Mykola Sysyn
57200815763
Publications - 37
QUANTITATIVE ANALYSIS AND OPTIMIZATION OF ENERGY EFFICIENCY IN ELECTRIC MULTIPLE UNITS
Publication Name: Facta Universitatis Series Mechanical Engineering
Publication Date: 2025-08-01
Volume: 23
Issue: 2
Page Range: 351-375
Description:
The increasing urgency for sustainable transportation solutions necessitates a thorough examination of energy efficiency within railway systems. This study investigates the energy performance of Siemens Ventus (i.e., Siemens Desiro ML type) electric multiple units on Austria's Raaberbahn network, focusing on route-specific energy consumption and the optimization of regenerative braking. Utilizing data collected from January to May 2023, the research employs a robust methodology that integrates statistical analysis, curve-fitting, and geospatial modeling to assess energy trends along routes connecting Vienna, Bratislava, and Deutschkreutz. The findings reveal that terrain, operational practices, and external environmental factors significantly contribute to energy inefficiencies. Specifically, hotspots of energy overconsumption were identified, leading to the development of tailored optimization models for each route. The analysis also produced heatmaps that illustrate critical spatial and temporal patterns, which are essential for implementing targeted interventions aimed at enhancing energy efficiency.
Open Access: Yes
Driver Distraction Detection in Extreme Conditions Using Kolmogorov–Arnold Networks
Publication Name: Computers
Publication Date: 2025-05-01
Volume: 14
Issue: 5
Page Range: Unknown
Description:
Driver distraction can have severe safety consequences, particularly in public transportation. This paper presents a novel approach for detecting bus driver actions, such as mobile phone usage and interactions with passengers, using Kolmogorov–Arnold networks (KANs). The adversarial FGSM attack method was applied to assess the robustness of KANs in extreme driving conditions, like adverse weather, high-traffic situations, and bad visibility conditions. In this research, a custom dataset was used in collaboration with a partner company in the field of public transportation. This allows the efficiency of Kolmogorov–Arnold network solutions to be verified using real data. The results suggest that KANs can enhance driver distraction detection under challenging conditions, with improved resilience against adversarial attacks, particularly in low-complexity networks.
Open Access: Yes
Deformation Characterization of Glass Fiber and Carbon Fiber-Reinforced 3D Printing Filaments Using Digital Image Correlation
Publication Name: Polymers
Publication Date: 2025-04-01
Volume: 17
Issue: 7
Page Range: Unknown
Description:
The paper offers an in-depth deformation study of glass fiber-reinforced and carbon composite filaments of 3D printers. During the certification, the authors used DIC (Digital Image Correlation) as a full-field strain measurement technique to explore key material traits as a non-contact optical measurement method. The insights captured through the DIC technology enabled to better understand the localized strain distributions during the loading of these reinforced filaments. The paper analyzes the glass fiber and carbon fiber filaments used in 3D printing that are reinforced with these materials and are subjected to bending and compressive loading. The segment presents how loading affects the performance of reinforced filaments when varying such factors as the deposition patterns, layer orientation, and other process parameters. Different types and combinations of reinforcements and printing variables were tested, and the resulting dependencies of mechanical parameters and failure modes were established for each case. Key conclusions demonstrate that the mechanical behavior of both carbon- and glass fiber-reinforced filaments is strongly affected by the 3D printing parameters, particularly infill density, pattern, and build orientation. The application of Digital Image Correlation (DIC) allowed for a precise, full-field analysis of strain distribution and deformation behavior, offering new insights into the structural performance of fiber-reinforced 3D printed composites. The findings from the study provide guidance for the proper choice of filling material and the optimal parameters for the 3D printing process of models with high-performance indexes and seamless applications in the automotive and industrial manufacturing sectors.
Open Access: Yes
Evaluating 3D-Printed Polylactic Acid (PLA)-Reinforced Materials: Mechanical Performance and Chemical Stability in Concrete Mediums
Publication Name: Applied Sciences Switzerland
Publication Date: 2025-02-01
Volume: 15
Issue: 4
Page Range: Unknown
Description:
The optimization and evaluation of 3D-printed polylactic acid (PLA) materials for reinforcing concrete elements present a promising avenue for advancing sustainable construction methods. This study addresses the challenges associated with PLA’s dual nature—biodegradable yet mechanically limited for long-term applications—while leveraging its potential to enhance concrete reinforcement. The research identifies gaps in understanding PLA’s mechanical and chemical behavior in alkaline environments, particularly its interactions with concrete matrices. To bridge this gap, four distinct PLA variants (high-impact PLA, engineering PLA, electrical ESD PLA, and gypsum PLA) and ABS (acrylonitrile butadiene styrene) were subjected to dissolution tests in NaOH solutions (pH 12 and 12.55) and mechanical evaluation under three-point bending using digital image correlation (DIC) technology. Test specimens were prepared using optimized 3D printing strategies to ensure structural consistency and were embedded in concrete beams to analyze their reinforcement potential. Force–displacement data and GOM ARAMIS measurements revealed significant differences in mechanical responses, with peak loads ranging from 0.812 kN (high-impact PLA) to 1.021 kN (electrical ESD PLA). Notably, electrical ESD PLA exhibited post-failure load-bearing capacity, highlighting its reinforcement capability. Chemical dissolution tests revealed material-specific degradation patterns, with high-impact and Gypsum PLA showing accelerated surface changes and precipitation phenomena. Observations indicated white crystalline precipitates, likely lime (calcium hydroxide—Ca(OH)2 ), residue from the dissolution tests (sodium hydroxide—NaOH), or material-derived residues formed on and near PLA elements, suggesting potential chemical interactions. These findings underline the critical role of material selection and optimization in achieving effective PLA–concrete integration. While PLA’s environmental sustainability aligns with industry goals, its structural reliability under long-term exposure remains a challenge. The study concludes that electrical ESD PLA demonstrates the highest potential for application in reinforced concrete, provided its chemical stability is managed, as its peak value (1.021 kN) showed 25.7% higher load-bearing capacity than high-impact PLA (0.812 kN) and did not lose any of its structural stability in the dissolution tests. This work advances the understanding of PLA as a sustainable alternative in construction, offering insights for future material innovations and applications.
