; Parneta, Bohdan Z.; Pentsak, Andrii Ya.
EN: We have developed a system for diagnosing the frogs of railroad switches, based on the application of modern microcontrollers of the type ESP with high technical characteristics and the simultaneous use of the information technology IoT (Internet of Things). The proposed system has advantages over mechanical systems in terms of the accuracy of data, their operational processing and submission to user in order to analyze technical condition of frogs at railroad switches. The results of measuring the transverse profile of frogs at railroad switches make it possible to take scientifically-substantiated decisions regarding the need for recovery repair of frogs by the method of surfacing and for control over gradual decrease in their carrying capacity, for establishing their actual technical condition and residual resource. We carried out experimental-theoretical research into longitudinal profile of frogs at railroad switches laid on the reinforced concrete bars. It was established as a result that after passing 50–65 million tons of cargo (that corresponds to the medium degree of wear) the trajectory takes the shape of a bump. We observe sharp hollows on the reinforced concrete base in the zone where a wheel rolls from a rail wing onto the core, characterized by significant total inclination. Subsequently, when the passed cargo increases, the number of sinusoidal irregularities grows. At wear close to maximal (80–95 million tons passed), the percentage of unfavorable trajectories (sinusoidal and hollows) grows; at low wear, they make up 49.8 %, at a wear of 5−6 mm and larger – 88.3 %. Sometimes there is a transformation of the sinusoidal irregularities into the wave-shaped ones. We have established characteristic motion trajectories of the center of mass of the wheel over the frog depending on the wear of rail wings and the core of a frog and the passed cargo. A mathematical model was constructed for predicting the wear of frog profile depending on the total weight of passed cargo.
Development of Devices for Long-Term Railway Track Condition Monitoring: Review of Sensor Varieties
(Óbuda University. Budapest, Hungary, 2025) Kurhan, Dmytro; Kovalchuk, Vitalii V.; Markul, Ruslan V.; Kovalskyi, Denis
ENG: There are numerous methods for monitoring the condition of railway tracks. In most cases, either the geometry of the railway track or its interaction parameters with moving trains are checked. This work is a component of a project aimed at developing a methodology for installing sensors (sensor networks) for continuous (long-term) monitoring of railway track condition. Therefore, its main objective is to analyse and discuss interim results regarding the feasibility of applying various types of sensors installed on railway track elements. The authors considered three options for sensor application for the overall assessment of railway track condition: measuring stresses in rails with strain gauges, measuring accelerations of rail and sleeper vibrations with accelerometers, and measuring the speed of wave propagation in ballast. Each method has its own advantages and disadvantages. Considering the analysis conducted, each method, both independently and in combination with others, can be applicable for building systems for long-term monitoring of railway track condition. Such systems can be useful, both for solving practical track maintenance tasks during operation and for scientific research.
Devising a Procedure for Assessing the Subgrade Compaction Degree Based on the Propagation Rate of Elastic Waves
(РС Тесhnology Сеntеr, Kharkiv, Ukraine, 2021) Kovalchuk, Vitalii V.; Kravets, Ivan B.; Nabochenko, Olga S.; Onyshchenko, Artur; Fedorenko, Olexander; Pentsak, Andriy; Petrenko, Oleksiy V.; Hembara, Nataliya
EN: This paper reports the analysis of the methods for estimating the technical condition of the subgrade underneath a constructed railroad track or road during its operation. The study results have proven that the issue related to monitoring and controlling high-quality compac-tion of a heterogeneous subgrade remains relevant and requires the construction of reliable experi-mental methods for assessing the subgrade degree of compaction.A procedure for determining the compaction of subgrade in the laboratory has been devised, based on inertial microcomputer technologies, which makes it pos-sible to assess the degree of com-paction of subgrade soils depend-ing on the propagation rate of an impact's elastic waves.An experimental study has been performed into the propaga-tion rate of elastic waves across a homogeneous subgrade made of coarse-grained sand and a hetero-geneous subgrade made of coarse sand with a layer of clay in the middle of the prism. The study results established that the propa-gation rate of an elastic wave in a heterogeneous subgrade accepts a lower value than the rate of wave propagation in a homogeneous subgrade.Through the dynamic inter-pretation, by using a discriminant statistical analysis, the character-istic features have been defined in the distribution of accelerations in the body of the homogeneous and heterogeneous subgrade, depend-ing on the degree of compaction, which would make it possible to monitor the state of the subgrade during operation. As the degree of the subgrade soil compaction affects the technical condition of roads.
