Search Results (311)

This work presents the application of a Time-Domain Reflectometry (TDR) inversion algorithm for localizing water along a bi-wire cable acting as a distributed sensing element (SE), and for evaluating the uncertainty of the water position measurement. The TDR inversion relies on a simplified yet effective gray-box circuital model of the measurement system that, without attempting a full-wave electromagnetic (EM) simulation, reproduces with good accuracy any actually observed reflectograms. The model parameters are estimated from a single acquired reflectogram so as to reproduce the measured signal, without a prior EM characterization of the system components. The model provides the water localization and enables extensive simulation campaigns under realistic variations in water position, stimulus pulse duration, and disturbance effects. A specific measurement setup, designed to perform repeated measurements in controlled laboratory conditions, is analyzed in detail as a case study. The water localization error of the measurement system is statistically evaluated in terms of confidence intervals, bias, and standard deviation, by means of simulated measurements of the model, with different water positions and TDR pulse durations. Then, the uncertainty evaluation is validated through 45 actual measurements, using multiple SEs, and the same water positions and pulse durations. The work proves the viability and the performance of the presented TDR inversion method for both localization measurements and for their uncertainty evaluation under different experimental conditions. More generally, it establishes a general framework for TDR measurements and uncertainty evaluation combining physical modeling, simulation-based uncertainty evaluation, and experimental verification. Full article

This study presents an investigation of the factors (driven by coupled multi-factor corrosion mechanisms) which contribute to the degradation of the spirally wound armored steel wires used to protect core-structured, unarmored optical-fiber submarine cables. The influences of the physical properties of deep-sea sediments on the durability of unarmored cables, as well as the impact of ionizing radiation on optical fibers, are also assessed. The objective of this paper is to establish a scientific basis for cable longevity by integrating theoretical insights with empirical evidence. Although the steel utilized in armored cables is cost-effective and durable, it remains vulnerable to corrosion. Since the inaugural practical deployment of submarine communication cables between the UK and France in the 1850s, only a small number of studies worldwide have examined the corrosion and durability of cable armor. There is also limited literature examining the physical characteristics of the deep-sea surface sediments that directly affect the service life of the cables’ mechanically fragile polyethylene sheathing. An in-depth analysis of the cable damage and environmental conditions observed during maintenance operations provides valuable insights into the key environmental factors that influence armor corrosion and cable longevity. This research aims to guide future design and support strategies to improve the sustainability and durability of cable systems in marine environments. Full article

With the rapid transition of power transmission systems toward higher capacity, longer distance, and improved efficiency, aluminum alloys from the 6xxx (Al–Mg–Si) and 8xxx (Al–Fe) series have become key structural materials for overhead conductors and power cables due to their low density, cost effectiveness, and favorable strength–conductivity balance. Compared with traditional steel-reinforced conductors, optimized aluminum alloy conductors can reduce structural weight by approximately 30–40% and installation cost by about 20–30%, while maintaining comparable current-carrying capacity. This review systematically focuses on modification methods and research progress of aluminum alloy cores for electric wires and cables. The strengthening characteristics of 6xxx alloys (heat-treatment responsiveness and precipitation strengthening) and the creep-resistance stability of 8xxx alloys are comparatively analyzed. Four core performance requirements—high electrical conductivity, mechanical strength, creep resistance, and corrosion resistance—are summarized as evaluation criteria for conductor applications. Particular emphasis is placed on three major modification strategies: (1) microalloying (e.g., Zr, Sc, rare earth elements) for precipitation and dispersoid stabilization; (2) thermomechanical process optimization for grain refinement and strength–conductivity balance; (3) composite reinforcement for high-temperature and ultra-high-strength applications. Quantitative literature data indicate that microalloying and process optimization typically achieve 15–40% strength improvement with conductivity variation within 3–5% IACS, while composite strategies may provide 30–80% strength enhancement but often at the expense of 5–20% conductivity reduction. The distinct applicability of 6xxx and 8xxx alloys under different service conditions is clarified, providing guidance for conductor material selection. Finally, future research directions—including precise composition–process integration, advanced thermomechanical control, and scalable modification technologies—are proposed to support high-performance, cost-effective, and large-scale deployment of aluminum alloy conductors. Full article

