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Keywords = ballast resistance

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15 pages, 4276 KiB  
Article
Effects of Stacking Configuration on Impact Resistance of Electric Locomotive Coupling Protective Covers Reinforced by CFRP, GFRP, and Their Hybrids
by Yanhui Xu, Jiyong Chen, Mingzhu Guan, Shoune Xiao, Guangwu Yang and Dongdong Chen
Materials 2025, 18(13), 3133; https://doi.org/10.3390/ma18133133 - 2 Jul 2025
Viewed by 305
Abstract
In the context of global environmental pollution and energy shortages, the use of lightweight designs of railway vehicles has become a key technological approach to improve energy efficiency and reduce carbon emissions. The use of lightweight and high-strength materials such as carbon-fiber-reinforced composites [...] Read more.
In the context of global environmental pollution and energy shortages, the use of lightweight designs of railway vehicles has become a key technological approach to improve energy efficiency and reduce carbon emissions. The use of lightweight and high-strength materials such as carbon-fiber-reinforced composites to replace traditional metal vehicle structures holds great application potential. In this study, random track loads and ballast impact loads that may occur during service were considered, and a finite-element model of the electric locomotive coupling protective cover was established. The impact resistance of CFRP, GFRP, and their interlayer hybrid configurations (C/G/C and G/C/G) against structural and ballast impacts were investigated. The calculation results showed that the CFRP protective cover exhibited the best structural impact resistance (with the lowest Tsai–Wu strength failure values), but it also had the largest maximum deformation displacement (2.36 mm) under ballast impact conditions. In contrast, the GFRP protective cover had a higher Tsai–Wu strength failure value, indicating that it had worse structural impact resistance, but it had a lower maximum deformation displacement (2.20 mm) under ballast impact conditions, demonstrating superior ballast impact resistance. The impact resistances of the hybrid-layered protective covers fell between those of the CFRP and GFRP in terms of the structural impact, while their ballast-impact resistance surpassed those of single-fiber configurations. Full article
(This article belongs to the Special Issue Engineering Materials and Structural Integrity)
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16 pages, 6596 KiB  
Article
Microstructure of Mortar with Ballast Waste as a Cement Replacement
by Santiago Yagüe-García and Rosario García-Giménez
Appl. Sci. 2025, 15(10), 5605; https://doi.org/10.3390/app15105605 - 16 May 2025
Viewed by 349
Abstract
The use of ballast in tracks generates waste that, in most cases, is destined for landfill. The proposal to use this waste as a replacement in OPC in different proportions valorizes the waste and allows its participation in the Circular Economy. To this [...] Read more.
The use of ballast in tracks generates waste that, in most cases, is destined for landfill. The proposal to use this waste as a replacement in OPC in different proportions valorizes the waste and allows its participation in the Circular Economy. To this end, two samples of ballast waste with substitution ratios (10, 15, and 20%) were studied for one year using pozzolanic activity, XRD, SEM/EDX, and CT scanning analysis. The shortest setting times corresponded to the ballast waste substitutions with the highest percentage, which is related to particle size and the presence of amorphous material, thereby reducing the setting time. The workability of mortars with a substitution indicates that the average consistency decreases as the substitution percentage increases, while the loss of fluidity grows with a higher substitution percentage. Porosity is linked to the formation of C-S-H gels and the presence of ettringite, which fills the pores between particles. Tortuosity can be considered low, which hinders the transport of aqueous solutions, making the substituted cements studied more resistant to hydration processes. Full article
(This article belongs to the Section Materials Science and Engineering)
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11 pages, 1872 KiB  
Article
Simulated Discharge of Ballast Water Reveals Potential Contribution to Spread of Antibiotic Resistance Genes in Geographically Isolated Receiving Waters
by Jianhong Shi, Chengyuan Ji, Rui Wang, Chaoli Sun and Baoyi Lv
Antibiotics 2025, 14(4), 340; https://doi.org/10.3390/antibiotics14040340 - 26 Mar 2025
Viewed by 648
Abstract
Background/Objectives: The propagation of antibiotic resistance genes (ARGs) poses a huge threat to environmental and human health. The ballast water from ships has been recognized as an important vector of ARGs. However, little is known about how ballast water from geographically isolated water [...] Read more.
