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Method for Detecting Defects in Switch rails Based on the Wavelet Baseline

IEEE SENSORS JOURNAL 2025年第4期25卷 6836-6849页

作者： Xu, Xining Liu, Wei Beijing Jiaotong Univ Sch Mech Elect & Control Engn Beijing 100044 Peoples R China CRRC Ziyang CO LTD Ziyang 641300 Peoples R China

Switch rail is an important basic component of rail transportation. Due to its variable cross section structure, there are many guided wave modes that can propagate inside it. When the ultrasonic guided wave is used to detect the defect of switch rail, the defect echo is often superimposed with complex background signal, which is difficult to extract. To solve the problem that the time-domain baseline method needs complex temperature compensation algorithm and is difficult to be applied in engineering, this article explores a new method from the frequency domain. The Fourier transform is applied to the waveguide signal and the FFT result of a waveguide signal from a nondefective switch rail is selected as the baseline. The difference of the FFT result between the waveguide signal and the baseline is calculated by the algorithm designed, being defined as a frequency-domain operator. The results show that the frequency-domain baseline method has a comprehensive identification rate of 99.89% and that no temperature compensation is required for indoor switch rail detection. Based on this, this article proposes the wavelet baseline method that integrates time-domain and frequency-domain analysis. The 3-D waveform data of the guided wave is transformed by wavelet, the difference between the data to be recognized and the baseline data is calculated based on the corresponding segments by the algorithm designed, and the frequency-time operator is obtained. For indoor datasets, the comprehensive detection rate of the wavelet baseline method is 99.93%, and the defect discrimination is better than that of the frequency-domain baseline method. For outdoor test data collected within 28 days, the comprehensive detection rate of the wavelet baseline method is 99.2%. The defect detection experiment of the switch rail on the actual line with the accessory structure is also carried out. The results show that the wavelet baseline method can effectively identify the defects of the switc

关键词： rails Switches Acoustics Temperature sensors Temperature distribution Defect detection Temperature measurement Wavelet transforms Sensors Time-domain analysis Semi-analytical finite element signal processing switch rail ultrasonic-guided wave

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Stochastic model of accelerated cooling of eutectoid steel rails

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MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING 2025年第2期33卷 025008-025008页

作者： Szeliga, Danuta Forys, Jakub Jazdzewski, Tomasz Kusiak, Jan Kuziak, Roman Nadolski, Rafal Oprocha, Piotr Pietrzyk, Maciej Potorski, Pawel Rauch, Lukasz Zalecki, Wladyslaw AGH Univ Krakow Fac Met Engn & Ind Comp Sci Al Mickiewicza 30 PL-30059 Krakow Poland AGH Univ Krakow Fac Appl Math Al Mickiewicza 30 PL-30059 Krakow Poland Upper Silesian Inst Technol Lukasiewicz Res Network Ul K Miarki 12 PL-44100 Gliwice Poland

The paper proposes a methodology for incorporating uncertainties of material behaviours in the microstructure evolution model for eutectoid steels. The stochastic model of phase transformations was developed. The model accounts for a random character of the nucleation of pearlite and bainite and the differential growth equations for these structural components are solved for the stochastic variables. The coefficients in the model were identified using inverse analysis for the results of dilatometric tests. The model was applied to simulations of the cooling of rails by subsequent immersions of the rail head in the polymer solution. Johnson-Mehl-Avrami-Kolmogorow phase transformations model was used to design the optimal cooling cycle. Histograms of the microstructural parameters for this optimal cycle were calculated using the developed stochastic model. It was shown that the probability distributions of the pearlite colony size, the nodule size, the interlamellar spacing and the hardness are asymmetric. The model predicted deviations of microstructural parameters and hardness from the mean values.

