Wear-level-monitoring on electrical conductors with high-frequency alternating currents

In this paper, the mechanical damage behavior is investigated based on the characteristic roughness on the surface and the orientation of superficial structures. The main goal is to explore the surface roughness on mechanically loaded copper conductors as a lifetime indicator. For this purpose, copper conductors are mechanically stressed in accordance with EN 50,396 and then examined metallographically and microscopically. The microstructure examination shows that the roughness is caused by material extrusion and cracks due to work hardening in the surface area. Using confocal microscopy, it is shown for the first time that significant formation of surface roughness takes place over the service life of copper conductors. The roughness increases monotonically, but not linearly with number of cycles, due to internal microstructural processes and can be divided into three sections. First inspections of the conductor surface over lifetime show a correlation between the intensity of structures orientated 45° to the loading direction and the roughness. This phenomenon, already known from microscopic slip lines, is thus also evident in macroscopic roughness formation and is well founded by the research theory on material extrusion along dislocation lines. In summary, a lifetime determination is possible based on its developing roughness which enables the utilization as a sensor element. Graphical abstract

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“…Measurements with high-frequency alternating current are therefore further examined for in situ measurements. For more details, see [21].…”

Section: Intensity Of Surface Roughness Over Service Lifementioning

confidence: 99%

Surface roughness and its structural orientation caused by internal microstructural changes in mechanically stressed copper conductors

et al. 2022

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Wear-Induced Attenuation on Transmission Lines and Their Causes

Lenz

Baron

Wittmann

et al. 2022

Trans. Electr. Electron. Mater.

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In this paper, the radio frequency (RF) behavior of mechanically stressed coaxial and for the first time also twisted-pair transmission lines is investigated over their service life. The main goal is to enable predictive maintenance for cables in moving applications and avoid preventive replacement. This also reduces the use of high-cost resources. For this purpose, stranded and solid-core variants of coaxial and twisted-pair type cables are mechanically loaded on the two-pulley apparatus according to EN 50396. Their RF transmission (S21) behavior is measured using a vector network analyzer and presented over bending cycles. For the first time, the phase response of mechanically loaded transmission lines is evaluated with respect to their service life. Two significant causes for the increasing attenuation and altered phase response are identified: breakage in foil screen and increasing surface roughness on the copper conductors. The identified causes are supported with literature evidence. Through measurements and theoretical calculations, it is proven that the phase is much more suitable for an assessment of the remaining service life than the amplitude. The findings can be used to implement a cable monitoring system in industrial environments which monitors the lines in-situ and reminds the user to replace them, whenever a certain wear-level is reached.

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Integrity-Sensing Based on Surface Roughness of Copper Conductors for Future Use in Natural Fiber Composites

et al. 2021

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Wear-level-monitoring on electrical conductors with high-frequency alternating currents

Cited by 3 publications

References 4 publications

Surface roughness and its structural orientation caused by internal microstructural changes in mechanically stressed copper conductors

Surface roughness and its structural orientation caused by internal microstructural changes in mechanically stressed copper conductors

Wear-Induced Attenuation on Transmission Lines and Their Causes

Integrity-Sensing Based on Surface Roughness of Copper Conductors for Future Use in Natural Fiber Composites

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