This research aims to investigate how the adhesion performance of GFRP composite components, commonly used in railway vehicles, is affected when bonded to cataphoresis coated steel substrate surfaces.

In this context, the aim was to determine the optimal adhesion parameters for bonding GFRP samples with natural and primed surfaces to steel samples with cataphoresis coatings. Then, single-lap joint samples with different bond thicknesses of 1 mm, 2 mm and 3 mm were prepared. Finally, tensile tests were performed on the samples.

The results showed that GFRP specimens with natural surfaces, characterised by the highest surface roughness, exhibited the lowest bond strength. But, the highest bonding performance was achieved in specimens where primed GFRP was bonded to cataphoresis coated steel, especially with a bond thickness of 1 mm, and achieving a yield strength of 20 MPa. This situation explains the characteristic difference between surface roughness and chemical coating, which are two essential pre-treatments in adhesive bonding. While surface roughness provides mechanical interlocking, excessive roughness can hinder the adhesive's wetting ability, causing it to remain suspended on the surface as described in the Cassie-Baxter theorem. In contrast, it has been observed that, despite low surface roughness, chemical coatings enhance the bonding between primer paint and adhesive molecules, and - as stated in the Wenzel theorem - improve the surface wettability.

As a preliminary preparation in the adhesive method, primer paint is applied to steel surfaces and GFRP material surfaces in classical industrial applications. In this research, the application of the catapheresis process to the steel substrate instead of primer paint and the bonding of primer-painted GFRP materials to this surface make a unique contribution to the research.

This paper aims to analyze the transverse vibration characteristics of the high speed train window glass when passing through tunnel.

The lateral vibration acceleration response of glass chamber of high-speed train CR400BF-A on Beijing - Chengdu high-speed railway was tested at different speeds through the tunnel entrance, exit, tunnel interior, Tunnel Group and rendezvous time in the tunnel, the lateral distribution characteristics of vibration frequency and vibration power amplification coefficient of glass of high-speed train were analyzed.

The results show that: The vibration of the high-speed train glass increases significantly during the tunnel, and the amplitude of vibration acceleration in the tunnel is significantly higher than outside the tunnel as the travel speed increases; the amplitude of lateral vibration acceleration of the glass of a high-speed train does not vary with changes in tunnel length and is not affected by the aerodynamic effects of the tunnel when traveling inside the tunnel, but its vibrations create noticeable fluctuations during variations when encountering oncoming traffic; The vibration characteristics of the high-speed train glass are forced harmonic vibrations, the excitation frequency does not vary with travel speed and travel position changes inside and outside the tunnel. The lateral vibration acceleration of the glass of a high-speed train is applied vertically and uniformly to the glass surface as an "inertial force" and creates a cyclic bending vibration stress that can easily lead to fatigue damage.

The research results provide guidance for the prevention of glass failure in high-speed trains.

This study aims to investigate the fatigue behavior and failure modes of bolted lap joints using Modified Tensile Specimens (MTS) under various cyclic load conditions. Emphasis is placed on identifying the relationship between load amplitude, fatigue life, and damage progression in low-carbon steel assemblies.

An experimental approach was adopted using MTS specimens fabricated from St 12 03 cold-rolled steel, joined with Grade 8.8 M4 bolts. Cyclic fatigue tests were conducted under zero-based loading at seven distinct force levels. Fracture surfaces were visually analyzed to identify dominant failure mechanisms.

The results revealed a strong inverse correlation between applied cyclic load and fatigue life. Three distinct failure modes were identified: bolt shear at high loads (5.4 kN), interface cracking and slippage at moderate loads (4.9-5.1 kN), and plate tearing or stable fatigue behavior at lower loads (=4.1 kN). The results highlight a progressive transition in failure mechanisms, from bolt shear at high loads to plate tearing and interface cracking at lower loads, providing essential insights for fatigue-resistant bolted joint design.

This study offers original insights into the fatigue behavior of bolted lap joints using MTS, a relatively underexplored configuration in fatigue assessment. By experimentally evaluating failure modes under varied cyclic load levels, the authors uncover critical transitions in damage mechanisms—from bolt shear to interface cracking and plate tearing—depending on the applied load. Unlike many existing studies focused on numerical modeling or bonded joints alone, this work provides empirical data rooted in real-world fastening conditions using cold-rolled low-carbon steel.

This study aims to propose a novel identification method to accurately estimate linear and nonlinear dynamics in permanent magnet synchronous linear motor (PMSLM) based on the time-domain analysis of relay feedback.

A mathematical model of the PMSLM-based servo-mechanical system was first established, incorporating the aforementioned nonlinearities. The model's velocity response was derived by analyzing its behavior as a first-order system under arbitrary input. To induce oscillatory dynamics, an ideal relay with artificially introduced dead-time components was then integrated into the servo-mechanism. Depending on the oscillations and the time-domain analysis, nonlinear formulas were deduced according to the velocity response of the servo-mechanism. Afterwards, the unknown model parameters can be solved on account of the cost function which utilizes the discrepancy between nominal position characteristics and temporary position characteristics, both of which are extracted from the oscillations. The proposed recognition method was validated through a two-stage process: (1) numerical simulation and calculation, followed by (2) real-time experimental verification on a direct-drive servo platform. Subsequently, leveraging the identification results, a novel control strategy was developed and its tracking performance was benchmarked against conventional control schemes.