Devising a Procedure to Calculate and Analyze Parameters for Passing the Flood and Breakthrough Wave Taking into Consideration the Topographical and Hydraulic Riverbed Irregularities
(РС Тесhnology Сеntеr, Kharkiv, Ukraine, 2022) Onyshchenko, Artur; Ostroverkh, Вorys; Potapenko, Liudmila; Kovalchuk, Vitalii V.; Tokin, Оleksndr; Harkusha, Mykola; Bashkevych, Іryna; Koretskyi, Andrii; Khvoshchynska, Nadiia; Rolinska, Iryna
ENG: It has been established that the most likely period of breakthrough wave occurrence is the time of spring flooding or heavy rain when water-head facilities are subjected to significant loads that lead to the collapse of their individual elements or the entire structure. In addition, the possibility of man-made accidents that can occur at any time cannot be ruled out. It has been proven that breakthrough wave formation depends on the nature of the destruction or the overflow through a water-head facility. For the study reported in this paper, a model of the kinematics of riverbed and breakthrough flows was used, which is based on the equations of flow, washout, and transport of sediments that are averaged for the depths of the stream. The differential equations describing the nonstationary flow averaged for depth are solved using the numerical grid system FST2DH (2D Depth-averaged Flow and Sediment Transport Model), which implements a finite-element method on the plan of a riverbed's topographic region. These tools are publicly available, which allows their wide application to specific loads and boundary conditions of mathematical models. The construction of an estimation grid involving the setting of boundary conditions and the use of geoinformation system tools makes it possible to simulate the destruction of a culvert of the pressure circuit and obtain results for a specific case of an actual riverbed and a water-head facility. It has been established that there is a decrease in the speed of wave propagation along the profile, from 3 m/s to 1 m/s. The impact of bottom irregularities, the effect of floodplains, and the variety of bottom roughness have also been assessed, compared to the results of their calculation based on one-dimensional models given in the regulatory documents. Hydraulic calculations were carried out taking into consideration the related properties of the main layer of the floodplain, which consists of peat accumulations, and the heterogeneity of the depths and roughness of floodplain surfaces of soils. It has been established that there is almost no erosion of supports in the floodplain zone in this case. It was found that as the distance between the flow and breakthrough intersection increases, there is a decrease in the height of the head from 2.1 m to 1.25 m.
Estimation of Carrying Capacity of Metallic Corrugated Structures of the Type Multiplate MP 150 During Interaction with Backfill Soil
(PC "Technology Center", Ukrainian State University of Railway Transport, Kharkov, 2018) Kovalchuk, Vitalii V.; Kovalchuk, Yuri; Sysyn, Mykola P.; Stankevych, Volodymyr Z.; Petrenko, Oleksiy V.
EN: We estimated the stressed state of a railroad structure with a large cross section spanning more than 6 m, which is made from metallic corrugated sheets of the type Multiplate MP 150. The stressed-strained state of the corrugated structure was estimated depending on the residual deformation of vertical diameter of the pipe, the modulus of elasticity of backfill soil, and the degree of compaction. The study conducted has demonstrated that maximum stresses occur on the horizontal sides of a metallic pipe, and maximum deformations ‒ in the pipe vault. It was established that an increase in the degree of compaction of backfill soil leads to a decrease in the stresses in a metallic pipe by almost half. The stresses grow much faster with an increase in irregularity on the railroad track. Numerical calculations have shown that the equivalent stresses exceed the permissible magnitude of 235 MPa when the degree of compaction of backfill soil is below 90 % and an operational irregularity on the track develops beyond the permissible magnitude. Operational observations have shown that the pipe is most vulnerable, in terms of resistance against the formation of a plastic hinge, in the initial period of operation when the backfill soil has not yet reached the standard compaction. At the initial stage of operation of a metallic corrugated pipe it is necessary to improve the level of technological control in order to timely detect railroad track's irregularities that exceed the standards, and to eliminate them. Under normal operational conditions, a metallic corrugated structure has a rather large reserve of carrying capacity, which amounts to 80 %. However, these structures, despite their high initial strength margin, are very sensitive to an increase in external dynamic loads due to the occurrence of irregularity on the railroad track.