The paper presents SFPD, the new open algorithm developed by the University of Padova (PD in the acronym) for computing the steady-state regime due to any number of simultaneous faults (SF at the beginning of the acronym) both short circuits and open conductors. The algorithm does not have simplified hypotheses, since it benefits from the pre-fault regime based on PFPD_MCA (power flow by University of Padova with multiconductor cell analysis), a multiconductor power flow (developed and published by the first author) which takes into account both the active conductors (i.e., the phases subjected to the impressed voltages) and the passive conductors (i.e., the interfered metallic conductors, namely earth wires of overhead lines, metallic screens and armors of land and submarine cables, enclosures of gas insulated lines, return and earth wires of 2 × 25 kV AC high-speed railway supply system, etc.). Different types of faults are considered, and where they occur (also along the lines), by means of a suitable admittance matrix in phase frame of reference and embedded inside the overall network bus admittance matrix. Some comparisons with simplified approaches are presented in order to demonstrate the power of the method. Eventually, application to the real Italian network is comprehensively shown. Full article

(1) Background: Hospitalized preterm infants often require months of vital signs monitoring in the neonatal intensive care unit. Today, wired sensors are essential for survival, but are associated with numerous disadvantages including sensor dislocations, skin trauma and hygiene risks. Non-contact vital sign monitoring would therefore represent a significant improvement in the care of hospitalized neonates. (2) Objective: This study aims to lay the foundation for non-contact radar-based monitoring of the respiratory rate, which could be used in the neonatal intensive care unit. (3) Methods: We developed a radar-based vital parameter monitoring system for recording the respiratory rate of premature infants in a pediatric incubator. The novel system employs a four-channel I/Q FMCW radar with compact, application-specific antennas optimized to cover the defined area of interest on the infant’s thorax. As a proof-of-principle study, the system was tested in six anesthetized newborn piglets. (4) Results: Using the radar-based system, thorax movements were detected and the respiratory rate was calculated. We observed a high accordance between the signals of respiration detected by the novel radar sensor with the signals of the cable-bound monitor in resting piglets. (5) Conclusions: The novel radar sensor is suited for measuring respiration in the piglet model. In future, the sensor should be optimized in order to improve its robustness against disturbances body movements and in order to allow detection of heartbeat. Full article

Direct vehicle impacts on stay cables are less understood than vehicle–pier collisions, especially for anchorage damage and post-impact load transfer. This study investigates the dynamic responses of stay cables under vehicular impact through a combination of scaled physical tests. This test simulates real-world vehicle collision scenarios using an impact trolley. Two 1:5 inclined specimens (each a 19-wire galvanised steel bundle) were tested using a 1582 kg impact trolley travelling at 4.0 m/s in lateral and frontal conditions. Both tests showed a rapid rise in force to a dominant peak, followed by rebound oscillations and a long-tail decay, with no wire rupture. The lateral impact force peaked at around 241 kN at a displacement of approximately 230 mm. It then declined sharply while the deflection increased to around 268 mm, indicating that large deflections were governed by inertia. In contrast, the frontal impact force reached a maximum of almost 258 kN at a displacement of around 221 mm. However, it maintained higher post-peak forces, reaching approximately 106 kN at around 253 mm. This resulted in enhanced energy transfer. Maximum external work increased from about 20.7 kJ to about 25.2 kJ, and residual energy rose from about 25 percent to about 69 percent. Post-test inspection identified minor debonding near the anchorage exit as a vulnerability. Full article