Open Access: Yes
DOI: 10.3390/app15042165
Void Geometry Identification with Track-Side Rail Deflection Measurements
Publication Name: Lecture Notes in Networks and Systems
Publication Date: 2025-01-01
Volume: 1258 LNNS
Issue: Unknown
Page Range: 188-202
Description:
One of the most common failure types that rapidly deteriorates track geometry is sleeper voids or unsupported sleepers. Ballast pulverization, or so-called “white spots”, is a sign that indicates the presence of the high sleeper voids in the track. However, the objective estimation of the size and form of voids is possible by time- and cost-consuming track-side measurements at many points along the track. The study presents an efficient model-based approach for the identification of the void geometry by the track-side experimental measurements of rail deflection in one point. A robust 3-beam track model with a two-mass vehicle model together with a time-effective surrogate optimization algorithm is used for the multidimensional search of the void geometry that is fitting to experimental data. The results show that the void geometry could be found precisely with one-point measurements, significantly reducing the time and cost involved in the process. Therefore, a practical, simplified method of determining the void zone's depth and length is proposed. It is based on analyzing the relation between void sizes and the rail deflection wave sizes. Unlike the void depth, the void length cannot be found by the simple difference between the deflection waves in the void and the reference zones. The proposed method assumes wave estimation by applying deflection thresholds, ensuring a practical and reliable approach. The reliability of the proposed method in estimating void length and depth instills confidence in the effectiveness of the approach. Finally, it was used to estimate the void length and depth for many problem zones in ballast tracks that were inspected with track-side measurements. The result analysis shows that the void length and depth are subjected to a non-linear relation: the long-length voids have unproportionally higher depths than short voids. The results indicate that the settlement intensity of the neighbor-to-void sleepers is much lower than that of the hanging sleepers.
Open Access: Yes
Investigation of Digital Light Processing-Based 3D Printing for Optimized Tooling in Automotive and Electronics Sheet Metal Forming
Publication Name: Journal of Manufacturing and Materials Processing
Publication Date: 2025-01-01
Volume: 9
Issue: 1
Page Range: Unknown
Description:
This study addresses the emerging need for efficient and cost-effective solutions in low-volume production by exploring the mechanical performance and industrial feasibility of cutting tools that are fabricated using stereolithography apparatus (SLA) technology. SLA’s high-resolution capabilities make it suitable for creating precise cutting dies, which were tested on aluminum sheets (Al99.5, 0.3 mm, and AlMg3, 1.0 mm) under a 60-ton hydraulic press. Measurements using digital image correlation (DIC) revealed minimal wear and deformation, with tolerances consistently within IT 0.1 mm. The results demonstrated that SLA-printed tools perform comparably to conventional metal tools in cutting and bending operations, achieving similar surface quality and edge precision while significantly reducing the production time and cost. Despite some limitations in wear resistance, the findings highlight SLA technology’s potential for rapid prototyping and short-run manufacturing in the automotive and electronics sectors. This research fills a critical gap in understanding SLA-based tooling applications, offering insights into process optimization to enhance tool durability and broaden material compatibility. These advancements position SLA technology as a transformative tool-making technology for flexible manufacturing.
Open Access: Yes
DOI: 10.3390/jmmp9010025
Investigation of FDM-Based 3D Printing for Optimized Tooling in Automotive and Electronics Sheet Metal Cutting
Publication Name: Applied Sciences Switzerland
Publication Date: 2025-01-01
Volume: 15
Issue: 1
Page Range: Unknown
Description:
Within the scope of the work, the possible use of fused deposition modeling (FDM) technology in executing rapid prototypes of cutting tools for aluminum sheets was systematically studied. Relevant investigations have thus far mainly concentrated on tools for the 3D printing of bent and deep-drawn pieces, yet the implementation of FDM tools in cutting has been insufficiently covered. This study aims to determine the characteristics of FDM cutting tools, such as wear and tear, dimensional stability, and cutting efficiency. Various tool designs were tested under different wall thicknesses and orientations with respect to the feed of Al99.5 sheets with thicknesses of 0.22 mm and 0.3 mm. According to the results, in the best case, three-dimensional printed PLA tools performed six cuts with no burrs and an acceptable wear level due to the IT tolerances (IT9 and IT10). Tools with thicker walls and more appropriate orientations were found to be more robust. However, some designs failed when subjected to greater loads, revealing a deficiency in some of the strength properties of the material. These observations suggest that it is possible to create 3D printed tools for modeling and small-scale production at considerably cheaper and faster rates than conventional methods. Future work will integrate advanced materials and designs to enhance tool performance, further solidifying FDM as a transformative approach in industrial tool manufacturing. With this research, the authors wanted to demonstrate that FDM technology can also be used to produce a classic sheet cut, which, of course, is still of great importance for prototyping or setting up production processes. This research demonstrated that FDM printing can play a role in this area.
Open Access: Yes
DOI: 10.3390/app15010442
Field Application of Austenitic Filler Metals for Repairing Rail Surface Defects in Paved Tracks
Publication Name: Lecture Notes in Networks and Systems
Publication Date: 2025-01-01
Volume: 1258 LNNS
Issue: Unknown
Page Range: 87-95
Description:
Previous research by the authors identified a welding technology to repair rail defects in tramways with partial disassembly and partial preheating, with the following main advantages for the operator: the process can be carried out during operational downtime or even during traffic, disassembly, and repair costs are reduced, and traffic disruption is reduced compared to conventional hard surfacing welding technologies. After welding, the hardening under traffic should approach the vehicle wheels’ hardness values (310–350 HB). In the track measurements under investigation, welds were made on two different rail grades using austenitic weld metal with high elongation relative to the rails, which was also compared with welds made by conventional hard surfacing welding. The present study aims to determine the hardening function of austenitic dowel bars at different layer counts by performing continuous hardness measurements at the investigated sites. The hardening shows a power function at the initial stage and a linear trend after about 2.5 million MGT.
Open Access: Yes
INVESTIGATION OF HEAT-AFFECTED ZONES OF THERMITE RAIL WELDINGS
Publication Name: Facta Universitatis Series Mechanical Engineering
Publication Date: 2024-12-01
Volume: 22
Issue: 4
Page Range: 689-710
Description:
The paper investigates the heat-affected zone (HAZ) of several rail joints executed by thermite rail welding (TW). The examined rail profile was 54E1 (UIC54). The rail steel categories were different: R260 and R400HT. The welding portions of the TWs fitted R350HT and R260 rail categories with normal welding gaps. The rail pieces were brand new, i.e., without any usage in the railway track. The authors executed Vickers-hardness tests (HV10) and material texture tests on the running surface of the rail head, as well as on slices cut from the rail head. The cutting was performed by the water jet method, five longitudinal direction slices with vertical cutting lines. The considered specimen lengths were 2×70 mm (i.e., 70 mm from the mid-point of the rail joint), however, the depths were 20 mm from the running surface. Therefore, the measuring spaces were 5 mm lengthwise and 2 mm in depth. The variation of the hardness values was determined considering the microstructures of the base steel material and the TW. For comparison, previously measured Elektrothermit SoW-5 and earlier own research were taken into consideration.
