Search Results (122)

Train-induced ground vibrations can propagate into pile foundations, potentially causing undesirable vibration in nearby buildings, laboratories housing vibration-sensitive equipment, and manufacturing facilities for high-precision processes. This paper presents an innovative method for predicting building vibration from free-field ground vibration measurements at locations away from the tracks during train pass-bys. The proposed method accounts for site-specific soil profiles and train-soil-pile-structure interactions and is implemented in four steps. In Step 1, train-induced vibration transmission into the ground is estimated using an axisymmetric finite element model that simulates wave propagation through layered soils from the tracks to free-field ground locations. Step 2 estimates free pile head vibration using a three-dimensional finite-element model that captures the ground-borne transmission of track inputs through soil layers to the pile. Step 3 estimates vibration at the junction of the pile head and depot column base using a finite-element model to estimate the pile head impedance and an analytical impedance model for the depot structures supported by the pile. In Step 4, estimates of column-base vibration that transmits into over-track buildings are compared to measured column-base vibration levels obtained during train pass-bys. The method was applied at a metro depot in China, where tracks were in close proximity to columns supporting over-track buildings. Ground and column base vibration levels were measured during multiple train pass-bys. The estimated vibration levels at the base of depot columns closely agreed with the measured vibration levels at the columns during six-car train pass-bys. It demonstrated the potential effectiveness of this hybrid method for assessing vibration transmission into structures atop existing railway tracks. By integrating field measurements, finite element simulations, and analytical impedance models, the proposed hybrid method provides a framework for evaluating the transmission of the train-induced vibration to nearby building structures. Full article

Operational Technology (OT) and Industrial Control Systems (ICSs) along the NATO-EU eastern flank face escalating hybrid threats, yet existing cyber-resilience metrics remain IT-centric, lacking OT-specific constraints and geopolitical exposure dimensions. This paper presents a Design Science Research contribution: the development and simulation-based feasibility demonstration of two interconnected artefacts. The first is the AI-enabled Cyber-Resilience Index (ACRI)—a composite 0–100 metric operationalized through 16 indicators across four domains (detection performance, operational continuity, governance maturity, supply-chain risk), aggregated as a three-term convex combination of capability domains with a linear subtractive supply-chain exposure penalty, weighted via AHP-based illustrative sector-reference profiles. The second is the Unified Compliance Framework (UCF), a structured R → C → E → SLO mapping linking 47 atomic regulatory requirements (NIS2, DORA, CER, AI Act, CRA) to standards (IEC 62443, ISO/IEC 27001) and auditable evidence artifacts, with a Continuous Assurance Loop operationalizing continuous control monitoring. Feasibility is demonstrated through digital twin simulation under three OT-representative threat scenarios (energy SCADA APT, railway supply-chain compromise, manufacturing ransomware). Results in simulated environments show ACRI improvement from Moderate-Risk baselines (45–61) to Adequate-Resilience thresholds (65–73); the proposed federated autoencoder–LSTM detector attains a composite $D_{perf}$ of 0.883 versus 0.510 for a static ±3$\sigma$ threshold baseline (a 73% relative improvement at the domain level). Sensitivity analysis confirms classification robustness ($\pm 7.3\%$ weight perturbation; coefficient of variation below 9.1% across 10,000 Monte Carlo iterations). Critical limitations are explicit: simulation-only evidence ($n=12$ scenario instances), illustrative (non-empirical) AHP weights, no operational field validation, and limited inferential statistical power. instances), illustrative (non-empirical) AHP weights, no operational field validation, and limited inferential statistical power. The contribution is positioned as a proof-of-concept design artifact establishing methodological foundations for OT-centric resilience assessment and compliance-to-engineering traceability, not as a field-validated operational system. Full article