Background/Objectives: The propagation of antibiotic resistance genes (ARGs) poses a huge threat to environmental and human health. The ballast water from ships has been recognized as an important vector of ARGs. However, little is known about how ballast water from geographically isolated water affects ARGs in receiving waters. Methods: Herein, we investigated the changes in ARGs in receiving water by microcosm experiments simulating the discharge of ballast water. Results: The simulated discharge of ballast water increased the abundances of target ARGs, which were 1.3–5.6-fold higher in the mixture of ballast water and receiving water (microcosm M) than in receiving water at the end of the experiment. The enrichment of target ARGs was significantly associated with MGEs. Moreover, the discharge of ballast water changed the microbial communities in receiving water. Further network analysis identified potential ARG hosts, such as Pseudohongiellaa and Amphritea, with the abundance in microcosm M (0.23% and 0.036%) being higher than in receiving water (0.09% and 0.006%), the changes of which might be responsible for ARG variations. Conclusions: Overall, our findings suggest the discharge of ballast water might promote the spread of ARGs in different geographical waters and the corresponding ecological risks should not be ignored. Full article
(This article belongs to the Special Issue Antibiotic Resistance in Wastewater Treatment Plants)
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20 pages, 21510 KiB  
Article
Visual Localization Method for Fastener-Nut Disassembly and Assembly Robot Based on Improved Canny and HOG-SED
by Xiangang Cao, Mengzhen Zuo, Guoyin Chen, Xudong Wu, Peng Wang and Yizhe Liu
Appl. Sci. 2025, 15(3), 1645; https://doi.org/10.3390/app15031645 - 6 Feb 2025
Cited by 2 | Viewed by 1001
Abstract
Visual positioning accuracy is crucial for ensuring the successful execution of nut disassembly and assembly tasks by a fastener-nut disassembly and assembly robot. However, disturbances such as on-site lighting changes, abnormal surface conditions of nuts, and complex backgrounds formed by ballast in complex [...] Read more.
Visual positioning accuracy is crucial for ensuring the successful execution of nut disassembly and assembly tasks by a fastener-nut disassembly and assembly robot. However, disturbances such as on-site lighting changes, abnormal surface conditions of nuts, and complex backgrounds formed by ballast in complex railway environments can lead to poor visual positioning accuracy of the fastener nuts, thereby affecting the success rate of the robot’s continuous disassembly and assembly operations. Additionally, the existing method of detecting fasteners first and then positioning nuts has poor applicability in the field. A direct positioning algorithm for spiral rail spikes that combines an improved Canny algorithm with shape feature similarity determination is proposed in response to these issues. Firstly, CLAHE enhances the image, reducing the impact of varying lighting conditions in outdoor work environments on image details. Then, to address the difficulties in extracting the edges of rail spikes caused by abnormal conditions such as water stains, rust, and oil stains on the nuts themselves, the Canny algorithm is improved through three stages, filtering optimization, gradient boosting, and adaptive thresholding, to reduce the impact of edge loss on subsequent rail spike positioning results. Finally, considering the issue of false fitting due to background interference, such as ballast in gradient Hough transformations, the differences in texture and shape features between the rail spike and interference areas are analyzed. The HOG is used to describe the shape features of the area to be screened, and the similarity between the screened area and the standard rail spike template features is compared based on the standard Euclidean distance to determine the rail spike area. Spiral rail spikes are discriminated based on shape features, and the center coordinates of the rail spike are obtained. Experiments were conducted using images collected from the field, and the results showed that the proposed algorithm, when faced with complex environments with multiple interferences, has a correct detection rate higher than 98% and a positioning error mean of 0.9 mm. It exhibits excellent interference resistance and meets the visual positioning accuracy requirements for robot nut disassembly and assembly operations in actual working environments. Full article
(This article belongs to the Section Applied Industrial Technologies)
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26 pages, 21318 KiB  
Article
Analysis of the Influence of Incorporating Different Thermal-Insulating Materials into the Sub-Ballast Layers
by Libor Ižvolt, Peter Dobeš, Martin Mečár and Deividas Navikas
Buildings 2025, 15(2), 239; https://doi.org/10.3390/buildings15020239 - 15 Jan 2025
Cited by 1 | Viewed by 684
Abstract
Adverse climatic conditions, particularly excessive water and frost, necessitate the design of thick protective sub-ballast layers when dealing with frost-susceptible subgrade surfaces, especially when using standard natural materials (crushed aggregate or gravel–sand). Given the current preference for conserving natural construction materials and promoting [...] Read more.