Evaluation Deflected Mode of Point Frogs Mark 1/11 Finite Element Method
(НВП ПП «Технологічний Центр», Харків, 2017) Kovalchuk, Vitalii V.; Bolzhelarskyi, Yaroslav V.; Parneta, Bogdan Z.; Pentsak, Andriy; Petrenko, Oleksiy V.; Mudryy, Ihor B.
EN: We carried out evaluation of the stressed-strained state of crossings of turnouts by the finite element method in the Ansys programming complex. It was established that under conditions of three-axial compression, at large stresses of vertical compression, the cracks of multi-cycle metal fatigue of the crossing develop. It was found that the development of defects by the code DS 14.1-14.2 on the rolling surface of the cast part of a wing rail and the crossing’s core occurs due to high contact stresses near the edge of the working face of a wing rail and the crossing’s core. They occur in this region in the form of cyclically repeated and sign-alternating normal and tangential stresses from cyclically recurring power impacts from the wheels of rolling stock of railroad transport. It was established that for the normal stresses, values that are maximal by absolute magnitude correspond to the moment when a wheel passes the estiamted cross section of the crossing. For the tangential stresses, on the contrary, at the moment when the wheel is over the estimated cross section, their magnitude is close to zero. The obtained results of the stressed-strained state of crossings are necessary for the optimal design of transverse and longitudinal profiles of the crossing. This will make it possible to extend operation life cycle of the crossings of turnouts and save state budget resources for their current maintenance and repair.
Evaluation of RailWay Ballast Layer Consolidation After Maintenance Works
(Czech Technical University, Prague, 2019) Sysyn, Mykola P.; Nabochenko, Olga S.; Kovalchuk, Vitalii V.; Gerber, Ulf
EN: Abstract. The results of the study of the ballast layer consolidation after the work of ballast-tamping machines of different types are given in the article. The existing methods of determining the degree of consolidation of the ballast layer are analysed. The seismic method was improved by means of a complex dynamic and kinematic interpretation of the impulse response. For the dynamic interpretation with the use of statistical analysis, the features are selected so that they correspond to the degree of consolidation of the ballast layer. On the basis of researches, a device and software were developed that allow an automated evaluation of the ballast layer consolidation based on the kinematic and dynamic analysis of the measured impulse response. The measurements of the degree of the ballast layer consolidation after an operation of ballast-consolidation machines in different sequences allowed establishing the efficiency of the consolidation and the feasibility of the machines’ application.
Evaluation of the Stressed-Strained State of Crossings of the 1/11 Type Turnouts by the Finite Element Method
(ПП "Технологічний центр", Український державний університет залізничного транспорту, 2017) Kovalchuk, Vitalii V.; Bolzhelarskyi, Yaroslav V.; Parneta, Bohdan Z.; Pentsak, Andrii Ya.; Petrenko, Oleksii V.; Mudryy, Ihor B.
EN: We carried out evaluation of the stressed-strained state of cross-ings of turnouts by the finite element method in the Ansys program-ming complex. It was established that under conditions of three-axial compression, at large stresses of vertical compression, the cracks of multi-cycle metal fatigue of the crossing develop. It was found that the development of defects by the code DS 14.1-14.2 on the rolling surface of the cast part of a wing rail and the crossing’s core occurs due to high contact stresses near the edge of the working face of a wing rail and the crossing’s core. They occur in this region in the form of cyclically repeated and sign-alternating normal and tangential stresses from cyclically recurring power im-pacts from the wheels of rolling stock of railroad transport. It was established that for the normal stresses, values that are maximal by absolute magnitude correspond to the moment when a wheel passes the estiamted cross section of the crossing. For the tangential stresses, on the contrary, at the moment when the wheel is over the estimated cross section, their magnitude is close to zero. The obtained results of the stressed-strained state of crossings are necessary for the optimal design of transverse and longitudinal profiles of the crossing. This will make it possible to extend operation life cycle of the crossings of turnouts and save state budget resources for their current maintenance and repair.

Browsing by Author "Kovalchuk, Vitalii V."

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