Additive manufacturing through a laser cladding has been shown to be an effective technology for the mitigation of wear and rolling contact fatigue (RCF) of railway track. Small-scale tests have consistently shown that creating a thin layer of premium material on the tribo-active surface of the railhead vastly reduces wear and suppresses the onset of RCF due to the ratcheting mechanism being almost eliminated in comparison to standard rail material. Cladding reduces material plastic flow by 60% which is a cause of insulated track joint failure. This paper reports results from the first full-scale trials of additively manufactured laser clad layers on railway rails by studying their mechanical properties and microstructure. This is a vital step in safely progressing this technology from lab scale to network application. Tested full-scale insulated block joint (IBJ) specimens, clad with martensitic stainless steel (MSS) and Stellite 6, were sectioned, polished and etched and the microstructures of the clad, heat-affected zone and parent rail materials were inspected using optical and scanning electron microscopy (SEM) (Hitachi TM3030 plus, Tokyo, Japan). Residual stress was also measured. Cladding with MSS and Stellite 6 showed high wear and RCF resistance after the tests. Material flow was reduced with the clad layer applied. No defects such as porosity or large precipitates were observed in the heat-affected zone (HAZ), particularly close to the rail surface at the clad end which could act as a point of weakness. Residual stress states varied between materials, MSS being compressive (−344 MPa average) and Stellite 6 being tensile (+391 MPa average) which could have an impact on the fatigue life of the clad. This finding matches previous work, indicating that MSS may be preferable in the field, where bending of rails can occur. Overall, the work showed that laser cladding can provide a good solution to lipping issues and wear problems of rail in IBJs. Analysis in this work confirmed that the HAZ where clad meets the bulk rail at the surface has good structural integrity; however, this needs to be a focus of attention in field application of these layers. Full article

Ensuring the structural integrity and service reliability of railway wheels has become a key challenge in modern manufacturing and maintenance strategies within the railway sector. In this context, Eddy Current (EC)-based Non-Destructive Testing (NDT) provides an automated and efficient approach for detecting surface and near-surface defects, while reducing inspection time and operator dependency compared to conventional manual methods. This study presents the integration of an EC inspection system into a precision lathe, enabling in-machining evaluation during wheel turning. Experimental validation was conducted on wheels with artificial defects, yielding high signal-to-noise ratios and enabling reliable defect characterization. Furthermore, computationally efficient and easily deployable machine learning algorithms were developed to enable automatic defect detection, localization, and size estimation. The results confirm the feasibility of in-machine EC inspection during machining operations, enabling early defect detection and contributing to safer, more efficient, and higher-quality manufacturing processes in the railway sector. Full article

The structural integrity of bogie frames is a critical factor in the safety and reliability of railway rolling stock, requiring advanced assessment methods to handle complex, multi-axial stress states. This research presents a robust numerical framework for the preliminary fatigue evaluation of a metro bogie frame, integrating high-fidelity Finite Element Analysis (FEA) with the Findley multi-axial fatigue criterion. The methodology overcomes the limitations of traditional uniaxial verification methods by employing a localized critical plane approach, implemented through a proprietary computational code. The investigation simulates a realistic operational scenario by superimposing a static vertical load of 15 tons per side with dynamic components derived from on-track accelerometric data. This integrated loading condition enables a precise reproduction of the “rotating” stress states typically encountered in service. Global structural analysis identified critical transverse welded joints as high-stress concentration zones, which were then subjected to a detailed multi-axial investigation. By correlating the extracted stress tensors with the resistance category included in the reference standard, over a regulatory life of 10 million cycles, a maximum cumulative damage index of 0.4602 was recorded. The results demonstrate that while the frame possesses adequate structural reserves, nearly half of its fatigue life is consumed in localized nodes. This methodology provides a reliable and computationally efficient tool for the structural health monitoring and development of innovative railway geometries, offering a superior predictive capability that remains scarcely utilized by major rolling stock manufacturers. Full article