Adverse climatic conditions, particularly excessive water and frost, necessitate the design of thick protective sub-ballast layers when dealing with frost-susceptible subgrade surfaces, especially when using standard natural materials (crushed aggregate or gravel–sand). Given the current preference for conserving natural construction materials and promoting sustainable development in the dimensioning of sub-ballast layers, it is advisable to incorporate various thermal insulation, composite, or suitable recycled materials in their design. Therefore, the paper analyses the impact of incorporating different thermal insulation materials (including extruded polystyrene, Liapor, Liapor concrete, and composite foam concrete) into sub-ballast layers. As part of the experimental research, these modified sub-ballast layers were constructed on a real scale in the outdoor environment of the University of Žilina (UNIZA) campus. They were subsequently compared in terms of their thermal resistance to climatic loads. The research results demonstrate that extruded polystyrene provides the optimal thermal insulation effect in modified sub-ballast layers, which was subsequently used in the numerical modelling of railway track structure freezing under different climatic loads. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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15 pages, 7126 KiB  
Article
Study of Heat Distribution in Railway Switch Using Resistive Heater in Cold Climate Conditions
by Arefeh Lotfi, Adeel Yousuf and Muhammad Shakeel Virk
Appl. Sci. 2024, 14(18), 8151; https://doi.org/10.3390/app14188151 - 11 Sep 2024
Cited by 1 | Viewed by 1338
Abstract
The railway is an essential source of logistics and transportation in cold regions, but low temperatures and icing can be challenging for uninterrupted railway operations in these regions. Icing on railway switches is a safety hazard, and presently, one of the industry’s adaptive [...] Read more.
The railway is an essential source of logistics and transportation in cold regions, but low temperatures and icing can be challenging for uninterrupted railway operations in these regions. Icing on railway switches is a safety hazard, and presently, one of the industry’s adaptive approaches for ice mitigation is the use of resistive heaters. This method is efficient but consumes a great amount of electricity, leading to high financial costs in terms of the operation and maintenance of railway tracks in ice-prone regions. In this paper, a study is carried out using experiments and computational simulations to analyze the heat distribution in a cross-section of a rail at below-freezing temperatures. Experiments are performed in a cold room using an actual rail switch, thermocouples, and infrared imaging, while numerical analyses are carried out using a MATLAB-based analytical model to simulate the heat transfer, considering a section of stock rail and a heating element. Results show a considerable loss of heat from the heater to the surroundings of the rail, especially towards the ground ballast. Numerical simulation results provide a good insight into heat transfer along railway sections, and results are validated with experiments, where a good agreement is found. This study provides a good base for further optimization of resistive heating operations for ice mitigation along railway switches. Full article
(This article belongs to the Special Issue Fluid Flow and Heat Transfer: Latest Advances and Prospects)
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18 pages, 5217 KiB  
Article
Effect of the Particle Size Distribution of the Ballast on the Lateral Resistance of Continuously Welded Rail Tracks
by Jafar Chalabii, Morteza Esmaeili, Dániel Gosztola, Szabolcs Fischer and Majid Movahedi Rad
Infrastructures 2024, 9(8), 129; https://doi.org/10.3390/infrastructures9080129 - 6 Aug 2024
Cited by 5 | Viewed by 1985
Abstract
While the effect of ballast degradation on lateral resistance is noteworthy, limited research has delved into the specific aspect of ballast breakage in this context. This study is dedicated to assessing the influence of breakage on sleeper lateral resistance. For simplicity, it is [...] Read more.