Open Access: Yes
Mechanism of cross-level settlements and void accumulation of wide and conventional sleepers in railway ballast
Publication Name: Railway Engineering Science
Publication Date: 2024-09-01
Volume: 32
Issue: 3
Page Range: 361-383
Description:
The cross-level and twist irregularities are the most dangerous irregularity types that could cause wheel unloading with the risk of derailments and additional maintenance expenses. However, the mechanism of the irregularities initiation and development is unclear. The motivation of the present study was the previous experimental studies on the application of wide sleepers in the ballasted track. The long-term track geometry measurements with wide sleepers show an enormous reduction of the vertical longitudinal irregularities compared to the conventional track. However, wide sleepers had higher twist and cross-section level irregularities. The present paper aims to explain the phenomenon by discrete element method (DEM) modeling the development process of sleeper inhomogeneous support at cross-level depending on the sleeper form. The DEM simulations show that the maximal settlement intensity is up to 3.5 times lower for a wide sleeper in comparison with the conventional one. Nevertheless, the cross-level differential settlements are almost the same for both sleepers. The particle loading distribution after all loading cycles is concentrated on the smaller area, up to the half sleeper length, with fully unloaded zones under sleeper ends. Ballast flow limitation under the central part of the sleeper could improve the resilience of wide sleepers to the development of cross-level irregularities. The mechanism of initiation of the cross-level irregularity is proposed, which assumes the loss of sleeper support under sleeper ends. The further growth of inhomogeneous settlements along the sleeper is assumed as a result of the interaction of two processes: ballast flow due to dynamic impact during void closing and on the other side high pressure due to the concentration of the pressure under the middle part of the sleeper. The DEM simulation results support the assumption of the mechanism and agree with the experimental studies.
Open Access: Yes
Ballast Settlement Accumulation in Zones with Unsupported Sleepers
Publication Name: Transportation Infrastructure Geotechnology
Publication Date: 2024-08-01
Volume: 11
Issue: 4
Page Range: 2598-2637
Description:
The high influence of impact and vibration on the behavior of crushed stone and ballast materials has been known for a long time. The zones with unsupported sleepers, which are always present in transition zones, crossings, welds, etc., are typically characterized by impact interaction, ballast full unloading, and additional preloading. However, no studies on ballast layer settlements consider impact vibration loading. Moreover, the influence of the cyclic loading on the ballast settlement intensity is considered ambiguously, with both decelerating and accelerating trends. The comprehensive literature review presents the influence of factors on settlement intensity. The present study aims to estimate the long-term processes of sleeper settlement accumulation depending on the loading factors: impact, cyclic loading, and preloading. The typical for a void zone ballast loading pattern was determined for various void sizes and the position along the track by using a model of vehicle-track interaction that was validated by experimental measurements. The loading patterns were parametrized with four parameters: maxima of the cyclic loading, impact loading, sleeper acceleration, and minimal preloading. A specially prepared DEM simulation model was used to estimate the ballast settlement intensity after initial settlement stabilization for more than 100 loading patterns of the void zone cases. The settlement simulation results clearly show that even a low-impact loading pattern causes many times increased settlement intensity than ordinary cyclic loading. Moreover, the initial preloading in the neighbor-to-void zones can cause even a decrease in the settlement intensity compared to the full ordinary or partial unloading. A statistical analysis using a machine learning approach and an analytic one was used to create the model for the intensity prediction regarding the loading patterns. The analytic approach demonstrates somewhat lower prediction quality, but it allows to receive plausible and simple analytic equations of the settlement intensity. The results show that the maximal cyclic loading has a nonlinear influence on the settlement intensity that corresponds to the 3–4 power function, and the impact loading is expressed by the linear to parabolic function. The ballast’s minimal preloading contributes to the reduction of the settlement intensity, especially for high cyclic loadings that are typical for neighbor-to-void zones. The results of the present study could be used for the complementing of the present phenomenological equations with the new factors and further application in the algorithms of the settlements accumulation prediction.
Open Access: Yes
Laboratory and Numerical Investigation of Pre-Tensioned Reinforced Concrete Railway Sleepers Combined with Plastic Fiber Reinforcement
Szabolcs Fischer
Mykola Sysyn
Zoltán Major
Sarah Khaleel Ibrahim
Dmytro Kurhan
Vivien Jóvér
Szabolcs Szalai
Hanna Csótár
Klaudia Madarász
András Pollák
Dániel Harrach
Bálint Molnár
L. Gaspar
Bence Hermán
Szabolcs Kocsis Szurke
Attila Németh
I. Fekete
Richárd Nagy
Gusztáv Baranyai
Miklós Kuczmann
M. Movahedi Rad
Publication Name: Polymers
Publication Date: 2024-06-01
Volume: 16
Issue: 11
Page Range: Unknown
Description:
This research investigates the application of plastic fiber reinforcement in pre-tensioned reinforced concrete railway sleepers, conducting an in-depth examination in both experimental and computational aspects. Utilizing 3-point bending tests and the GOM ARAMIS system for Digital Image Correlation, this study meticulously evaluates the structural responses and crack development in conventional and plastic fiber-reinforced sleepers under varying bending moments. Complementing these tests, the investigation employs ABAQUS’ advanced finite element modeling to enhance the analysis, ensuring precise calibration and validation of the numerical models. This dual approach comprehensively explains the mechanical behavior differences and stresses within the examined structures. The incorporation of plastic fibers not only demonstrates a significant improvement in mechanical strength and crack resistance but paves the way for advancements in railway sleeper technology. By shedding light on the enhanced durability and performance of reinforced concrete structures, this study makes a significant contribution to civil engineering materials science, highlighting the potential for innovative material applications in the construction industry.