Vibrations have long been a critical subject of investigation across engineering disciplines. With the expansion of major manufacturing sectors such as shipbuilding, automotive engineering, aerospace, and railway transport, the challenges associated with noise, environmental impact, and geotechnical stability have become increasingly complex. Mechanical systems inherently dissipate energy through vibration, and this dissipation can significantly influence structural performance, durability, and operational efficiency. Since the early foundational studies on vibration control in the 1980s, substantial progress has been made in developing innovative mitigation techniques. Among these, the acoustic black hole (ABH) concept has emerged as a promising passive method for reducing vibrational energy without adding significant mass. Over the years, researchers have further enhanced ABH structures by incorporating damping layers, which improve their ability to dissipate energy and control structural vibrations. More recently, scientific interest has shifted toward understanding the role of embedded or dispersed particles in vibration attenuation. Particle-based approaches have shown potential for improving energy dissipation mechanisms through micro-scale interactions, yet the underlying physical processes and their influence on vibration behavior remain active topics of research. In this study, we examine the influence of particles on vibration reduction through combined experimental and numerical investigations. The system is subjected to repeated excitation forces of 1 V, 2 V, and 3 V across frequency ranges of 10–1000 Hz and 10–2000 Hz. Two structural models, ABH-ABH and ABH, were considered, with particles embedded at the mid-plane of each configuration. Additionally, sinusoidal translational motion was analyzed at frequencies between 550 and 625 Hz, with a displacement velocity of 0.5 m/s, to determine the loss factor damping. The numerical results show consistent trends with experimental measurements, reinforcing the effectiveness of particle-enhanced ABH structures in vibration control. Full article

This paper investigates the coordination between logistics and policy decisions for electric vehicle (EV) exports under the Belt and Road Initiative. Focusing on the two modes—maritime shipping and the China Railway Express (CR Express)—along with government production subsidies, import tariffs, and service premium, a Stackelberg game model for a cross-border supply chain comprising a domestic manufacturer and an overseas retailer is constructed. The equilibrium outcomes under four scenarios formed by combining subsidy policies and transportation modes (Models NM, NR, GM and GR) are compared theoretically and numerically, with further evaluation of capacity constraints and power structures, as well as the robustness verification of the core findings. Results show that the CR Express mode exhibits a service-driven nonlinear cost pattern, where its service premium amplifies positive market responses. Its appeal to the manufacturer, however, is tightly constrained by fixed cost. Furthermore, government subsidies can overcome this barrier by synergizing with the service premium, turning the CR Express into a relatively advantageous strategy. Moreover, subsidy efficacy is conditional, depending heavily on the service premium level and logistics cost coefficient, leading to a proposed differentiated subsidy framework. This study offers a theoretical basis for corporate logistics strategy and targeted policy design. Full article

This study presents a comprehensive structural optimization workflow for a railway motor bogie frame, aimed at developing an innovative and lightweight design compliant with the reference European standards. The methodology integrates a two-stage topology optimization process, supported by an extensive numerical simulation campaign and a dedicated sensitivity analysis to identify the most critical load scenarios. In the first optimization stage, a global evaluation of the frame performance revealed that increasing the number of optimization parameters leads to a rise of approximately 50% in solver iterations. Symmetry constraints proved essential for simplifying both the optimization and the subsequent geometric reconstruction. The minimum feasible feature dimension strongly affected the final solution, modifying the material distribution and enabling a mass reduction of about 18%. The second optimization stage, focused on the cross beams, highlighted the relevance of manufacturing constraints in guiding the solver toward practical configurations. Static and fatigue assessments confirmed stress distributions consistent with the original frame, providing designers with a reliable basis for future material upgrades. Finally, the dynamic analysis showed a first natural frequency above 60 Hz, with variations in the first eigenvalue within 1% and preservation of the local flexural mode shape, ensuring full compatibility with the original frame interfaces and enabling seamless replacement with the optimized configuration. Full article

The study investigates the combined effects of material selection, manufacturing constraints, and a dynamic stress constraint function on the resulting material distribution achieved through a structural optimization process, while ensuring full compliance with the relevant European assessment standards for railway bogie. A high-fidelity finite element model of the complete bogie system was developed to accurately reproduce the operational loads and the structural interactions between the motor support and its surrounding components. The proposed methodology integrates topology optimization within a manufacturability-oriented framework, enabling a systematic evaluation of the influence of material properties, draw direction, and minimum feature size on the optimized configuration. In this context, an adaptive stress coefficient, derived from the performance of the original component, was introduced and proved effective in improving both the material distribution and the resulting stress levels of the optimized design. The results demonstrate that the combined consideration of material selection, manufacturing constraints, and adaptive stress control leads to a structurally efficient and production-feasible design. Three different materials were tested, showing consistent stress distributions and mass savings across all cases. The innovative optimized configuration achieved over 16% mass reduction while maintaining admissible stress levels. The proposed approach provides a generalizable and standard-compliant framework for future applications of topology optimization in railway engineering. Full article

