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The formation of surface irregularities during electrode calendering remains a critical challenge. Specifically, uncoated regions of current collectors often develop severe wrinkles while coated areas frequently exhibit undesirable corrugations. Although controlling material tension has long been considered an effective strategy to address these defects, improper tension management can paradoxically lead to foil rupture or increased wrinkling severity, both result in elevated production waste. To address that, this work first explores the connection between the front/back tension intensity and the wrinkle and corrugation of the electrode via experiments and an analytical model. Results indicated that coated area corrugations were primarily influenced by the differential tension between processing stages rather than absolute tension values. For instance, reducing tension differential from 5N to 20N led to a significant 34.2% reduction in corrugation tortuosity. However, excessively large tension differences caused linear increases in shear displacement (δ), exacerbating wrinkling in the uncoated regions. After that, a novel pre-calendering process was proposed by applying compressive loading specifically to the current collector foil via a modified upper roller. Experimental results demonstrated an optimal defect reduction was achieved with both improved surface uniformity in the uncoated collectors and reduced corrugation severity in the coated area.

Light gauge elements for integrated beams were used, and thin webs are typically needed in constructed beams’ economical design. However, the buckling problem may arise if the Web is fragile. This risk may be reduced by using thicker panels, web reinforcements, or web enhancements. The use of corrugated Web is a possible means of achieving adequate rigidity and shear resistance without hardeners. Analytical studies were conducted in this present work to study the bending behavior of the conventional beam and light-weight steel beam with corrugated, concrete enclosed Web. Analyzes of finite elements have been conducted using the ANSYS beam software. The results present the capacity for load carrying and the deformation of the concrete-covered corrugated web beams. This study’s main objective is to acquire a better knowledge of a concrete embedded steel beam’s behavior.

Rail corrugation is a phenomenon of great diversity but appears now to be substantially understood. This review proposes some differences in classification of the phenomenon to take account of work undertaken since a widely cited review was published by Grassie and Kalousek in 1993, it attempts to fill holes in an overall understanding of the problem, and answers questions that remained open in 1993 and several that have arisen since. All types of corrugation that have been documented to date are essentially constant-frequency phenomena. By treating the vehicle—track system in its entirety, treatments are proposed that impinge upon track and vehicle design as well as upon the wheel—rail interface where corrugation appears. There is no neat solution to rail corrugation, but it can be treated comprehensively and in many cases also prevented by using products that are already commercially available. Since the frequency of common wavelength-fixing mechanisms varies roughly in the range 50—1200 Hz, trains travelling at different speeds can produce corrugation of substantially similar wavelength by different mechanisms in different locations. Although historical data can no longer be checked, this is the most likely explanation of the belief that rail corrugation was a substantially constant-wavelength phenomenon.

Rail corrugation is a serious problem in a railway transportation system, aggravating the operational risk and shortening the lifetime of train–track system. In order to ensure the safety and reliability of the railway system, the detection of rail corrugation is very important. Thus, this study systematically summarizes the recent research progress of rail corrugation. First, this study introduces the definition of rail corrugation and the classification criteria. Then, the formation mechanism of rail corrugation is analyzed in detail, and its adverse consequences are investigated. Further, this study summarizes several main detection methods, which are corrugation-detection methods based on acceleration measurements, wavelet transform methods for corrugation evaluation, computer-vision-based methods for corrugation automatic detection, digital filtering algorithms for rail corrugation detection, and others. In this study, the formation mechanism and detection methods of rail corrugation are systematically described, and various corrugation-detection methods are also introduced in detail. This study not only provides a scientific basis for railway maintenance, but also lays a solid foundation for future experimental design and data analysis. This study can also guide engineering practice to improve the reliability and safety of railway systems. It also provides useful experience for future railway-engineering design and planning, as well as safer and more reliable operation. In general, this study can provide technical support for the detection of rail corrugation to ensure the safety of the rail–track system.

By establishing vehicle-track space coupled model and rail corrugation evaluation model, the generation mechanism of rail corrugation was analyzed in frequency domain and time domain, and development characteristics of corrugation were studied by using corrugation growth rate. Analysis based on frequency domain: through modal analysis and frequency response analysis on the finite element model of track structure, it is found that there are natural frequencies of track structure close to measured corrugation passing frequencies. It shows that the vibration modes corresponding to these frequencies can be more easily excited, which can cause the resonance phenomenon of track structure and form the rail corrugation at corresponding frequencies. Analysis based on time domain: the time-history curves of rail vertical vibration acceleration and rail vertical displacement are calculated by using vehicle-track coupled model and the frequency domain transformation of the time-history data is carried out. It is found that there are characteristic frequencies close to the measured corrugation passing frequencies, which indicates that the vibration of track structure at corresponding frequencies is an important reason to promote the formation of corrugation. The change of vehicle speed has no effect on characteristic frequencies of corrugation growth rate curves, which reflects the fixed frequency characteristic of corrugation. With the increase of train operation times, the corrugation corresponding to characteristic frequencies will gradually form and develop, and the increase of vehicle speed will increase the wavelength range and development speed of rail corrugation.