Open Access: Yes
The Application of DIC in Criminology Analysis Procedures to Measure Skin Deformation
Publication Name: Journal of Applied and Computational Mechanics
Publication Date: 2024-01-01
Volume: 10
Issue: 4
Page Range: 817-829
Description:
In engineering, DIC is a widely used measurement technique. Its major advantage is that it provides real-time results (displacements, accelerations, stresses, strains, deformations) of the surface under examination relatively quickly and without contact. However, its application in medicine, biomechanics, and the field of criminalistics is novel. The present research focuses mainly on the frontier areas of forensics and medicine. The research aims to define the test boundary conditions and preparatory activities to measure the surface of the animal and then human skin. Injuries caused by low-energy ballistic bullets, blunt-force trauma, and cuts and punctures caused by knives and/or blades will be investigated. The present research focuses on puncture injuries in animal skin. The main challenge is to create a speckle pattern on the surface that can track deformation well. The research is about developing and validating this. The GOM ARAMIS measurement system was applied for the measurements. This paper demonstrates that a suitable preparation, painting procedure, and measurement setup has been established to measure the above effects, i.e., to identify displacements and deformations of up to tenths of a millimeter with sufficient accuracy. The evaluation of the results will also show that this method could be used in forensic applications, the automotive industry, medical orthopedics, and the textile industry.
Open Access: Yes
TESTING THE FRAGMENTATION OF RAILWAY BALLAST MATERIAL BY LABORATORY METHODS USING PROCTOR COMPACTOR
Publication Name: Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu
Publication Date: 2024-01-01
Volume: Unknown
Issue: 1
Page Range: 58-68
Description:
The physical classification of crushed stone and gravel used in railway construction is based on their strength and endurance and is performed by a laboratory test method using a rotating drum or a mortar method. The values of fracture resistance calculated using the Los Angeles method and abrasion calculated using the Micro-Deval method show a corresponding correlation and require further investigation. Purpose. The development of a new method for measuring rock material fracture that is consistent with widely used standards while also being more comparable to real-world railway operating conditions. Certainly, both standard tests are essential for ensuring product homogeneity during production, so the new recommended method is only a supplement. Methodology. The Proctor device was used to induce so-called shock loads from above, similar to railway loading conditions. Unlike the standard method, the andesite material was placed in a standard cylinder in these tests. The samples were pre-screened and sorted; the specified weight was approximately 1,300 g, and the specified sizes of the individual particles were 6.3, 8.0 and 11.2 mm. Only prewashed and dried materials of NZ (fine crushed stone) or KZ (special crushed stone) from four different quarries (Tállya, Szob, Nógrádkövesd, Recsk) with different rock physics characteristics were considered. The Proctor compactor machine was used because of its calculable labor (19.86 J/impact) and the crushing effect of the calculable impacts (64, 128, 256 and 1,028 blows). Even after loading different numbers of impacts, homogeneous samples from different quarries were sieved to measure the masses of fragments per fraction. Findings. The set of measurements made it possible to establish a series of fragmentation and degradation curves for each of the three repeated measurements based on the composition of the material and the number of blows, which showed the degradation of samples with different physical and mechanical properties of the rock material and particle sizes. With an increasing number of impacts, the amount of crushed material in the sample increased, but the distribution of crushed material did not decrease evenly and proportionally as the number of impacts increased. Parameters and indices were also computed to identify various correlations (i. e., FV , d < 22.4, d < 0.5, d < 0.063 mm, CU , M ratio, λ ratio). Some of them (e. g., FV ) needed to be changed, but they were predefined due to the nature of the tests. Originality. While many standard and alternative railway track ballast fragmentation test methods and measurement tools are available, this paper proposes a new laboratory method and demonstrates the specific measurement and application effectiveness. Practical value. In addition to standard tests that are already widely used, the new method for measuring the fractional composition of railway ballast can help simulate real-world operating conditions of a railroad track in the laboratory. This method will improve the safety of railway operations.
Open Access: Yes
ADVANTAGES OF USING CONCRETE CANVAS MATERIALS IN RAILWAY TRACK CONSTRUCTION
Publication Name: Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu
Publication Date: 2024-01-01
Volume: Unknown
Issue: 1
Page Range: 50-57
Description:
Purpose. Justification of the feasibility of using new types of drainage materials, such as Concrete Canvas (CC), under the upper structure of the railway permanent way. Methodology. The tasks were solved by a complex research method, including analysis and generalization of literary and patent sources, analytical, experimental studies, using computer and mathematical modeling methods. Tests were conducted with and without the CC layer in a multi-level shear box. After the shear test, the specimens were also tested for load-bearing capacity (E2 , according to the Hungarian standard) and particle breakage. The contact surface between the bottom of the ballast and the CC was measured using a precision 3D laser scanner (GOM ATOS) and visualized graphically using AutoCAD software. Findings. Experimental testing of the vertical load during connection and analysis compared with the test results of geocomposite/geogrid structures, internal shear resistance, and other parameters proved the structure’s higher load-bearing capacity with the CC layer. Based on the results, the Concrete Canvas structure provides higher reinforcement than the average geogrid type. Originality. The advantages of using new Concrete Canvas materials in the structure of a railway track have been demonstrated for the first time to provide greater internal shear resistance than the average for geogrids. Practical value. These results may provide primary data for using Concrete Canvas in railway tracks and superstructures in the future.
Open Access: Yes
Studying the Relation of the Residual Stresses in the Ballast Layer to the Elastic Wave Propagation
Publication Name: Transportation Infrastructure Geotechnology
Publication Date: 2023-12-01
Volume: 10
Issue: 6
Page Range: 962-987
Description:
During track construction or ballast bed maintenance, ballast layer compaction quality plays an essential role in the following track irregularity accumulation, its lifecycle, and maintenance costs. The ballast compaction process is characterized by its compaction and the accumulation of the stressed state. The elastic wave propagation methods are an effective way for the identification of the ballast bed compaction properties. The paper presents the theoretical and experimental studies of the ballast consolidation under the vibration loading of the sleeper. The practical laboratory study is given by the 1:2.5 scaled physical model of one sleeper and the corresponding ballast layer box. The measurements of ballast pressure and deformations under the vibration loading in the ballast layer and the photogrammetric recording of the ballast flow are carried out. The measurements demonstrate the accumulation of the residual stresses under the ballast layer. Furthermore, the measurements of elastic wave time of flight (ToF) using the shakers under the sleeper and acceleration sensors under the ballast show the substantial increase of the ToF velocities after the tamping process. Moreover, the distribution of the velocities along the sleeper is spatially inhomogeneous. The numeric simulation using the discrete element method (DEM) of the tamping and the testing processes proves the inhomogeneous wave propagation effect. The modeling shows that the main reason for the wave propagation inhomogeneity is the accumulated residual stress distribution and the minor one – the compaction density. Additionally, a method for identifying wave velocity spatial distribution is developed by wave tracing the inhomogeneous medium. The procedures allow ballast identification in the zones outside the shakers.