Stay cables are critical load-bearing components in cable-stayed structures, making corrosion distribution vital for damage diagnosis and maintenance. To address the insufficient characterization of circumferential multi-point corrosion distribution in stay cables, a theoretical model of circumferential multi-point defect magnetic charge for the stay cables was established, and a self-magnetic flux leakage experiment was conducted on 37-wire steel specimens with circumferential corrosion. The effects of corroded wire number (N), corrosion time (T), and circumferential angle number (K) on the axial B_x component of the magnetic flux leakage signal were analyzed. The relationship between the θ-B_x-max peak distribution and corrosion patterns was clarified. Quantitative models for corrosion number (c), center (θ_c), and the cross-sectional corrosion rate (α) were established. The results indicate that c improves the determination of the number of concentrated corrosion sites in the ‘peak platform’ corrosion distribution type. Based on the Lorentz fitting, the maximum prediction error of θ_c is 15.1%, and the prediction accuracy of the cross-sectional corrosion rate α exceeds 90%. The study provides a reference for the quantifiable characterization and evaluation methods of the circumferential multi-point defect distribution in stay cables. Full article

Coaxial cable plays a vital role in the wide application of telecommunications, network, and television broadcasting and other fields, with its transmission performance directly affecting signal quality and transmission efficiency. In practical applications, the length of the cable and the terminal load state of the connection often affect the stability of the signal. In order to solve this problem, we used STMicroelectronics STM32F407VET6 (STMicroelectronics, Geneva, Switzerland) as the master controller in this system, and deduced the length of the cable by analyzing the functional relationship between the length of the cable and the open circuit frequency. An open cable is regarded as a capacitor, and any two core wires are regarded as two plates of a flat capacitor. The linear relationship between open frequency and length is used to detect the length of the coaxial cable. The system then determines whether the terminal load is capacitance or resistance based on the detected frequency. If no frequency is detected, then the load is considered resistance. The system detects the resistance value of the resistor through series voltage division. If a frequency is detected, this indicates that the load is capacitance. At this time, the system uses an RC oscillation circuit composed of HGSEMI ICL8038 (Huagao Semiconductor Co., Ltd., Wuxi, China) for testing, and provides the phase shift required by the corresponding signal through the RC network, so as to detect the capacitance value. Finally, we successfully designed a coaxial cable length and terminal load detection system based on STM32F407VET6. Through this system, the user can accurately understand the length of the coaxial cable and the load of the connection terminal, which provides a reliable guarantee for the stability of signal transmission. Full article

To address the limitations regarding poor adaptability to complex forest environments as well as high installation and operational costs in existing mountain transportation equipment, a modular cable-type equipment for moso bamboo transportation was designed based on the terrain characteristics of steep bamboo forests and specific transportation requirements. This study first presents the overall structure and working principle of the transportation equipment. Next, a theoretical analysis and component selection were conducted for critical parts such as the wire rope, supporting components, wire-rope-driven devices, and hydraulic systems. Then, the static characteristics of the supporting components and the vibration characteristics of the wire rope were simulated and analyzed. Finally, performance testing of the equipment was conducted, focusing on transportation productivity and machine utilization. The results showed that the maximum deformation of the supporting components was 1.75 mm, occurring at the lower roller–rail contact region. During unloading, the first-order principal vibration amplitude of the wire rope had the greatest impact at the mid-span position, with a value of 0.27 m. The vibration frequency of the wire rope during operation is influenced by the its initial tension, load mass, and attachment distance, with the first-order frequency range approximately between 0.85 and 3.90 Hz. Within this frequency range, the bouncing excitation caused by moso bamboo does not induce resonance in the wire rope. The transportation productivity of the equipment was 2.61 tons per hour, with the machine utilization rate exceeding 95%. This study indicates that the designed cable-type equipment effectively meets the requirements for moso bamboo transportation in complex forest environments. Full article