Magnetic Barkhausen noise (MBN) represents a powerful non-destructive testing and material characterization methodology enabling quantitative assessment of microstructural features, mechanical properties, and stress states in ferromagnetic materials. This comprehensive review synthesizes recent advances spanning theoretical foundations, sensor design, signal processing methodologies, and industrial applications. The physical basis rooted in domain wall dynamics and statistical mechanics provides rigorous frameworks for interpreting MBN signals in terms of grain structure, dislocation density, phase composition, and residual stress. Contemporary instrumentation innovations including miniaturized sensors, multi-parameter systems, and high-entropy alloy cores enable measurements in challenging environments. Advanced signal processing techniques—encompassing time-domain analysis, frequency-domain spectral methods, time–frequency transforms, and machine learning algorithms—extract comprehensive material information from raw Barkhausen signals. Deep learning approaches demonstrate superior performance for automated material classification and property prediction compared to traditional statistical methods. Industrial applications span manufacturing quality control, structural health monitoring, railway infrastructure assessment, and predictive maintenance strategies. Key achievements include establishing quantitative correlations between material properties and stress states, with measurement uncertainties of ±15–20 MPa for stress and ±20 HV for hardness. Emerging challenges include standardization imperatives, characterization of advanced materials, machine learning robustness, and autonomous system integration. Future developments prioritizing international standards, physics-informed neural networks, multimodal sensor fusion, and wireless monitoring networks will accelerate industrial adoption supporting safe, efficient engineering practice across diverse sectors. Full article

We are witnessing a global commitment to sustainable mobility that requires advanced materials and manufacturing techniques, such as fused filament fabrication (FFF), to create lightweight, durable, and recyclable machine components. Acknowledging that friction and wear significantly contribute to energy loss globally, developing high-performance polymeric materials with customizable properties is essential for greener mechanical systems. FFF inherently drives resource efficiency and offers the geometric freedom necessary to engineer complex internal structures, such as the gyroid pattern, enabling substantial mass reduction. This study evaluates the tribological performance of FFF-printed thermoplastic polyurethane (TPU 82A) specimens fabricated with three distinct gyroid infill densities (10%, 50%, and 100%). Ball-on-disc testing was conducted under dry sliding conditions against a 100Cr6 spherical ball, with a constant normal load of 5 N, resulting in an initial maximum theoretical Hertz contact pressure of 231 MPa, over a total sliding distance of 300 m. Shore A hardness and surface roughness (R_a) were also measured to correlate mechanical and structural characteristics with frictional response. Results reveal a non-monotonic relationship between infill density and friction, with a particular absence of quantifiable mass loss across all samples. The intermediate 50% infill (75.9 ± 1.80 Shore A) exhibited the peak mean friction coefficient of $\overline{\mu }=1.002$ (${\mu }_{\max }=1.057$), which can be attributed to its balanced structural stiffness that promotes localized surface indentation and an increased real contact area during sliding. By contrast, the rigid 100% infill (86.3 ± 1.92 Shore A) yielded the lowest mean friction ($\overline{\mu }$ = 0.465), while the highly compliant 10% infill (44.3 ± 1.94 Shore A) demonstrated viscoelastic energy damping, stabilizing at $\overline{\mu }$ = 0.504. This work highlights the novelty of using FFF gyroid architectures to precisely tune TPU 82A’s tribological behavior, offering design pathways for sustainable mobility. The ability to tailor components for low-friction operations (e.g., μ ≈ 0.465 for bushings) or high-grip requirements (e.g., μ ≈ 1.002 for anti-slip systems) provides eco-efficient solutions for automotive, railway, and micromobility applications, while the exceptional wear resistance supports extended service life and material circularity. Full article