Open Access: Yes
Investigation of the Bearing Capacity of Transport Constructions Made of Corrugated Metal Structures Reinforced with Transversal Stiffening Ribs
Publication Name: Infrastructures
Publication Date: 2023-09-01
Volume: 8
Issue: 9
Page Range: Unknown
Description:
Methods of increasing the bearing capacity of corrugated metal structures of transport constructions using transversal stiffening ribs in the form of additional corrugation and stiffeners are given. Based on the theory of elasticity, a mathematical model for estimating the stress-strain state of transport constructions made of corrugated metal structures reinforced with stiffening ribs in the form of double corrugation was developed. The method of determining equivalent forces during rolling stock passage is offered. It has been established that double corrugation increases the bearing capacity of corrugated metal structures. Therefore, additional corrugation of corrugated metal structures reduces stresses by up to 20% and deflections by 50%. The obtained results show that the increase in rolling stock speed does not lead to a significant increase in stresses and strains in CMS when the railway track corresponds to the design state.
Open Access: Yes
Investigation of the Geometrical Deterioration of Paved Superstructure Tramway Tracks in Budapest (Hungary)
Publication Name: Infrastructures
Publication Date: 2023-08-01
Volume: 8
Issue: 8
Page Range: Unknown
Description:
In the 21st century, one of the key requirements is to develop and maintain our infrastructure facilities most efficiently using the available resources. Tramways are of significant national economic importance and represent an important national asset. There are currently seven different types of superstructure systems in Hungary, based on the national regulations and the related requirements currently in force. This paper compares the paved tramway superstructure systems in the context of track geometry, through-rolled axle tons of track, and the age of track sections. Paved tracks have many benefits, but the main ones are easier maintenance and road traffic use. Elastically supported continuous rail bedding (ESCRB; in Hungary, this is known as “RAFS”) and “large” slab superstructure systems are used to create paved superstructure systems. Road crossings use the latter systems, while heavily loaded lines use several ESCRB systems. This article examines the geometrical changes in several ESCRB superstructure systems. A TrackScan 4.01 instrument was used to take measurements in June and September 2021 and in April 2022, September 2022, and May 2023. Track gauge, alignment, and longitudinal level are examined. Regardless of the ESCRB superstructure system or age, a medium-loaded line’s track gauge trendline increases, which means that the track gauge is widening and, regardless of traffic load or age, the average longitudinal level is constantly increasing from year to year. When it is a medium-loaded line, the average value of alignment increases slightly, and the trendline is almost straight, but it decreases when it is an extremely heavily loaded line. The authors will analyze how the reference track section will change in the future. Based on the results, it is important to assess how subsequent measurements affect the trend lines. Because the data evaluations show similar results, comparing open tramway tracks to paved ones is crucial.
Open Access: Yes
A Risk Assessment Technique for Energy-Efficient Drones to Support Pilots and Ensure Safe Flying
Publication Name: Infrastructures
Publication Date: 2023-04-01
Volume: 8
Issue: 4
Page Range: Unknown
Description:
Unmanned Aerial Vehicles, also known as UAVs, play an increasingly important part in daily life. However, the ever-increasing number of UAVs pose an ever-increasing threat to the transportation infrastructure. Despite their precision and general efficiency, infrastructural-scale Unmanned Aerial Systems (UASs) have a disadvantage regarding their capability of being implanted in the ecosystem. There are several reasons for this, but the primary bottleneck is that their systems are not transparent to society and have very complicated processes. As a result, the authors decided to investigate the functional properties of UASs and make improvements to those properties. Throughout the study, the authors’ primary focus was on analysis, which boosts productivity and ensures a significant level of safety for routine flights. The amount of power that a UAV uses depends on several variables, including the amount of power that its individual components require, the temperature of its surroundings, and the condition of the battery that it is powered by. Therefore, critical parameters and interdependencies are taken into account in the risk assessment strategy for energy-efficient Unmanned Aerial Vehicles (UAVs). In the case of UAVs, the algorithm performs a risk calculation before take-off to estimate the amount of risk that can be associated with the given flight time when using the provided battery. On the one hand, several instances of the pre-take-off state and how its parameters interact are investigated. On the other hand, they demonstrate the calculation of the risk while in flight, which is based on actual flight data.
Open Access: Yes
Prediction system of rolling contact fatigue on crossing nose based on support vector regression
Publication Name: Measurement Journal of the International Measurement Confederation
Publication Date: 2023-03-31
Volume: 210
Issue: Unknown
Page Range: Unknown
Description:
It is essential to assess the rolling contact fatigue (RCF) of turnouts and maintain them in advance. It saves a lot of money while protecting the safety of railway operations. In Germany, the damage on rails, especially crossing noses, mainly depends on the subjective judgment of experts. There are no objective and comprehensive evaluation criteria. This paper presents the application of image processing and supervised machine learning algorithms to crossing nose fatigue judgment. The fatigue characteristics of the crossing nose rolling contact surface along the life cycle of the crossing nose are analyzed. The study used crack information from magnetic particle inspection (MPI) images of crossing nose surfaces. It uses basic image processing methods to collect physical information about features of fatigue cracks in images. Existing feature selection methods are used to exclude irrelevant features and retain valuable features. And we select the best feature selection method through the regression results. Statistically significant crack features and combinations that depict the surface fatigue state are found. In this paper, by comparing several usually machine learning regression algorithms, it is found that the supervised learning of support vector machine regression (SVR) has achieved the best results in the regression fitting of the crack feature data in this paper. The regression results form a simple system to evaluate the life cycle of crossing nose. The system finds the location of cracks that can create dangerous defects in the crossing nose surface. The research result consists of the early prediction of rail contact fatigue.
Open Access: Yes
Optimization of 3D Printed Rapid Prototype Deep Drawing Tools for Automotive and Railway Sheet Material Testing
Publication Name: Infrastructures
Publication Date: 2023-03-01
Volume: 8
Issue: 3
Page Range: Unknown
Description:
The main objective of this research is to identify optimal printing strategies and PLA (polylactic acid) filament materials to produce rapid prototype deep drawing tools. Additive 3D printing technologies have been applied for a long time to produce tools, but the research is unique in that it uses conventional and various reinforced PLA materials with conventional FDM (Fused Deposition Modeling) printers. The advantage of this method is that PLA is easy to print and recycle and does not require expensive or special printers, this also gives the article its novelty. A further aim was to produce the tools using commercially available low-end printers. DX53D 0.8 mm thick body steel and AlMg3 2.5 mm thick sheet were the materials to be molded for the tests. The test tool was an Erichsen deep drawing punch. Tool wear was tested using the GOM ATOS measuring system, an optical coordinate measuring machine based on the DIC (Digital Image Correlation) principle, which is also popular in the automotive industry. The study aims to determine the 3D printing and material parameters that can safely produce a minimum batch of 100 parts.
