Browsing by Author "Németh, Attila"

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Investigation of “Open” Superstructure Tramway Tracks in Budapest
(2023) Jóvér, Vivien; Major, Zoltán; Németh, Attila; Kurhan, Dmytro ; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.
Investigation of the Geometrical Deterioration of Paved Superstructure Tramway Tracks in Budapest (Hungary)
(MDPI, 2023) Jóvér, Vivien; Major, Zoltán; Németh, Attila; Kurhan, Dmytro; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.
Investigation of the Geometrical Deterioration Process of Tramway Superstructure Systems – A Case Study
(2026) Jóvér, Vivien; Major, Zoltán; Németh, Attila; Sysyn, Mykola P.; Kurhan, Dmytro; Fischer, Szabolcs
ENG: Tramway tracks deteriorate over time due to operational loads, environmental conditions, and structural factors. This study analyzes the geometric degradation of Budapest's tramway tracks using long-term measurements. Track gauge and longitudinal level were assessed with the TrackScan 4.01 instrument to evaluate deterioration across different superstructure types. Findings indicate that concrete slab tracks experience gauge widening, while embedded rail systems tend to narrow under similar conditions, with structural design playing a greater role than traffic intensity. Measurement limitations highlight the need for improved monitoring tools. These insights support more effective maintenance strategies, ensuring greater durability and sustainability.
Investigation of the Geometrical Deterioration Process of Tramway Superstructure Systems – A Case Study
(2026) Jóvér, Vivien; Major, Zoltán; Németh, Attila; Sysyn, Mykola P.; Kurhan, Dmytro; Fischer, Szabolcs
ENG: Tramway tracks deteriorate over time due to operational loads, environmental conditions, and structural factors. This study analyzes the geometric degradation of Budapest's tramway tracks using long-term measurements. Track gauge and longitudinal level were assessed with the TrackScan 4.01 instrument to evaluate deterioration across different superstructure types. Findings indicate that concrete slab tracks experience gauge widening, while embedded rail systems tend to narrow under similar conditions, with structural design playing a greater role than traffic intensity. Measurement limitations highlight the need for improved monitoring tools. These insights support more effective maintenance strategies, ensuring greater durability and sustainability.
Laboratory and Numerical Investigation of Pre-Tensioned Reinforced Concrete Railway Sleepers Combined with Plastic Fiber Reinforcement
(MDPI, 2024) Németh, Attila; Ibrahim, Sarah Khaleel; Movahedi, Rad M.; Szalai, Szabolcs; Major, Zoltán; Kocsis Szürke, Szabolcs; Jóvér, Vivien; Sysyn, Mykola; Kurhan, Dmytro; Harrach, Dániel; Baranyai, Gusztáv; Fekete, Imre; Nagy, Richárd; Csótár, Hanna; Madarász, Klaudia; Pollák, András; Molnár, Bálint; Hermán, Bence; Kuczmann, Miklós; Gáspár, László; Fischer, Szabolcs
ENG: : 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.
Laboratory and Numerical Investigation of Pre-Tensioned Reinforced Concrete Railway Sleepers Combined with Plastic Fiber Reinforcement
(MDPI, Basel, Switzerland, 2024) Németh, Attila; Ibrahim, Sarah Khaleel; Movahedi Rad, Majid; Szalai, Szabolcs; Major, Zoltán; Kocsis Szürke, Szabolcs; Jóvér, Vivien; Sysyn, Mykola; Kurhan, Dmytro; Harrach, Dániel; Baranyai, Gusztáv; Fekete, Imre; Nagy, Richárd; Csótár, Hanna; Madarász, Klaudia; Pollák, András; Molnár, Bálint; Hermán, Bence; Kuczmann, Miklós; Gáspár, László; Fischer, Szabolcs
ENG: 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.
Numerical Investigation of Pre-Stressed Reinforced Concrete Railway Sleeper for High-Speed Application
(MDPI, 2023) Major, Zoltán; Ibrahim, Sarah Khaleel; Rad, Majid Movahedi; Németh, Attila; Harrach, Dániel; Herczeg, Géza; Szalai, Szabolcs; Kocsis Szürke, Szabolcs; Harangozó, Dóra; Sysyn, Mykola; Kurhan, Dmytro ; Baranyai, Gusztáv; Gáspár, László; Fischer, Szabolcs
ENG: 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.
Optimization of 3D Printed Rapid Prototype Deep Drawing Tools for Automotive and Railway Sheet Material Testing
(MDPI, 2023) Szalai, Szabolcs; Herold, Bálint; Kurhan, Dmytro; Németh, Attila; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.
Optimization of Surface Cleaning and Painting Methods for DIC Measurements on Automotive and Railway Aluminum Materials
(MDPI, 2023) Szalai, Szabolcs; Fehér, Viktória; Kurhan, Dmytro ; Németh, Attila; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.
Optimization of Surface Preparation and Painting Processes for Railway and Automotive Steel Sheets
(MDPI, 2023) Szalai, Szabolcs; Szívós, Brigitta Fruzsina; Kurhan, Dmytro ; Németh, Attila; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.
Testing of Lubricants for DIC Tests to Measure the Forming Limit Diagrams of Aluminum Thin Sheet Materials
(MDPI, 2023) Szalai, Szabolcs; Csótár, Hanna; Kurhan, Dmytro ; Németh, Attila; Sysyn, Mykola; Fischer, Szabolcs
ENG: 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.