Railway barrier drives are key components of railway infrastructure and have a direct impact on traffic safety. Many of the commonly used drives are mechanical EEG-type barrier drives. EEG is a commercial designation of level-crossing gate drives produced by one of the Polish railway signalling equipment manufacturers, currently known as Alstom ZWUS Polska Sp. z o.o. (Katowice, Poland). These drives are characterized by their simple design and low cost, but limited efficiency and durability. Operational experience shows particular problems with the operation of this type of drive in winter conditions. This article presents an analysis of the impact of the selection of electric motors on the efficiency and reliability of level crossing drives. In addition to discussing the classic design with a PRMOa90-90 motor, commonly used in EEG drives, two proprietary solutions are presented: a commutator motor with rectangular neodymium magnets and a brushless DC motor (BLDC). Key operating parameters such as energy efficiency, starting torque, durability, maintenance requirements, and costs were compared. The results of the analyses indicate that the use of motors with neodymium magnets and BLDC solutions can significantly increase the efficiency and reliability of barrier drives, with each variant presenting a different profile of advantages and limitations. Full article

The rolling process is one of the most efficient methods for manufacturing long products with both regular and more complex cross-sectional shapes, the latter requiring the development of geometrically complex roll passes. Railway rails are one such product, manufactured at ArcelorMittal Poland S.A., Huta Królewska plant. During the rolling process, the roll passes are subject to wear due to several concurrent phenomena, such as mechanical fatigue, abrasive wear, and thermal fatigue. The determination of roll wear can be based on the experience of personnel and statistical data from previous production runs. It is also possible to determine roll wear through numerical modelling using Archard’s wear model. The aim of this paper is to define a methodology for the quantitative and qualitative determination of roll wear, as well as to establish a wear coefficient dependent on the type of plastic forming process. This will enable the development of a new roll pass design for railway rails that takes into account the durability of the roll passes. Full article

Within contemporary railway engineering, manufacturers of rolling stock are increasingly focused on developing vehicles that combine reduced weight with enhanced reliability. This objective is largely motivated by the need to decrease energy demand and limit environmental impact, encouraging the integration of innovative materials and cut-ting-edge design strategies. The growing use of multilayer composite materials in the railway sector stems from their unique combination of high strength and low weight, making them particularly suitable for structural applications. This study investigates the structural performance and optimization of a hybrid car body system composed of an aluminum frame integrated with multilayer composite panels. A fully automated computational framework has been developed to generate and assess all possible stacking sequence permutations of the laminate plies, coupled with a high-fidelity finite element model of the car body. The methodology enables the evaluation of failure indices, including Maximum Stress, Tsai–Wu, and Interlaminar criteria, across a wide design space. A comprehensive assessment of both mechanical and dynamic performance has been carried out according to relevant railway standards, supporting the robustness and reliability of the proposed optimization framework. The results confirm the capability of the methodology to efficiently identify and compare multiple laminate configurations while maintaining compliance with structural and modal requirements. The optimized configurations demonstrated maximum Tsai–Wu values below 0.9, first-mode frequency variations below 0.5% and potential mass reductions of 25–45% on the selected components. This approach provides a powerful and versatile tool for the rapid optimization of lightweight hybrid structures in railway applications. Full article

High-speed rail (HSR) makes a significant contribution to green innovation (GI), thereby supporting high-quality economic development. However, prior studies have mainly focused on the impact of HSR on regional innovation, ignored the influence on GI from the micro perspective, as well as the mechanism through which HSR affect GI. Using the data from manufacturing companies listed in Shanghai and Shenzhen stock exchanges during the period of 2004 to 2023, we treat HSR as a quasi-natural experiment and employ a multi-period difference-in-difference (DID) approach to explore the effect of HSR on GI. The regression results are presented as follows. (1) HSR significantly enhances GI in enterprises, and the results still hold after several robust checks. (2) HSR has a greater impact on the improvement of GI in lightly polluting SOEs of developed cities. (3) The mechanism by which HSR can improve GI is to promote the mobility of talent and alleviate financing constraints faced by enterprises. The policy recommendation is to focus on the heterogenous effect on GI in enterprises to promote the ability of sustainable development. Full article