关键词： eutectoid steels rails controlled cooling phase transformations stochastic model uncertainty

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A Reconfigurable Auxiliary Circuit for Transient Enhancement in Processor Power Systems With Multiple Voltage rails

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2025年第6期72卷 6383-6392页

作者： Qian, Yijie Xu, Shen Wang, Xinru Li, Lingyun Sun, Weifeng Southeast Univ Natl ASIC Syst Engn Res Ctr Nanjing 210000 Jiangsu Peoples R China

This article proposes a practical auxiliary circuit for multiple voltage rails to improve dynamic response under significant load steps with an ultrafast slew rate. The proposed auxiliary circuit consists of a current injection/absorption circuit with nonlinear control that can effectively reduce undershoot and overshoot during transients, a sampling mechanism supporting its independent operation, and a reconfigurable energy path supporting multiple voltage rails. The proposed auxiliary circuit is illustrated and verified in a high-power supply system for processors with two voltage rails at different voltage levels, which effectively improves the dynamic response of both voltage rails and demonstrates robustness in fast alternating load steps without affecting regular operation. The maximum load step of 250 A with the current slew rate of 1250 A/mu s is tested, and the overshoot and undershoot are reduced by 36% and 25%, respectively, with recovery times less than 9 mu s. Compared with existing research and solutions, the proposed auxiliary circuit has cost and space savings advantages, better versatility to support a wide range of power supply types, and is easy to implement.

关键词： Voltage control Transient analysis rails Capacitors Threshold voltage Power system dynamics MOSFET Capacitance Switching converters Pulse width modulation Auxiliary circuit dynamic response nonlinear control reconfigurable energy path

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Advanced Under-rails Fiber-Optic Sensor for Detection of Rolling Stock and Axles in Tram Transport

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2025年 74卷

作者： Fajkus, Marcel Jargus, Jan Nedoma, Jan Kepak, Stanislav Krizan, Daniel Cubik, Jakub Krenzelok, Tomas Leal-Junior, Arnaldo Marques, Carlos VSB Tech Univ Ostrava Fac Elect Engn & Comp Sci Dept Telecommun Ostrava 70800 Czech Republic Prodin As Pardubice 53002 Czech Republic Univ Fed Espirito Santo Grad Program Elect Engn BR-29075910 Vitoria Brazil Univ Aveiro CICECO Aveiro Inst Mat Phys Dept P-3810193 Aveiro Portugal VSB Tech Univ Ostrava Dept Phys Ostrava 70800 Czech Republic

This article describes the implementation of an advanced fiber-optic intensity sensor for the comprehensive detection of axles and bogies of rail vehicles in tram transport. The sensor uses the principle of optical fiber bending, where the intensity of transmitted light is modulated due to mechanical stress on the fiber caused by the passage of a tram and the subsequent reversible deformation of the rail. The innovative design of the sensor allows for its easy installation under the rail foot, between the rail and the sleeper, replacing conventional anti-vibration pads, and includes specially designed deformable elements which the optical fiber bends and modulates the transmitted light intensity. During long-term testing (11 months in various weather conditions) conducted in the real tram depot (Ostrava, Czech Republic), 20602 tram passages were secured and analyzed. The sensor demonstrated success in detecting bogies, achieving 100% accuracy with no false positives (FPs) or false negatives (FNs). Axle detection showed an average success rate of 86.1%, with variability among different tram types up to 97.8%. The signal modulation was also subjected to detailed analysis, revealing differences in responses between various tram types, which can be attributed to differences in bogie construction and vehicle weight. Due to its electromagnetic immunity, the implemented fiber-optic sensor offers the potential for more reliable detection and broad application possibilities, including track occupancy monitoring, speed measurement, or determining the direction of travel on single-track lines. With slight optimization, the sensor could also be used to weigh rail vehicles or as an axle counter in railway or light rail transport.

关键词： rails Axles Optical fiber sensors Strain Rail transportation Optical fibers Monitoring Insulation life Degradation Temperature measurement Axles' detection bogies detection intensity fiber-optic sensor railway monitoring

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Structure, Phase Composition, and Dislocation Substructure Gradients in rails during Ultralong Operation

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RUSSIAN METALLURGY 2024年第2期2024卷 305-310页

作者： Kuznetsov, R. V. Gromov, V. E. Ivanov, Yu. F. Kormyshev, V. E. Shlyarova, Yu. A. Yur'ev, A. A. Siberian State Ind Univ Novokuznetsk Russia Russian Acad Sci Siberian Branch Inst High Current Elect Tomsk Russia AO EVRAZ Consolidated West Siberian Met Plant Novokuznetsk Russia

Modern physical metallurgy methods are used to study the structure, phase composition, dislocation substructure, and carbon redistribution in differentially quenched 100-m rails after extremely long operation (passed gross tonnage 1770 mln t since 2013). The laws of changing the main parameters, namely, the relative content of various morphological varieties of a structure, the scalar and excess dislocation densities, the volume fraction of cementite, and the redistribution of carbon atoms, are revealed in the cross section of the rail head along the central axis of symmetry and the radius of rounding of the fillet at distances of 0, 2, and 10 mm from the surface. The decrease in the volume fraction of the carbide phase in the surface layer of the head is assumed to be associated with decarbonization and the motion of carbon atoms to defects in the steel structure. The transformations along the central axis are found to proceed much more slowly as compared to the change relative to the fillet radius.

