Regarding that Ultraviolet radiation, pollutant adsorption, and environmental changes may be the main reasons for the aging and yellowing on windshield rubber in high-speed trains, countermeasures are proposed to solve the aging and yellowing of windshield rubber and reduce the adverse effects caused by rubber yellowing.

Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to test the yellowed windshield rubber. Aging tests, including UVaging, natural aging and salt spray aging, were conducted to analyze the effects of aging on the windshield rubber. Different cleaning agents were selected to soak the windshield rubber, and the quality, hardness, and surface appearance of the rubber samples were tested.

After UV aging, antioxidants migrated to the surface of the windshield rubber, but due to oxidation failure, they could not capture free radicals, leading to continued oxidation reactions within the material and resulting in yellowing of the rubber in a short period of time.

Cleaning agents have a minimal impact on windshield rubber, UV aging has the greatest impact and natural aging is a gradual and slow deterioration process. Through daily deep cleaning and maintenance with protective agents at regular intervals, the deterioration of windshield rubber yellowing in high-speed trains can be effectively suppressed.

The efficient utilization of recycled concrete powder (RCP) has attracted much attention. To break through the limitation of single activation technology of RCP, this study investigates the effects of a mechanical-microwave method on the reactivity of RCP.

The mechanical properties, hydration products, and pore structure of RCP-incorporated mortar were evaluated.

The results demonstrate that the combined activation reduces the median particle size of RCP and induces a low-frequency shift in the Si-O-T FT-IR characteristic peaks, signifying depolymerization of the silicate network and formation of highly reactive broken bond sites. Concurrently, decreased Si2p and Al2p binding energies in XPS spectra confirm enhanced surface reactivity. The 28-day strength activity index (SAI) of RCP mortar improved from 65.7 (untreated) to 82.2% under optimal activation conditions (90-min ball milling followed by 10-min microwave irradiation), outperforming solely mechanical activation by 3.6-6.1%. Furthermore, combined activation increased chemically bound water content from 22.8 to 33.7%, accompanied by a low-wavenumber shift in FT-IR peaks of hydration products. The total porosity of RCP mortar decreased from 17.2 to 14.6%, indicating a denser pore structure.

This study explores the feasibility and potential mechanism of mechanical-microwave activation of RCP, aiming to provide valuable insights for the sustainable development of materials. Using activated RCP in cement-based materials reduces the demand for cement and substantially cuts carbon emissions, thereby making a critical contribution to the construction industry's green and low-carbon transition.

This study aims to design and validate an emergency response method for high-speed railway earthquake early warning (EEW) systems based on the Propagation of Local Undamped Motion (PLUM) principle in order to enhance the timeliness and accuracy of warnings under seismic threats.

A hierarchical architecture of the railway EEW system was adopted, in which self-built stations along the railway serve as the backbone and the national seismic network provides supplementary data. Warning zones were designed along the railway using overlapping trapezoidal layouts to cover seismic stations and reduce inter-regional time delays. Offline replay experiments were conducted using 82 historical earthquake events and records from 61 seismic stations to evaluate the timeliness and accuracy of warning information.

The results indicate that the PLUM-based early warning method can issue emergency response information before destructive seismic waves arrive. Multiple earthquake experiments demonstrated high reliability and stability, with effective detection across different magnitudes and epicentral distances. Furthermore, the trapezoidal overlapping zone design improved regional consistency and significantly reduced missed alerts.

This work represents the first systematic application of the PLUM method to high-speed railway EEW in China. By integrating railway operational requirements, the proposed method provides a practical and robust emergency response strategy, offering new insights into seismic risk mitigation for China's high-speed railways.

This study examines the effect of increased surface energy on adhesion strength. Surface modifications were made using chemical coating methods such as primer paint (primer) and cataphoresis (KTL, Kathodische Tauchlackierung). The wetting behaviour of adhesive on these surfaces and the resulting contact angles were analysed to evaluate bonding effectiveness.

Primer paint was applied to glass fibre reinforced plastic (GFRP) materials and cataphoresis coating was applied to steel. Contact angles of the coated surfaces were measured and compared to those of the uncoated (natural) surfaces.