While the effect of ballast degradation on lateral resistance is noteworthy, limited research has delved into the specific aspect of ballast breakage in this context. This study is dedicated to assessing the influence of breakage on sleeper lateral resistance. For simplicity, it is assumed that ballast breakage has already occurred. Accordingly, nine granularity variations finer than No. 24 were chosen for simulation, with No. 24 as the assumed initial particle size distribution. Initially, a DEM model was validated for this purpose using experimental outcomes. Subsequently, employing this model, the lateral resistance of different particle size distributions was examined for a 3.5 mm displacement. The track was replaced by a reinforced concrete sleeper in the models, and no rails or rail fasteners were considered. The sleeper had a simplified model with clumps, the type of which was the so-called B70 and was applied in Western Europe. The sleeper was taken into consideration as a rigid body. The crushed stone ballast was considered as spherical grains with the addition that they were divided into fractions (sieves) in weight proportions (based on the particle distribution curve) and randomly generated in the 3D model. The complete 3D model was a 4.84 × 0.6 × 0.57 m trapezoidal prism with the sleeper at the longitudinal axis centered and at the top of the model. Compaction was performed with gravity and slope walls, with the latter being deleted before running the simulation. During the simulation, the sleeper was moved horizontally parallel to its longitudinal axis and laterally up to 3.5 mm in static load in the compacted ballast. The study successfully established a relationship between lateral resistance and ballast breakage. The current study’s findings indicate that lateral resistance decreases as ballast breakage increases. Moreover, it was observed that the rate of lateral resistance decrease becomes zero when the ballast breakage index reaches 0.6. Full article
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19 pages, 22993 KiB  
Article
Water Resistance of Acrylic Adhesive Tapes for Rooftop Fastening
by Klára V. Machalická, Petr Sejkot, Miroslav Vokáč, Petr Pokorný and Vera Obradović
Buildings 2024, 14(6), 1636; https://doi.org/10.3390/buildings14061636 - 3 Jun 2024
Cited by 1 | Viewed by 1141
Abstract
Rooftop solar modules are usually held in place by racks or frames that are mechanically attached to a roof structure and/or by heavyweight, ballasted footing mounts. These mounts ensure that the panel system remains in position against wind load. However, mechanical connectors create [...] Read more.
Rooftop solar modules are usually held in place by racks or frames that are mechanically attached to a roof structure and/or by heavyweight, ballasted footing mounts. These mounts ensure that the panel system remains in position against wind load. However, mechanical connectors create penetrations into the water-resistant layer of the roof, whereas ballasted footing mounts cause a significant additional load on the load-bearing structure of roof. For these reasons, adhesive connection seems to be a beneficial solution. Acrylic adhesive tapes, marked as VHBTM, may provide sufficient strength, and they have no need for mechanical fasteners or ballast. Acrylic adhesive tapes also provide a comfortable, fast, and efficient bonding process with no curing compared to liquid adhesives. On the other hand, resistance to water at load-bearing joints has not been sufficiently studied yet and could be critical for connections exposed to the outdoor environment. The present study aims at the determination of water resistance and durability of the VHBTM tapes from the GPH series, which are typically used to bond a variety of substrates including many metals. The mechanical properties and failure modes are compared for the specimens before and after a 21-day immersion in water. A significant reduction in strength was observed, depending on the substrate material. The study of chemical changes in the acrylic tape and in its leachate through infrared spectroscopy (FT-IR), X-ray fluorescence, and X-ray diffraction analyses clarified the reduction in mechanical properties. The selected VHBTM tape demonstrated strong resistance to the effects of water. However, the overall strength of the joint after immersion was significantly impacted by the decrease in adhesion to a specific substrate. Full article
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24 pages, 6480 KiB  
Article
Trim and Engine Power Joint Optimization of a Ship Based on Minimum Energy Consumption over a Whole Voyage
by Yanyun Yu, Hongshuo Zhang, Zongbao Mu, Yating Li, Yutong Sun and Jia Liu
J. Mar. Sci. Eng. 2024, 12(3), 475; https://doi.org/10.3390/jmse12030475 - 10 Mar 2024
Cited by 12 | Viewed by 2538
Abstract
Trim optimization is an available approach for the energy saving and emission reduction of a ship. As a ship sails on the water, the draft and trim undergo constant changes due to the consumption of fuel oil and other consumables. As a result, [...] Read more.