High-entropy alloy (HEA) coatings are widely recognized for their excellent hardness and wear resistance. Heterogeneous cabled wire welding (HCWW) combined with gas metal arc welding (GMAW) has emerged as an efficient approach for fabricating HEA coatings; however, severe arc instability inherent to HCWW often deteriorates coating quality. In this study, the effects of axial magnetic fields (AMFs) with different orientations on the HCWW–GMAW process were systematically investigated. High-speed imaging revealed that the HCWW arc without magnetic assistance exhibits pronounced instability, characterized by asymmetric morphology and rotational behavior. The application of AMFs significantly altered arc dynamics. An upward axial magnetic field (N-AMF, 2 mT) effectively suppressed arc rotation, resulting in a stable bell-shaped arc and more uniform heat input, whereas a downward axial magnetic field (S-AMF) caused arc contraction and promoted dendrite coarsening. Consequently, the N-AMF condition led to a refined and homogeneous microstructure, yielding a high microhardness of 825 ± 15 HV. Tribological tests demonstrated that the wear rate of the N-AMF-assisted coating was reduced by 55% compared with that produced by conventional GMAW. These results highlight that magnetic-field-induced arc stabilization plays a critical role in achieving high-performance HEA surface coatings. Full article

With the rapid development of high-speed railways, the dynamic performance of the pantograph–catenary system plays a crucial role in ensuring the safe and stable operation of trains. This study investigates the effect of the structural parameters of the pantograph–catenary system to achieve good dynamic interaction performance under high-speed conditions. A finite element model of the catenary system, incorporating nonlinear cable and truss elements, and a lumped mass model of the pantograph are developed. The penalty function method is employed to simulate the pantograph–catenary interaction. A total of 2187 dynamic simulations are performed, with seven variables—pantograph parameters, span length, contact wire tension, messenger wire tension, number of droppers, stitch wire length, and stitch wire tension. The comprehensive effect of these parameters is evaluated based on dynamic performance indicators, such as pantograph–catenary contact force, pantograph head lift, and support point lift. The results indicate that increasing the number of droppers, contact wire tension, and messenger wire tension enhances dynamic performance, while an increase in span length negatively affects performance. Stitch wire tension has little to no effect. Full article

Aluminum conductor cables are exposed to environmental conditions in service, where wind-induced vibrations generate multiaxial stresses and cause partial sliding between the stranded layers. Such dynamic loading can lead to fatigue or wear failure, particularly at the contact zones between wire layers. The influence of heat treatment and cold work on the wear of these aluminum wires remains unstudied. This work aims to evaluate the microabrasive wear of rolled and heat-treated 6201 aluminum alloy wires used in conductor cables. The wear tests were performed using free-ball microabrasive wear equipment and alumina (Al₂O₃) abrasive paste at a concentration of 0.40 g/mL of distilled water. The parameters used were as follows: 100 Cr6 steel balls with a diameter of 25.4 mm, sample inclination of 60°, normal force of 0.3 N, and shaft speed of 0.185 m/s or 280 rpm. The test time was set at 20 min, 30 min, 40 min, 50 min, and 60 min. The wear test data were processed using the Achard equation. The microabrasive wear test results indicate that the wear coefficient decreased by 19.1% after the artificial aging process, compared with the solution-treated alloy (95% CI: 15.5–22.3%), and this reduction was statistically significant (p < 0.001). After the combined treatment of rolling and artificial aging, the alloy had a drop in wear coefficient of 36.1% compared to the same solution-treated alloy (95% CI: 32.6–39.6%), representing the largest statistically significant improvement among the tested conditions (p < 0.001). Cold work (rolling) reduces the mobility of dislocations, requiring greater stress to deform the material, thereby increasing its stiffness and wear resistance. In this 6201 alloy, it is inferred that artificial aging led to the formation of Guinier-Preston zones, which evolved into the formation of metastable β” precipitates in needle-like form, coherent with the matrix. As the aging process progresses, the β’ particles evolve into larger β particles that are no longer coherent with the matrix. The combined processes of rolling and aging decrease the wear coefficient. Statistical analysis demonstrated that microstructural conditions explain approximately half of the total variability in the wear coefficient (η² = 0.495), indicating that the wear performance under the present experimental configuration is primarily governed by intrinsic strengthening mechanisms rather than experimental variability. Full article