Results showed that applying primer to GFRP and KTL to steel increased their surface energy compared to untreated surfaces. A decrease in contact angle correlated with improved wetting, suggesting enhanced adhesion potential.

While the effects of surface coatings on adhesion have been studied, there is limited research specifically on the adhesion-enhancing potential of KTL coatings. Typically used for corrosion resistance, KTL is shown here to also improve adhesion. The novelty lies in experimentally demonstrating KTL's dual role as both a protective and adhesion-enhancing layer.

This study aims to carry out optimization and improvement work on the artificial climate aging and ultraviolet aging tests of elastic expansion joints in railway concrete bridges.

Three polyurethane elastomer specimens with different chemical compositions were adopted. According to relevant standard regulations, the aging test process was analyzed and evaluated in detail, and reasonable improvement suggestions were put forward. The effectiveness was verified through actual tests.

The final test results indicate that the combination of artificial climate aging tests and ultraviolet aging tests is technically feasible and has significant advantages in practical applications.

This study optimizes the conditions of artificial climate aging and ultraviolet aging tests, compares the advantages and disadvantages of different aging test methods, and proposes a combined test scheme of artificial climate aging and ultraviolet aging and verifies its effectiveness. The results provide valuable reference for simulating the actual aging behavior of polyurethane elastomers, material performance evaluation, and application in railway bridge engineering. It is conducive to promoting the reasonable application of this material in engineering, improving engineering quality, reducing costs, and has economic and social benefits.

For the commonly used concrete mix for railway tunnel linings, concrete model specimens were made, and springback and core drilling tests were conducted at different ages. The springback strength was measured to the compressive strength of the core sample with a diameter of 100mm and a height-to-diameter ratio of 1:1. By comparing the measured strength values, the relationship between the measured values under different strength measurement methods was analyzed.

A comparative test of the core drilling method and the rebound method was conducted on the side walls of tunnel linings in some under-construction railways to study the feasibility of the rebound method in engineering quality supervision and inspection.

Tests showed that the rebound strength was positively correlated with the core drill strength. The core drill test strength was significantly higher than the rebound test strength, and the strength still increased after 56 days of age. The rebound method is suitable for the general survey of concrete strength during the construction process and is not suitable for direct supervision and inspection.

By studying the correlation of test strength of tunnel lining concrete using two methods, the differences in test results of different methods are proposed to provide a reference for the test and evaluation of tunnel lining strength in railway engineering.

To address the encapsulation challenge of fiber Bragg grating (FBG) sensors in complex railway environments, this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term axle counting system monitoring.

Wheel-rail mechanical behavior was simulated via finite element analysis (FEA) to determine optimal sensor placement. A clip-on composite sensor was subsequently engineered. Stress transduction efficacy was validated through FEA quantification of stress responses at the axle counter location. Findings - The proposed FBG axle counter integrates temperature compensation and anti-detachment monitoring as well as advantages such as simplified installation with minimal maintenance and sustained operational reliability. It effectively transmits stress, yielding a measured strain of 39 μe under static loading conditions without sensitivity-enhancing elements.

This study performs FEA of wheel-rail stress distribution and engineers the dual-slot composite sensor, FEAwas conducted to quantify the stress magnitude at the axle sensor position of the dual-slot composite sensor. Additionally, FEA was performed on sensors with different structural configurations, including adjustments to the axle sensor position, number of slots and axle position. The results confirmed that the designed composite sensor exhibits superior stress transfer characteristics.

Type-120 relief valves are critical components of locomotive braking systems, and they rapidly discharge the air pressure during brake release to enable swift pressure relief. In order to develop type-120 relief valve rubber diaphragms with long life and high performance, the damaged faulty samples were analyzed and studied.

Finite element analysis (FEA) was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions. The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests, and its suitability for the modeling of large deformations was confirmed.

The FEA results indicated that, when the rubber diaphragms reached their maximum deformation, the peak stress on their upper surfaces was 5.44 MPa. Thus, this region is highly susceptible to fatigue damage. The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.

This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.

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 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.