Browsing by Author "Szalai, Szabolcs"
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Item Examination of Concrete Canvas under Quasi-Realistic Loading by Computed Tomography(MDPI, 2023) Balázs, Eller; Movahedi, Rad M.; Fekete, Imre; Szalai, Szabolcs; Harrach, Dániel; Baranyai, Gusztáv; Kurhan, Dmytro ; Sysyn, Mykola; Fischer, SzabolcsENG: 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.Item Investigation of Digital Light Processing-Based 3D Printing for Optimized Tooling in Automotive and Electronics Sheet Metal Forming(MDPI, Basel, Switzerland, 2025) Szalai, Szabolcs; Szívós, Brigitta Fruzsina; Nemes, Vivien; Szabó, György; Kurhan, Dmytro; Sysyn, Mykola; Fischer, SzabolcsENG: 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.Item Investigation of FDM-Based 3D Printing for Optimized Tooling in Automotive and Electronics Sheet Metal Cutting(MDPI, Basel, Switzerland, 2025) Szalai, Szabolcs; Szívós, Brigitta Fruzsina; Nemes, Vivien; Szabó, György; Kurhan, Dmytro; Sysyn, Mykola; Fischer, SzabolcsENG: 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.Item 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, SzabolcsENG: 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.Item 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, SzabolcsENG: : 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.Item 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; Szürke, Szabolcs Kocsis; Harangozó, Dóra; Sysyn, Mykola; Kurhan, Dmytro ; Baranyai, Gusztáv; Gáspár, László; Fischer, SzabolcsENG: 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.Item 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, SzabolcsENG: 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.Item 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, SzabolcsENG: 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.Item 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, SzabolcsENG: 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.Item 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, SzabolcsENG: 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.Item Testing Road Vehicle User Interfaces Concerning the Driver’s Cognitive Load(MDPI, 2023) Nagy, Viktor; Kovacs, Gabor; Földesi, Péter; Kurhan, Dmytro; Sysyn, Mykola; Szalai, Szabolcs; Fischer, SzabolcsENG: 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.