Trim optimization is an available approach for the energy saving and emission reduction of a ship. As a ship sails on the water, the draft and trim undergo constant changes due to the consumption of fuel oil and other consumables. As a result, the selection of the initial trim is important if ballasting or shifting liquid among the tanks is not considered during a voyage. According to the characteristics of ship navigation and maneuvering, a practical trim optimization method is proposed to identify the Optimal Trim over a Whole Voyage (OTWV) which makes the fuel consumption of the voyage minimum. The calculations of speed vs. draft and trim surfaces are created according to hull resistance data generated by CFD, model tests, or real ship measurements, and these surfaces are used to calculate the OTWV. Ultimately, a trim and Main Engine (ME) power joint optimization method is developed based on the OTWV to make the total fuel consumption minimum for a voyage with a fixed length and travel time. A 307000 DWT VLCC is taken as an example to validate the practicality and effect of the two proposed optimization methods. The trim optimization example indicates that the OTWV could save up to 1.2% of the total fuel consumption compared to the Optimal Trim at Initial Draft (OTID). The trim and ME power joint optimization results show that the proposed method could steadily find the optimal trim and ME power combination, and the OTWV could save up to 1.0% fuel consumption compared to the OTID in this case. Full article
(This article belongs to the Special Issue Advances in Ships and Marine Structures)
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25 pages, 5601 KiB  
Article
Enhancing Railway Track Stabilization with Epoxy Resin and Crumb Rubber Powder-Modified Cement Asphalt Mortar
by Sang-Yum Lee, Young-Man Yun and Tri Ho Minh Le
Polymers 2023, 15(22), 4462; https://doi.org/10.3390/polym15224462 - 19 Nov 2023
Viewed by 2044
Abstract
This research investigates the quantitative impact of incorporating epoxy resin and crumb rubber powder (CRP) into cement asphalt mortar (CAM) for railway track stabilization. The study reveals significant improvements in various key parameters compared to conventional CAM. The modified CAM exhibits a 12.7% [...] Read more.
This research investigates the quantitative impact of incorporating epoxy resin and crumb rubber powder (CRP) into cement asphalt mortar (CAM) for railway track stabilization. The study reveals significant improvements in various key parameters compared to conventional CAM. The modified CAM exhibits a 12.7% reduction in flow time, indicative of enhanced flowability, and a substantial 62.4% decrease in the mixing stability gap, demonstrating superior mixing stability. Additionally, the modified CAM displays remarkable early-age compressive strength, with increases of up to 15.3% compared to traditional CAM formulations. Importantly, the modified CAM showcases robust resistance to challenging environmental conditions, with only a 6.7% strength reduction after exposure to sulfuric acid, highlighting its acid resistance, and exceptional freeze–thaw resistance, with a mere 1.5% strength reduction after undergoing six cycles. In a mock-up test simulating real-world conditions, the modified CAM effectively prevents ballast layer settlement, underscoring its potential to enhance the durability of railway track infrastructure. These quantitative findings not only endorse the practical feasibility of epoxy resin and CRP-enhanced CAM but also suggest its potential to contribute significantly to railway track longevity, reduce maintenance expenditures, and ensure operational reliability. Full article
(This article belongs to the Section Polymer Applications)
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16 pages, 6195 KiB  
Article
Three-Dimensional Numerical Analysis and Operational Optimization of High-Efficiency Sedimentation Tank
by Zhian Ye, Shaoxin Kang, Zhengjiang Wang, Qi Jiang, Jiangtao Zhang, Bin Zheng and Jinlei Wang
Water 2023, 15(20), 3656; https://doi.org/10.3390/w15203656 - 18 Oct 2023
Cited by 2 | Viewed by 2954
Abstract
The high-efficiency sedimentation tank has a wide range of application prospects in industrial wastewater treatment due to its small footprint, strong resistance to shock loads, and high efficiency. However, the complex flow field distribution inside significantly affects the treatment performance of the high-efficiency [...] Read more.