Open Access: Yes
Testing Road Vehicle User Interfaces Concerning the Driver’s Cognitive Load
Publication Name: Infrastructures
Publication Date: 2023-03-01
Volume: 8
Issue: 3
Page Range: Unknown
Description:
This paper investigates the usability of touch screens used in mass production road vehicles. Our goal is to provide a detailed comparison of conventional physical buttons and capacitive touch screens taking the human factor into account. The pilot test focuses on a specific Non-driving Related Task (NDRT): the control of the on-board climate system using a touch screen panel versus rotating knobs and push buttons. Psychological parameters, functionality, usability and, the ergonomics of In-Vehicle Information Systems (IVIS) were evaluated using a specific questionnaire, a system usability scale (SUS), workload assessment (NASA-TLX), and a physiological sensor system. The measurements are based on a wearable eye-tracker that provides fixation points of the driver’s gaze in order to detect distraction. The closed road used for the naturalistic driving study was provided by the ZalaZONE Test Track, Zalaegerszeg, Hungary. Objective and subjective results of the pilot study indicate that the control of touch screen panels causes higher visual, manual, and cognitive distraction than the use of physical buttons. The statistical analysis demonstrated that conventional techniques need to be complemented in order to better represent human behavior differences.
Open Access: Yes
Numerical Investigation of Pre-Stressed Reinforced Concrete Railway Sleeper for High-Speed Application
Publication Name: Infrastructures
Publication Date: 2023-03-01
Volume: 8
Issue: 3
Page Range: Unknown
Description:
The current paper deals with the numerical investigation of a unique designed pre-stressed reinforced concrete railway sleeper for the design speed of 300 km/h, as well as an axle load of 180 kN. The authors applied different methodologies in their research: traditional hand-made calculations and two types of finite element software. The latter were AxisVM and ABAQUS, respectively. During the calculations, the prestressing loss was not considered. The results from the three methods were compared with each other. The hand-made calculations and the finite element modeling executed by AxisVM software are adequate for determining the mechanical inner forces of the sleeper; however, ABAQUS is appropriate for consideration of enhanced and sophisticated material models, as well as the stress-state of the elements, i.e., concrete, pre-stressed tendons, etc. The authors certified the applicability of these methodologies for performing the dimensioning and design of reinforced concrete railway sleepers with pre-stressing technology. The research team would like to continue their research in an improved manner, taking into consideration real laboratory tests and validating the results from FE modeling, special material models that allow calculation of crackings and their effects in the concrete, and so that the real pattern of the crackings can be measured by GOM Digital Image Correlation (DIC) technology, etc.
Open Access: Yes
Optimization of Surface Preparation and Painting Processes for Railway and Automotive Steel Sheets
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
The article deals with DIC (Digital Image Correlation) tests on steel plates used in the automotive and railway industries, as well as in the construction industry. The most critical part of DIC tests is the quality of proper surface preparation, painting, and random patterns. The paint mediates the deformation of the optical systems, and its quality is paramount. The authors’ goal in this research is to determine the optimal dye–cleaning–drying time parameters for DIC studies. Commercially available surface preparation and cleaning agents were tested alongside commercially available spray paints. Standard and specific qualification procedures were applied for the measurements. Once the appropriate parameters were determined, the results were validated and qualified by GOM ARAMIS tests. Based on the results, DIC measurements can be performed with higher accuracy and safety in laboratorial and industrial conditions, compared to the traditional deformation measurements executed by dial gauges or linear variable differential transformers.
Open Access: Yes
Investigation of “Open” Superstructure Tramway Tracks in Budapest
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
The most important thing nowadays is to use available resources to develop infrastructure as efficiently as possible. In this regard, evaluating the deterioration of tramway tracks is critical from both a technical and an economic viewpoint. In Hungary, seven types of superstructure systems are currently differentiated in the case of tramway transport, but the geometrical deterioration, lifecycle, and lifecycle cost of the tramway tracks are not accurately known. The current study aimed to evaluate and compare the results of track geometry measurements of two different “open” tramway superstructure systems depending on their traffic load and age. The geometry measurements we re executed by TrackScan 4.01 instrument, developed and maintained by a Hungarian developer company called Metalelektro Méréstechnika Ltd. The evaluation of the measurements showed a clear relationship between the traffic load, age, and track deterioration. Based on the results, it can be generally stated, concerning “open” superstructure systems, that regardless of the “open” superstructure system or the level of traffic load, the average value of alignment is decreasing; however, the average value of the longitudinal level is increasing. Furthermore, the deterioration of an older ballasted track with lower traffic is similar to that of a younger ballasted track that has a higher traffic load. Another significant result was that the deterioration of the track gauge parameter in the case of concrete slab tracks is clearly described as the broadening of the track gauge.
Open Access: Yes
Optimization of Surface Cleaning and Painting Methods for DIC Measurements on Automotive and Railway Aluminum Materials
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
The preparatory operations of DIC (Digital Image Correlation) tests were investigated in this study, with special emphasis on specimen cleaning and painting operations. As it is well known, DIC tests are non-contact and applied in materials research, the analysis of complex structures, and, nowadays, the construction industry. The use of DIC technologies has seen a dynamic increase in all scientific fields. In our study, aluminum body panels for automotive and railway applications were tested using this technique. There are many articles on proper patterning in the literature but fewer on preparation and priming. These are critical for a successful DIC measurement. This paper looks at different surface cleaners and primers with different grading procedures and will also determine the time window within which the paint should be applied. Finally, the GOM ARAMIS system was applied to measure and characterize the painted surface and visible deformation defects resulting from inadequate painting.