Simulation results demonstrate that the proposed method achieves estimation accuracy within 8%. Building on this, a novel control strategy is developed by incorporating both friction pulsation and force pulsation identification results into the feedforward compensator. Comparative experiments reveal that this strategy significantly enhances tracking and positioning performance over traditional control schemes. In a word, this new identification method can be used in different process control and servo control systems. Moreover, parameter auto-tuning, feed forward compensation or disturbance observer can be investigated based on the obtained information to improve the system stability and control accuracy.

It is of great significance for the performance improvement of rail transit motor control equipment, such as electro-mechanical braking systems. By enhancing the efficiency of motor control, the performance of the product will be more outstanding.

This study aims to implement condition monitoring for urban rail train permanent magnet synchronous motors and inverter systems. Through the construction of a digital twin model, it performs fault diagnosis of potential system failures, enabling rapid fault localization and protection.

This research begins with a brief introduction to the structure and classification of permanent magnet synchronous motors (PMSMs), followed by a detailed analysis of their mathematical model. Subsequently, it thoroughly investigates the working principle of three-phase two-level inverters and the distribution of space voltage vectors. Based on the analysis of the main circuit topology, a digital twin model matching the external characteristics of the physical circuit is established using the model predictive control method, achieving accurate system simulation. Furthermore, through theoretical analysis and simulation verification of phase current characteristics under inverter switch tube faults, general patterns of phase currents under fault conditions are summarized. The established digital twin model is then employed to validate these patterns, confirming the model's effectiveness in fault diagnosis.

This study proposes a fault diagnosis method based on digital twins. Experimental and simulation results demonstrate that the established digital twin model can accurately simulate the external characteristics of the actual physical circuit, validating its effectiveness in inverter fault diagnosis. This approach offers practical value for condition monitoring in actual urban rail train systems.

The study innovatively starts from a mathematical model and simulates the actual physical model through a virtual model, requiring only external characteristics to achieve system fault diagnosis, thereby enhancing diagnostic efficiency.

Adding an appropriate pre-sag to the geometry of simple catenary systems for electric railways can improve their performance in dynamic interaction with the pantographs of trains operating under them. The value of pre-sag can be obtained by empirical approximation or computationally expensive optimisation. This study aims to define a simple but accurate method to determine a suitable pre-sag without dynamic simulations and to find its limitations.

A quasi-static method to determine the ideal value of pre-sag is described based on elasticity variations. It considers variations of the static contact force. The limits of this method are investigated by comparing it to a parametric dynamic simulation study. In the dynamic simulation, an optimal level of pre-sag is identified for each contact force level. The influence of the speed in the dynamic simulation results is expressed in two parameters: the quasi-static influence in the mean contact force and the dynamic influence in the ratio between the vehicle speed and the wave propagation speed in the contact wire.

The comparison between the suggested method and the dynamic simulations shows a high consistency up to a speed limit of around 40 % of the wave propagation speed. The best agreement with the dynamic results is achieved by calculating the optimal pre-sag based on the absolute elasticity variation.

The simplified approach for determining the pre-sag is valid for low-speed applications, such as suburban railway lines. For these cases, a highly suitable geometry can be obtained with the suggested method, meaning a significantly reduced computational effort. As a case study for this work, the results are applied to a Swedish suburban rail line upgrade case.

The static uplift force is added as a varied parameter in dynamic simulations. The shift in system behaviour from low to high dynamics is described, and how the benefits from pre-sag are visible and then disappear. The limit value of the low-dynamics regime is identified to be 40 %.

This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring. The purpose is to develop a reliable temperature compensation method for the system, improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.

Combined with theoretical analysis and experimental verification, the temperature compensation method is explored. The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula, the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived. The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.

The experimental results show that this method can reduce the error of the static level monitoring system by about 40 %. The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation, which has certain practicability.

The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method. The accuracy of the system is improved, which provides a reference for slope stability monitoring under complex environment (especially railway geotechnical engineering) and promotes the development of precision monitoring technology.

This paper focuses on studying the reliability allocation for the railway system, aiming to improve the overall reliability of the railway system and ensure safety operation.

In view of the complex structure of the railway system, involving many subsystems, this paper analyzes the close dynamic coupling effect between railway subsystems. Based on this, taking the railway system failure as the top event, a fault tree is constructed in this paper. Then, a reliability allocation method based on the fault tree is employed to allocate the reliability index. Finally, a numerical experiment is implemented to show the performance of the reliability allocation method.

The results showed that each subsystem needs to improve its reliability to meet the specified railway system reliability requirements, and the traction power supply system is the most important subsystem, which is the most efficient in improving the reliability of the railway system.

For the first time, starting from a holistic perspective of the system, reliability allocation is carried out based on the importance of each railway subsystem.