This work focuses on evaluating the fatigue characteristics of a 66 kV wet-type submarine cable. The analysis incorporates realistic offshore environmental conditions and considers installation through a flexible pull-in system. The target system was deployed at the Southwest Offshore Wind Farm in Korea, where the structural response of the cable is governed by combined wave- and wind-induced loading. To determine the ultimate limit state (ULS) behavior of the cable arranged in the flexible pull-in installation configuration, a global dynamic analysis was initially performed, from which time-dependent displacement histories were extracted under site-specific metocean conditions. The results indicate that lateral wave-induced loading dominates the global response owing to the vertically suspended configuration of the flexible pull-in installation system. A detailed local fatigue analysis was performed based on the critical loading scenarios identified from the global analysis. Prior to the fatigue evaluation, a numerical modeling approach for the local analysis of the 66 kV wet-type submarine cable was developed and validated through comparisons with experimental tensile test results. The developed numerical model successfully captured the axial stiffness characteristics and deformation response of the cable, demonstrating a discrepancy of less than 1% between the numerical predictions and experimental measurements. Fatigue analyses were performed for 120 displacement-based time-history loading cases derived from the global dynamic response. The results show that the fatigue damage is predominantly concentrated in the steel-wire armor, particularly near the fixed boundary region, identifying it as the governing fatigue-critical component. In addition, a parametric study of the wire-armor helix angle revealed that increasing the helix angle significantly improved the fatigue life by enhancing the bending flexibility and reducing the stress concentration under transverse loading. These findings provide practical insights into the fatigue-resistant design and optimization of wet-type submarine cables installed using flexible pull-in installation systems in floating offshore wind applications. Full article

The hanging net shielding system, employing a suspended cage-type enclosed structure to restrict the high-voltage transmission wire, has seen increasingly widespread application in transmission line crossing construction. However, the lack of a comprehensive dynamic analysis methodology has limited the standardization of its design and usage. In this investigation, a systematical dynamic modeling and analysis procedure of the hanging net shielding system is proposed based on the absolute nodal coordinate formulation (ANCF). The carrier cable, slings and transmission wire are discretized by the ANCF cable element. The spatial flexible beam–beam contact model and the assumption of a single contact area are adopted to perform the contact searching between the transmission wire and the horizontal pulley. The system dynamics analysis equation is assembled and solved by generalized alpha method. A full-scale model is simulated for the transmission wire impact condition and the variation history of the tension in carrier cable and the sling cable are given. The peak value of the tension in carrier cable could be 110 kN, while the largest tension in sling cable is 9 kN. Results could help to ensure construction safety, shorten the design cycle of the protection system and reduce the development cost at the same time. Full article

In order to address the challenge of accurately identifying the extent of corrosion in parallel steel wire cables, a series of corrosion detection tests were performed on parallel wire bundles with varying degrees of corrosion. Following the collection of weak magnetic signals from a 12-channel Hall array, the influence patterns of corrosion severity on the distributions (B_x, B_z) of leakage magnetic signals were analysed. The experimental results were validated by means of a three-dimensional finite element model, leading to the proposal of a novel weak magnetic imaging method based on the fusion of adaptive threshold K and linear interpolation. The findings of the study demonstrate a strong linear relationship (R² = 0.998) between axial corrosion length and the peak-to-trough distance of the normal component B_z. Furthermore, it was determined that a positive correlation exists between the circumferential corrosion width and the circumferential distribution range of B_z. The utilisation of an adaptive threshold K for the purpose of threshold segmentation has been demonstrated to be an effective method for the delineation of corrosion boundaries, thereby enabling precise localisation. The present research provides technical support for the visualisation and quantitative assessment of cable corrosion. Full article