关键词： rails structure phase composition ultralong operation

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Evaluation of Mechanisms for Strengthening of Surface Layers of Long rails in Different Directions Under Continuous Operation

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RUSSIAN PHYSICS JOURNAL 2024年第8期67卷 1142-1149页

作者： Popova, N. A. Gromov, V. E. Potekaev, A. I. Nikonenko, E. L. Klopotov, A. A. Porfiriev, M. A. Kondratova, O. A. Borodin, V. I. Tomsk State Univ Architecture & Bldg Tomsk Russia Siberian State Ind Univ Novokuznetsk Russia Natl Res Tomsk State Univ Tomsk Russia Russian Acad Sci Siberian Branch Tomsk Sci Ctr Tomsk Russia

The structural-phase sates and defect substructure are studied by the method of transmission electron microscopy using diffraction at different distances from the wheel-rail contact surface along the central axis of symmetry of the top of rail (TOR) (rolling surface) and along the radius of rounding (fluting) of the differentially hardened rails of the DH400RK category made of hypereutectoid steel after their continuous service. Using the obtained structure parameters, the estimates are made of the hardening mechanisms (strengthening by pearlite component, incoherent cementite particles, grain- and subgrain boundaries, dislocation substructure and internal stress fields) controlling the yield stress in the steel under study. A comparison is performed of the quantitative fine structure parameters and the contributions into hardening on the rolling surface and fluting. It is found out that the prevailing morphological component near the wheel- rail contact surface is the subgrain structure, and in the fluting - strengthening by incoherent particles.

关键词： electron microscopy hypereutectoid steel rails fluting rolling surface phase composition fine structure parameters strengthening mechanisms

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Ultrasonic Testing of Railroad rails: Cold Temperature Effects and Considerations

IEEE OPEN JOURNAL OF INSTRUMENTATION AND MEASUREMENT

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IEEE OPEN JOURNAL OF INSTRUMENTATION AND MEASUREMENT 2024年 3卷

作者： Fadhil, Aqeel T. Washer, Glenn Poudel, Anish Yadav, Kalpana Shrestha, Survesh Univ Missouri Dept Civil & Environm Engn Columbia MO 65201 USA MxV Rail Res & Dev Dept Pueblo CO 81001 USA MxV Rail Dept Engn Serv Pueblo CO 81001 USA

The research presented in this article investigated the effect of low temperatures on acoustic properties in coupling fluid and rail steel. The study focused on the effect of low-temperature conditions on ultrasonic attenuation and velocity. The work introduces practical considerations for improving the quality of ultrasonic testing (UT) performed in cold weather. The study investigated common coupling fluids used in rail detector cars equipped with liquid-filled tires that house ultrasonic transducers. Velocity measurements of longitudinal waves propagating through the fluid and reflecting from a steel disc target were conducted. Steel properties were studied by fabricating two specimens from the head and Web of two different 136RE rail sections. Velocity of longitudinal waves and mode-converted shear waves as well as attenuation measurements were conducted in rail specimens with side drilled holes (SDHs) at different depths. The tests were performed in an ultrasonic immersion tank integrated with a heat exchanger and chiller bath to obtain the targeted test temperatures ranging from -50(degrees)C to+20(degrees)C. The coupling fluid test results showed a linear increase in the ultrasonic velocity as the temperature decreased with a rate that ranged from -2.70 m/s/degrees C to -1.83 m/s/degrees C for the tested fluids. The test results also showed increased velocity in rail steel with decreasing temperatures with an average rate of -0.65 m/s/degrees C for longitudinal waves and an average rate of -0.33 m/s/degrees C for shear waves. These results indicate that temperature-dependent velocities must be used to obtain the desired refraction angle and adjustments to amplitude-based acceptance criteria may be needed to ensure uniform acceptance/rejection capabilities across all potential inspection temperatures.