Open Access: Yes
Testing of Lubricants for DIC Tests to Measure the Forming Limit Diagrams of Aluminum Thin Sheet Materials
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
We investigated lubricants and thin teflon foils that can be applied in the formability testing of the thin aluminum sheets used in the electronics and automotive industries. For the tests, thirteen different industrial lubricants (oils and greases) (i.e., L1–L13) and two Teflon films (i.e., 0.08 and 0.22 mm thick) were applied. The authors conducted an Erichsen test, and the thickness reduction of the discs was measured first. In forming-limit curve (FLC) tests, it is crucial that the stresses are localized in the central area of the specimen during forming and that biaxial deformation is maintained throughout, if possible. We aimed to achieve and fulfill this task. To perform this measurement, the GOM ARAMIS measuring system was utilized. It is an optical measuring system based on the digital image correlation (DIC) principle, capable of measuring both stresses and displacements in real time. A specific validation method was also developed to qualify the DIC system. We concluded that there was a 5% difference in Erichsen indentation (IE) number diagrams between the best (L12) and worst (L4) cases for the lubricants and oils tested, which is a significant difference for thin plates. We found that this value could be increased and improved by using Teflon discs. Furthermore, the localization of stress maxima, i.e., the centering of cracks in the specimen, could be achieved by combining Teflon discs and L12 lubricant (with appropriate layer order), which significantly aids in the recording of standard FLC diagrams. Using foils is also advantageous because they are readily available, have no expiry date, and are of less environmental concern.
Open Access: Yes
Vibration Diagnostic Methods of Automatic Transmission Service Requirement Prediction
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
Automatic transmission is a key factor for autonomous driving. The transmission condition is highly affected by the quality and quantity of transmission oil in the system. However, the oil condition is not monitored in the system, and the oil change interval and method are still a subject of discussion. This paper analyzes the effects of oil changes in automatic transmissions. The measurements were carried out before and after the oil change with the same external conditions. With the vibration measurement method, data can be collected without disassembling the parts and during operational conditions. Furthermore, time- and frequency-based analyses were conducted to compare different transmissions’ operations. The results have shown that the effect of oil degradation is measurable on the amplitude of the signals and, therefore, predictable with vibration diagnostics. During the evaluation, the maximum values were compared on measurements with at least a 2-s length.
Open Access: Yes
Examination of Concrete Canvas under Quasi-Realistic Loading by Computed Tomography
Publication Name: Infrastructures
Publication Date: 2023-02-01
Volume: 8
Issue: 2
Page Range: Unknown
Description:
The current paper concerns the investigation of CC (Concrete Canvas), a unique building material from the GCCM (geosynthetic cementitious composite mat) product group. The material is suitable for trench lining, trench paving, or even military construction activities, while the authors’ purpose is to investigate the application of the material to road and railway substructure improvement. This research was carried out to verify the material’s suitability for transport infrastructure and its beneficial effects. The authors’ previous study reported that the primary measurements were puncture, compression, and the parameters evaluated in four-point bending (laboratory) tests. However, based on the results, finite element modeling was not feasible because the testing of the composite material in a single layer did not provide an accurate indication. For this reason, the material characteristics required for modeling were investigated. A unique, novel testing procedure and assembly were performed, wherein the material was loaded under quasi-realistic conditions with a crushed stone ballast sample and other continuous particle size distribution samples in a closed polyethylene tube. In addition, the deformation of the material following deformed bonding was measured by computed tomography scanning, and the results were evaluated.
Open Access: Yes
Analysis of the Stressed State of Sand-Soil Using Ultrasound
Publication Name: Infrastructures
Publication Date: 2023-01-01
Volume: 8
Issue: 1
Page Range: Unknown
Description:
The maintenance of the ballast substructure is an important cost-driver for railway systems. The problem is that today’s condition monitoring methods are insufficient to collect detailed data on the compaction and stress allocation inside the ballast bed. That makes it challenging to improve the maintenance technology and organization. This study aimed to investigate the applicability of the ultrasound method for analyzing the state of stress of sand-soil and the relation between the residual stress and wave propagation velocity. The experiments on the sand in a box with different allocations of the ultrasonic receivers and pressure measurement cells were produced under different external loading. In addition, the vertical and horizontal stress distributions were measured. The results showed a correlation between the test load, the state of stress, and the ultrasound propagation velocity. Moreover, the residual stresses after the loading cycles were analyzed.
Open Access: Yes
Numerical Optimization of Battery Heat Management of Electric Vehicles
Publication Name: Journal of Applied and Computational Mechanics
Publication Date: 2023-01-01
Volume: 9
Issue: 4
Page Range: 1076-1092
Description:
Lithium-ion battery technology in the modern automotive industry utilizes highly temperature-sensitive batteries. Here, air cooling strategies will be the most applicable for the chosen example based on strategies for temperature control. Simulations have been utilized to evaluate the different thermal management strategies. A battery model was developed using the solutions offered by Computational Fluid Dynamics (CFD) simulation technology. It utilizes the heat produced by the discharge of the battery cells. Due to the simulation's limited computational capacity, the energy transfer model was implemented with a simplified but sufficiently complex physical mesh. Ten actual measurements were conducted in the laboratory to investigate the heating of the cell during the charging and discharging of 18650-type batteries. The results were applied to validate the simulation model. The simulation outcomes and thermal camera readings were compared. The cell-level numerical model was then extended to examine the temperature variation at the system level. The primary design objective is to achieve the highest energy density possible, which necessitates that the cells be constructed as closely as possible; however, increasing the distance between the cells can provide superior cooling from a thermal management perspective. The effect of varying the distance between individual cells on the system's heating was analyzed. Greater distance resulted in a more efficient heat transfer. It was also discovered that, in some instances, a small distance between cells produces inferior results compared to when constructed adjacently. A critical distance range has been established based on these simulations, which facilitates the placement of the cells.
Open Access: Yes
GEOMETRY VARIATION OF BALLASTED RAILWAY TRACKS DUE TO WEATHER CONDITIONS
Publication Name: Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu
Publication Date: 2023-01-01
Volume: Unknown
Issue: 1
Page Range: 74-79
Description:
Purpose. Investigate and establish the relationship between track geometry measurements and weather conditions to determine the parameters that influence the lifetime of railway tracks' superstructure system. The study of ballasted beds of railway tracks is very important for operation and maintenance in case of main lines, industrial sidings and mine transport. Methodology. Determination of the annual load of the selected section based on the regulations. Compari of the track parameters measurements made by TrackScan 4.01 instrument in different seasons and temperatures. Among the parameters measured by the instrument, the track gauge, alignment, longitudinal level, and superelevation parameters are considered and analyzed in this article.Since the main lines' traffic are permanently loaded with passenger and freight transport and the industrial sidings and mine tracks are used in the production process, the examinations can only be done on tramway tracks during the standstills at night. The results of these measurement on tramway tracks can help to understand the identify of railway tracks' lifetime and can be used in mainlines, industrial and mining railway tracks. Findings. The change in the average values of selected track geometrical parameters is analyzed, considering the typical weather conditions. Based on the measurement and results, there is an evident connection between the evaluated results of track geometry measurements and the change in weather conditions. Originality. Finding the relationship between changes in track geometry values and weather conditions on the basis of an evaluation of track geometry measurements taken on average every third month. Practical value. The results can then be used as input data for determining the service life of the track superstructure in the case of tramways, mainlines, industrial and mining railway tracks.