This paper presents the results of a comprehensive assessment of the manufacture of pipes with corrugated inner surface. It examines the technological force, the stressed and deformed states, the probability of defects during corrugation of the pipe at different depths with the help of a rotating working mandrel and the plastic deformation caused by it. The analysis was performed using special QForm software. The study provides the graphs of force, distribution of stress and strain intensity and the probability of defects occurring in the part during corrugation.

Vertical bending vibration modes and rail wave propagation, including the damping characteristics, are the factors that cause rail corrugation. However, the ability to identify actual railways has been limited because of the huge number of sensors required for field tests. In this study, a novel and field-applicable method for identifying rail vibration modes and wave propagation characteristics is developed by multipoint hammering and the reciprocity theorem instead of multipoint measuring. Additionally, the proposed method is applied to an actual rail with a direct fastening track system on a bridge that has corrugation with a wavelength of approximately 0.04 m. As a result, the wavelength (wavenumber)-, group velocity-, and distance damping (attenuation) frequency relationship of the wave propagation is clarified in addition to the rail frequencies and mode shapes up to approximately 1500 Hz, including the pinned-pinned mode. Finally, the identified wavelength-frequency relationships and the measured rail irregularity can empirically demonstrate that the generated corrugation on the rail is produced by wave interference on the two axles in the bogie.

In this paper, an intelligent method to diagnose rail corrugation based on signal decomposition and entropy theory is proposed. The axle box acceleration signals are first decomposed into several components with different frequency bands by ACMP, EEMD and MODWT. By comparison, ACMP is able to successfully extract rail corrugation component from original signal without mode mixing. Energy entropy is then introduced here to quantify the degree of the rate of energy concentration. The analysis results show that the energy will change when rail corrugation occurs and the entropy will become small. It has been also proved that the entropy difference of rail corrugation and normal signal based on ACMP is the most significant. In addition, to intelligently diagnose rail corrugation, we combine energy entropy with energy index and the first mode energy, regarded as the input feature vector of LSSVM, to distinguish rail corrugation from mass data sets. It is obvious that the accuracy of ACMP-based technique is the highest.

The arc-shaped corrugated diaphragm is the packaging component of pressure sensors, and the quality of diaphragms directly affects the performance of pressure sensors. Diaphragms are usually produced by blanking process. Common production defects include the severe warping and the insufficient forming height. In order to reduce production defects, this paper uses the flat punch and the corrugated punch as research objects to clarify the effect of production process and punch structure on diaphragm production quality. The results show that the production process causes the diaphragm to have a convex warping tendency, which is opposite to the warping tendency caused by corrugation. Moving the corrugation away from the center of the diaphragm and increasing the corrugation spacing can improve the diaphragm quality, while the effect of the corrugation height can be ignored.

Short pitch corrugation has been a problem for railways worldwide over one century. In this paper, a parametric investigation of fastenings is conducted to understand the corrugation formation mechanism and gain insights into corrugation mitigation. A three-dimensional finite element vehicle–track dynamic interaction model is employed, which considers the coupling between the structural dynamics and the contact mechanics, while the damage mechanism is assumed to be differential wear. Various fastening models with different configurations, boundary conditions, and parameters of stiffness and damping are built up and analysed. These models may represent different service stages of fastenings in the field. Besides, the effect of train speeds on corrugation features is studied. The results indicate: (1) Fastening parameters and modelling play an important role in corrugation formation. (2) The fastening longitudinal constraint to the rail is the major factor that determines the corrugation formation. The fastening vertical and lateral constraints influence corrugation features in terms of spatial distribution and wavelength components. (3) The strengthening of fastening constraints in the longitudinal dimension helps to mitigate corrugation. Meanwhile, the inner fastening constraint in the lateral direction is necessary for corrugation alleviation. (4) The increase in fastening longitudinal stiffness and damping can reduce the vibration amplitudes of longitudinal compression modes and thus reduce the track corrugation propensity. The simulation in this work can well explain the field corrugation in terms of the occurrence possibility and major wavelength components. It can also explain the field data with respect to the small variation between the corrugation wavelength and train speed, which is caused by frequency selection and jump between rail longitudinal compression modes.