Vivien Jóvér
57437364700
Publications - 10
Quantifying the Effect of Frame Stiffness – The Substitution Inertia of Meier's Calculation
Publication Name: Lecture Notes in Networks and Systems
Publication Date: 2025-01-01
Volume: 1258 LNNS
Issue: Unknown
Page Range: 46-57
Description:
The internationally accepted method for assessing track stability is the calculation based on Meier's theory. A critical point is the inclusion of the equivalent track bending stiffness. Practical measurements have often given contradictory results in determining this, so the authors present a purely theoretical determination in this article. For this purpose, the Nemesdy theory, which is used in Hungarian practice, is invoked. By applying this theory, the paper introduces an auxiliary factor that allows us to calculate the value of the inertia of the two rails on the vertical axis. Stopping at this point in the theoretical derivation and recognizing the possibility, an iterative solution is proposed by which the magnitude of the substitute inertia can be considered in Meier's calculation without performing the necessary calculations using Nemesdy's theory.
Open Access: Yes
Vehicle Dynamics Measurements with a Unique Measuring System for Trams
Publication Name: Lecture Notes in Networks and Systems
Publication Date: 2025-01-01
Volume: 1258 LNNS
Issue: Unknown
Page Range: 24-33
Description:
One of the paramount challenges in contemporary urban transport is the efficient maintenance and operation of tramway tracks, aiming to maximize their lifespan while ensuring safe and comfortable passenger travel. Traditional methods of examining superstructure systems through observation and geometric measurements are insufficient; understanding the dynamics of vehicles adhering to their schedules is equally critical. To address this, we developed an innovative portable vehicle dynamics measurement system equipped with accelerometers and a GPS module (with GNSS system), facilitating real-time tram dynamics testing. This versatile device can be deployed at any time and on any tram, enabling continuous monitoring of track conditions. The dynamic data gathered can be systematically compared with geometric measurements, providing comprehensive insights into the railway track's condition and informing maintenance strategies. The paper consists of several examples for comparison (geometric and dynamic data series) and discusses how to develop the instrument further.
Open Access: Yes
Dynamic Modeling Possibilities of Embedded Rail Structures
Publication Name: Acta Polytechnica Hungarica
Publication Date: 2025-01-01
Volume: 22
Issue: 4
Page Range: 29-43
Description:
In Hungarian design practice, the Zimmermann-Eisenmann quasi-static design method is employed to dimension track structures with embedded rails. This method determines the mean values of deformations and stresses using an infinitely long elastically embedded beam as the static frame. After establishing these mean values, the effects of track condition and speed are considered through Eisenmann multiplication, enabling the definition of design values. Conversely, international practices include methods that calculate deformations and stresses based on dynamic models incorporating viscoelastic embedding, directly accounting for speed but not dynamic effects due to track characteristics. This paper presents a solution to the dynamic problem, extending it to studying rotating frames beyond the commonly considered uniaxial solution. Each factor's effect is separately analyzed for track structures with embedded rail tracks, leading to a recommendation for the value of the "load multiplication factor".
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
Investigation of the Vertical Stability of Embedded Rail Structures
Publication Name: Advances in Transdisciplinary Engineering
Publication Date: 2024-01-01
Volume: 59
Issue: Unknown
Page Range: 37-43
Description:
In the case of embedded rail structures, the rails are fixed with a flexible embedding material that runs through a specially designed steel or reinforced concrete channel. The majority of the rail cross-section is embedded in these channels, eliminating the possibility of horizontal buckling as a failure mode. This paper investigates vertical stability, aiming to determine the stability resistance of a rail loaded with an initial failure in the vertical plane while considering elastic resistance. Vertical plane buckling is assumed to be a non-hazard for conventional rails because the wide rail footing can significantly inhibit vertical displacement, even without adhesion between the rail surface and the embedding material. However, the adhesion of the embedding material to the channel is adequate. Some rail sections lack adhesion between the rail and the embedding material due to the narrow width of the rail foot, making the phenomenon of "form-locking" uncertain, or the rail is partially embedded. In this article, the authors present a theoretical calculation method to investigate this problem, to transfer the results to everyday practice as simply as possible, and to present a solution suitable for manual calculation. Measuring the vertical spring constant in the method's input parameters under laboratory conditions is a difficult task, but by utilizing the possibilities provided by finite element modeling, the design can be significantly simplified. The introduced method has the significant advantage of quantifying the effect of vertical plane misalignments in the track compared to simpler solutions in the literature.
Open Access: Yes
DOI: 10.3233/ATDE240524
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
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
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
STATISTICAL ANALYSIS OF TRACK GEOMETRY PARAMETERS ON TRAMWAY LINE NO. 1 IN BUDAPEST
Publication Name: Baltic Journal of Road and Bridge Engineering
Publication Date: 2022-01-01
Volume: 17
Issue: 2
Page Range: 75-106
Description:
The article examines the superstructures of the tramway tracks of tramway line No. 1 in Budapest (the capital of Hungary). Since the first appearance of tramways, several technological advancements have been made to serve passenger needs as efficiently as possible. Several types of tramway track superstructure systems can be differentiated, which are implemented differently in each project. Furthermore, these superstructure types have different degradation times (both geometrical and structural), which depend on several factors. Nowadays, visual inspections are no longer considered sufficient in monitoring the tracks’ condition and deterioration, thus it is necessary to consider examinations carried out using the sensors mounted on the vehicles. Adopting appropriate methods, the measured data can be modeled and the life cycle of superstructures and structural elements can be determined as a result of sufficiently long-term studies (i.e., life cycle costs, the whole lifetime, etc.). First, the authors present a review of the relevant international literature, after that they conduct analysis of track geometry parameters of the superstructures related to five sections on the investigated tramway line based on the results of the measurements performed for three consecutive years between 2019 and 2021. The analyses consist primarily in statistical examination of the measured and calculated parameters.
Open Access: Yes
Investigation of Tramway Line No. 1, in Budapest, Based on Dynamic Measurements
Publication Name: Acta Polytechnica Hungarica
Publication Date: 2022-01-01
Volume: 19
Issue: 3
Page Range: 65-76
Description:
Determining the deterioration of superstructure systems is technical and has national economic importance. In addition to geometric deterioration, it is also very difficult to monitor the changes in the dynamic characteristics of the vehicles. The data from geometric and dynamic measurements should be properly analyzed to determine the deterioration, lifetime/life-cycle costs of superstructure systems and the casual relationships should be researched between the characteristics. In this paper, the geometric and dynamic measurement results of the two examined sections are compared. This analysis is the first step in exploring and understanding the relationship between each feature. The authors recommended methodologies for using the synchronized (static and dynamic) measurements and their evaluation possibilities related to tramway tracks. The method is a well-known solution for public railways; however, the tramways greatly differ. In Hungary, there is a great opportunity to introduce the static-dynamic parallel method, which can be applied for the determination of the life-cycle costs (LCC) of the tramway tracks that are assembled with different (super)structures.
Open Access: Yes
DOI: DOI not available