The high-efficiency sedimentation tank has a wide range of application prospects in industrial wastewater treatment due to its small footprint, strong resistance to shock loads, and high efficiency. However, the complex flow field distribution inside significantly affects the treatment performance of the high-efficiency tank. In this study, a three-dimensional geometric model of the high-efficiency sedimentation tank was constructed based on an engineering prototype. The corresponding solid–liquid two-phase, whole-process computational fluid dynamics (CFD) model for the high-efficiency sedimentation tank was established using the realizable k-ε turbulent model and the multiple reference frame (MRF) method. The internal structures of the flocculation zone, plug-flow zone, and clarification zone were optimized, and then the influence of operational process conditions on the flocculation treatment performance was investigated. The results indicate that, for the given engineering model, the average turbulent kinetic energy k in the flocculation zone exhibits a trend that initially increases and then decreases with the increase in the diameter and height of the draft tube. The optimal hydraulic conditions for the flocculation zone are achieved when the diameter of the draft tube is 2.5 m and the height is 3.5 m. The average turbulent kinetic energy dissipation rate in the plug-flow/clarification zone tends to decrease first and then increase as the height of the water tunnel and water-retaining weir increases. The optimal hydraulic conditions for the plug-flow and clarification zones are achieved when the height of the water tunnel is 1.0 m and the height of the water-retaining weir is 1.6 m. Under optimal operating conditions (dosage of dense media particles: 40 mg/L, stirring rate: 30 rpm, and inlet velocity: 0.72 m/s), satisfactory overall hydraulic conditions can be achieved throughout the entire high-efficiency sedimentation tank. Comparisons between a high-efficiency settling tank and a conventional clarifier for the treatment of circulating water sewage in a practical implementation reveals that the ballasted high-efficiency settling tank has advantages in terms of high hydraulic loading, high removal efficiency of hardness, small footprint, and low doses of flocculant. This research will provide reference values for the design and operation optimization of high-efficiency sedimentation tanks. Full article
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15 pages, 7046 KiB  
Article
Design and Analysis of the High-Speed Underwater Glider with a Bladder-Type Buoyancy Engine
by Dae-Hyeong Ji, Jung-Han Lee, Sung-Hyub Ko, Jong-Wu Hyeon, Ji-Hyeong Lee, Hyeung-Sik Choi and Sang-Ki Jeong
Appl. Sci. 2023, 13(20), 11367; https://doi.org/10.3390/app132011367 - 16 Oct 2023
Cited by 1 | Viewed by 2297
Abstract
This study entailed the design and analysis of a 400 m class underwater glider operated by a bladder-type buoyancy engine. The underwater glider was designed for high-speed movement with a maximum velocity of 2 knots. The shape of the hull was designed to [...] Read more.
This study entailed the design and analysis of a 400 m class underwater glider operated by a bladder-type buoyancy engine. The underwater glider was designed for high-speed movement with a maximum velocity of 2 knots. The shape of the hull was designed to reduce water resistance using the Myring hull profile equation. The reliability was verified by performing simulations using resistance coefficients. The relationship between the control value of the ballast discharged from the buoyancy engine and the glider’s speed according to the path angle was analyzed. Further, the relationship between the optimal glide angle and the design control value of the ballast was derived, and the optimal glider speed was estimated accordingly. Based on the analysis results, a bladder-type buoyancy engine was developed, and the maximum speed of the tested underwater glider was measured via sea trials. Full article
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16 pages, 11311 KiB  
Article
Optimal Shape Design of Concrete Sleepers under Lateral Loading Using DEM
by Jafar Chalabii, Majid Movahedi Rad and Seyedsaber Hosseini
Buildings 2023, 13(7), 1574; https://doi.org/10.3390/buildings13071574 - 21 Jun 2023
Cited by 4 | Viewed by 2259
Abstract
Despite the significant contribution of sleepers to the lateral resistance of ballasted tracks, limited research has focused on improving the shape of sleepers in this aspect. This study aims to evaluate proposed sleeper shapes based on the B70 form, utilizing a linear optimization [...] Read more.