关键词： rails Acoustics Steel Fluids Attenuation Transducers Couplings Temperature measurement Testing Meteorology cold weather rail inspection temperature dependence ultrasonic testing (UT) velocity

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Formation of Gradient Structural-Phase States in the Head of Special-Purpose rails during Operation

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RUSSIAN METALLURGY 2024年第2期2024卷 298-304页

作者： Ivanov, Yu. F. Porfir'ev, M. A. Gromov, V. E. Kryukov, R. E. Shlyarova, Yu. A. Russian Acad Sci Siberian Branch Inst High Current Elect Tomsk 634055 Russia Siberian State Ind Univ Novokuznetsk 654007 Russia

The structure, phase composition, and dislocation substructure in the head of long differentially quenched special-purpose rails made of E90KhAF steel after a passed gross tonnage of 187 mln t are analyzed. The formation of flexural extinction contours is observed, which indicates an elastic-stressed state in the material. The sources of lattice curvature-torsion are found to be intra- and interphase boundaries, and the mechanisms of destruction of cementite lamellae are determined.

关键词： rails E90KhAF steel scalar dislocation density pearlite cementite

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Strengthening Mechanisms of rails' Surface in Ultra Long-Term Operation

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PHYSICS OF METALS AND METALLOGRAPHY 2023年第13期124卷 1509-1514页

作者： Kuznetsov, R. V. Gromov, V. E. Ivanov, Yu. F. Peregudov, O. A. Shliarova, Yu. A. Kormyshev, V. E. Semin, A. P. Siberian State Ind Univ Novokuznetsk 654007 Russia RAS SB Inst High Current Elect Tomsk 634055 Russia Omsk State Tech Univ Omsk 644050 Russia

The studies of structural phase state and defect substructure of head surface of 100-meter differentially quenched rails after extreme long-term service (passed tonnage of 1770 million gross tons) on experimental ring of the Russian Railways are carried out by means of the methods of transmission electron diffraction microscopy (TEM). The quantitative comparative analysis of strengthening mechanisms of tread surface and surface of working fillet is performed. It is shown that steel strength is a multifactor value and is determined by combined action of a number of physical mechanisms. The contributions caused by matrix lattice friction, internal stress fields, solid solution strengthening and pearlite constituent of steel structure are estimated. It is detected that for tread surface the main strengthening is provided by long-range stress fields and for fillet the main mechanism is a substructural one. A comparison is made between dependences of combined yield point on a distance to head surface and steel data before operation and after passed tonnage of 691.8 and 1411 million gross tons. The detected decrease in yield point at passed tonnage of 1770 million tons can be related to formation of fragmentary structure in surface layers due to transformation of subgrain low angle boundaries in large angle boundaries in extremely long operation.

关键词： surface rails structure phase composition strengthening mechanisms operation

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Analysis of Sliding Contact of Armature Inside the Vertical Curved rails in Electromagnetic Railgun

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IEEE TRANSACTIONS ON PLASMA SCIENCE 2023年第5期51卷 1357-1363页

作者： Che, Yunlong Yuan, Weiqun Yuan, Wu Wang, Zhizeng Hao, Wei Zhao, Ying Yan, Ping Chinese Acad Sci Inst Elect Engn Beijing 100190 Peoples R China Chinese Acad Sci Inst Mech Beijing 100190 Peoples R China

In previous studies, the armature-rail sliding contact interface is usually considered to be an ideal slide in which both rails are parallel and symmetric. However, due to the influence of structural deformation of the barrel affected by boundary constraints and the manufacturing errors of rails and armature, it often leads to a variety of nonideal the armature-rail matching such as space curved or twisted rails, offset or deflected armature, and so on. This article focuses on the common vertical curved rail in electromagnetic railgun. By introducing centrifugal force effects and coupling electromagnetic force, the armature-rail contact pressure is analyzed theoretically. According to the 3-D finite-element simulation results, the effect of centrifugal force on sliding contact pressure should not be ignored. The effects of different curved radii, velocities, and densities of armature on the contact pressure are compared and analyzed. The influence law on the contact pressure is obtained, which provides a theoretical basis for the design of the railgun.

关键词： rails Armature Force Mathematical models Electromagnetic forces Contacts Load modeling centrifugal force contact pressure curved rail railgun

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