Open Access: Yes
INNER SHEAR RESISTANCE INCREASING EFFECT OF CONCRETE CANVAS IN BALLASTED RAILWAY TRACKS
Publication Name: Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu
Publication Date: 2023-01-01
Volume: Unknown
Issue: 2
Page Range: 64-70
Description:
Purpose. To prove that the GCCM (geosynthetic cementitious composite mat) – type Concrete Canvas (CC) – is an adequate supplementary layer on the top of the subgrade. As its drainage function is known, this article tries to prove the reinforcement possibility. This layer is relatively thin; nevertheless, it can behave like the geogrids. It is the main path to finding out the opportunity of the interlocking effect and its impact on the railway ballast’s inner shear resistance. Methodology. The laboratory measurements were performed in a multilevel shear box, which allows simulating the multilevel shift of the ballast layer. The tests were planned with and without the CC layer. After shearing, the samples were also tested for loadbearing capacity (E2 ; according to the Hungarian Standard) and particle breakage. On the other hand, the contact surface between the lowest part of the ballast and CC was also measured by a sophisticated 3D laser scanner (GOM ATOS) and graphically by AutoCAD software. Findings. After the results of the laboratory experiments are analyzed, the following parameters are calculated and determined: 1) the reinforcement ratio as the tangent of the inner shear resistance curves in the 5–15 mm horizontal shearing interval as well as the area under graphs by integration in the 0–40 mm interval; 2) the change in loadbearing capacity of the layerstructure with and without CC; 3) the amount of the cement particles; 4) the amount of the broken particles; 5) contact surface between the lowest layer of ballast and CC; 6) flatness of CC sheets after shearing. Based on the results, the Concrete Canvas provides significant reinforcement to the railway ballast. Originality. Any other type of measurement with Concrete Canvas in a multilevel shear box is unknown. The topic is unique. Practical value. In the future, these results may provide baseline data to verify the suitability of the Concrete Canvas in the railway sub or superstructure for various types of transport.
Open Access: Yes
Evolution of Rail Contact Fatigue on Crossing Nose Rail Based on Long Short-Term Memory
Publication Name: Sustainability Switzerland
Publication Date: 2022-12-01
Volume: 14
Issue: 24
Page Range: Unknown
Description:
The share of rail transport in world transport continues to rise. As the number of trains increases, so does the load on the railway. The rails are in direct contact with the loaded wheels. Therefore, it is more easily damaged. In recent years, domestic and foreign scholars have conducted in-depth research on railway damage detection. As the weakest part of the track system, switches are more prone to damage. Assessing and predicting rail surface damage can improve the safety of rail operations and allow for proper planning and maintenance to reduce capital expenditure and increase operational efficiency. Under the premise that functional safety is paramount, predicting the service life of rails, especially turnouts, can significantly reduce costs and ensure the safety of railway transportation. This paper understands the evolution of contact fatigue on crossing noses through long-term observation and sampling of crossing noses in turnouts. The authors get images from new to damaged. After image preprocessing, MPI (Magnetic Particle Imaging) is divided into blocks containing local crack information. The obtained local texture information is used for regression prediction using machine-supervised learning and LSTM network (Long Short-Term Memory) methods. Finally, a technique capable of thoroughly evaluating the wear process of crossing noses is proposed.
Open Access: Yes
DOI: 10.3390/su142416565
Optical Rail Surface Crack Detection Method Based on Semantic Segmentation Replacement for Magnetic Particle Inspection
Publication Name: Sensors
Publication Date: 2022-11-01
Volume: 22
Issue: 21
Page Range: Unknown
Description:
Railway damage detection is of great significance in ensuring railway safety. The cracks on the rail surface play a key role in studying the formation and development process of rail damage, predicting the occurrence of rail defects, and then improving the service life of the rail. However, due to the small shape of the cracks, the typical detection method is relatively complicated, and the speed is quite slow. Although traditional magnetic particle inspection technology is fairly accurate at detection, it is costly and inconvenient to carry and install, while also limiting the detection speed and affecting the system’s operation. In this paper, a semantic segmentation detection method is developed by using various collected rail surface crack data and deep learning through a neural network. By comparing the inspection of the same rail surface with magnetic particle inspection technology, only inexpensive cameras are used and the inspection speed is increased while maintaining relatively high accuracy. In addition, the method can achieve fast detection speeds if it is extended to be combined with high-frequency cameras. It is an economical, efficient, and environmentally friendly method for future rail surface detection.
Open Access: Yes
DOI: 10.3390/s22218214
Comparison of the effects and efficiency of vertical and side tamping methods for ballasted railway tracks
Publication Name: Construction and Building Materials
Publication Date: 2022-01-03
Volume: 314
Issue: Unknown
Page Range: Unknown
Description:
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.
Open Access: Yes
Investigation of interlocking effect of crushed stone ballast during dynamic loading
Publication Name: Reports in Mechanical Engineering
Publication Date: 2021-01-01
Volume: 2
Issue: 1
Page Range: 65-76
Description:
The present paper deals with the experimental investigation of interlocking effect of crushed stone ballast material, assessing it as the relationship with the residual and dynamic stresses under the ballast layer during laboratory dynamic tests with the consideration of different boundary conditions. The laboratory experiments were executed with a scaled model of ballast under the sleeper. The measured pressure at the bottom surface of the ballast has two parts: dynamic and residual. The dynamic part depends on the external loading; the residual part remains after unloading. The measured residual stress was observed up to 3 times higher than the stress due to cyclic external loading. The relationship of the residual stress and interlocking effect to ballast particles angularity is analyzed. A simple interpretation of the distribution of residual stress is proposed, that depends on the measured cyclic stress and the elasticity of bounding walls. The study of interlocking effect of ballast could be potentially useful for many practical problems of railway track design as well as for the track maintenance issues.
Open Access: Yes