Despite the significant contribution of sleepers to the lateral resistance of ballasted tracks, limited research has focused on improving the shape of sleepers in this aspect. This study aims to evaluate proposed sleeper shapes based on the B70 form, utilizing a linear optimization algorithm. First, a DEM model was verified for this purpose using the outcomes of the experiments. Then, using this model, the effect of the weight of the B70 sleeper was carried out on lateral resistance. Next, suggested shapes contacted with ballast materials were applied to lateral force while maintaining the mechanical ballast’s properties until a displacement of 3.5 mm was achieved. The current study’s results showed that the rate of lateral resistance increasing becomes lower for weights higher than 400 kg. Additionally, it was demonstrated that the sleeper’s weight will not always increase lateral resistance. The findings also indicated that although some proposal shapes had higher lateral resistance in comparison to other forms, these designs are not practical from an economic standpoint. Furthermore, despite the lower weight of some other suggested shapes in comparison with B70, the lateral resistances are 31.2% greater. As a result, it is possible to recommend employing a proposed sleeper rather than a B70 sleeper. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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17 pages, 5234 KiB  
Article
Effect of Random Lateral Ballast Resistance on Force-Deformation Characteristics of CWR with a Small-Radius Curve
by Huan Wang, Chengwei Xing and Xiaohui Deng
Materials 2023, 16(7), 2876; https://doi.org/10.3390/ma16072876 - 4 Apr 2023
Cited by 4 | Viewed by 1704
Abstract
To address the randomness of lateral ballast resistance in the field and its effect on the force-deformation behavior of Continuous Welded Rail (CWR) with small-radius curves, field tests were first conducted to investigate longitudinal and lateral ballast resistance on a 250 m-radius curve. [...] Read more.
To address the randomness of lateral ballast resistance in the field and its effect on the force-deformation behavior of Continuous Welded Rail (CWR) with small-radius curves, field tests were first conducted to investigate longitudinal and lateral ballast resistance on a 250 m-radius curve. It was found that the lateral ballast resistance follows a normal distribution based on the Shapiro–Wilk test. A finite element model of a small-radius curve CWR track was then established based on actual field conditions, and the force-deformation characteristics were analyzed under thermal loading. The results showed that it is of great significance to incorporate the randomness of the lateral ballast resistance as the deformation mode is closer to the actual field situation. In particular, attention should be given to areas where the lateral ballast resistance is weak. The research presented here has significant implications for railway maintenance practice. Full article
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17 pages, 6566 KiB  
Article
Influence of Guardrails on Track–Bridge Interaction with a Longitudinal Resistance Test of the Fastener
by Kaize Xie, Weiwu Dai, Hao Xu and Weigang Zhao
Appl. Sci. 2023, 13(6), 3750; https://doi.org/10.3390/app13063750 - 15 Mar 2023
Cited by 2 | Viewed by 2649
Abstract
The guardrail is an indispensable part of ballasted track structures on bridges. In order to reveal its influence on the track–bridge interaction of continuous welded rail (CWR), the longitudinal resistance model of the guardrail fastener and its influential factors are established through tests. [...] Read more.
The guardrail is an indispensable part of ballasted track structures on bridges. In order to reveal its influence on the track–bridge interaction of continuous welded rail (CWR), the longitudinal resistance model of the guardrail fastener and its influential factors are established through tests. By taking a continuous girder bridge (CGB) for railways as an example, a stock rail-guardrail-sleeper-bridge-pier integrated simulation model is developed. The effects of the guardrails, installation torque of the guardrail fastener, and joint resistance of the guardrail under typical conditions are carefully examined. The research results indicate that the nominal longitudinal resistance of the guardrail fastener and the elastic longitudinal displacement of the rail prior to sliding approximately grow linearly with the growth of the installation torque. The presence of a guardrail can alleviate the track–bridge interaction in the range of the CGB, but exacerbate the interaction near the abutment with moveable bearings. This fact enables the abutment position to be considered as a new control point for the design of CWR on bridges. Considering the changing rules of the rail longitudinal force and rail gap, it is recommended that the installation torques of the guardrail fastener and guardrail joint are 40–60 N·m and 700–800 N·m, respectively. The recommended maximum longitudinal stiffness of piers for CGBs is evaluated. When the longitudinal stiffness of the pier for a CGB is lower than the recommended value, the influence of the guardrail can be neglected in the design of the CWR. Full article
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