Non-Destructive Testing of Aircraft Structures Using Microwire-Based Tensile Stress Sensor

Šmelko, Miroslav; Draganová, Katarína; Lipovský, Pavol; Semrád, Karol; Blišťanová, Monika; Kašper, Patrik

doi:10.3390/app10228218

Cited by 8 publications

(9 citation statements)

References 44 publications

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“…A discrete fast Fourier transform (DFT) can help analyze the frequency area in detail. Many measurements were made [17,27], mainly in the area of non-contact measurements, confirming the suitability of the method and the VEMA-041 magnetometer. The VEMA-041 is a purpose-built measuring device designed for the measurement of MFs [30][31][32] for the needs of military aviation.…”

Section: Experimental Methods and Experimental Equipmentmentioning

confidence: 81%

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Magnetic Fields of Devices during Electric Vehicle Charging: A Slovak Case Study

et al. 2021

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The aim of this contribution is to identify and quantify the magnetic field parameter (MP) devices for charging electric vehicles (EVs). An EV is a mobile device. The EV remains a mobile device even when it is charging in a fixed charging stand. ICNIRP and SBM standards apply to stable devices. A magnetic field (MF) creates local gradient fields that change cyclically over time near the charging stations. The rotating vector MF is a specific parameter. An MF is evaluated by its strength and spatial changes. The triaxial fluxgate magnetometer VEMA-041 was used for the measurements. The MF was observed in the frequency range of 0–250 Hz, and the magnetic induction density was from T 2 × 10−9 T to 2 × 10−5 T, with a sensitivity of 1.7 nT. The MF analysis was performed within the time and frequency range. The rotating vector MF was identified at the measurement points. Measurements were realized for the charge under the following parameters: cables, 600 A; transformer, 250 kVA (22 kV/400 V); a cab-fixed charging stand, and an AC/DC charger in the EV. EV charging was performed with 6.6 kW of power and 43-kW fast charging. The measured results were satisfactory, according to the ICNIRP and SBM 2015 standard. The values measured at a distance of 1 m from the wall of the transformer were BRMS < 2 µT. BRMS values <3 µT were measured in the space of the cable’s entry into the distribution box. EV values should not be assessed under this regulation. However, an EV is a mobile device. In the selected EV sample (a first-generation Nissan Leaf), a frequency of 10 Hz and its multiples were detected during charging. The frequencies were generated in an AC/DC charger in the EV. These frequencies reached BRMS < 0.2 µT in the driver’s footwell. The maximum value of the MF rotating vector was Btota l< 0.3 µT and was directed to the crew area of the EV. The AC/DC charger generated BRMS = 0.95 µTin the driver’s footwell. It is necessary to look for new tools for evaluating MFs for EVs, such as the standards used for stable sources today. These standards should be based on dosimetric principles.

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Section: Experimental Methods and Experimental Equipmentmentioning

confidence: 81%

“…The B RMS value is a scalar value. Measurements of the limit values made according to the ICNIRP standards [4,5] were performed for stable sources in Slovakia [26,27]. This is questionable in the case of EV charging.…”

Section: The Situation In Slovakiamentioning

confidence: 99%

Magnetic Fields of Devices during Electric Vehicle Charging: A Slovak Case Study

et al. 2021

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“…Due to their dimensions, microwire can be embedded into many types of materials without the structural violations of these materials. After the successful measurement of the tensile stresses in the composite material [52], the current research is focused on the application of microwire-based sensors for the diagnostics of pipe belt conveyors. However, the hyper elasticity of the belt, into which the microwire is embedded, led to several problems dealing with the sensor design, construction, and signal processing.…”

Section: Discussionmentioning

confidence: 99%

“…Our previous research was focused on the utilization of the magnetic microwire in the role of a sensing element of the tensile stress sensor for the non-destructive testing of composite aircraft structures [52]. In the mentioned paper, the theoretical background, the functional principle together with the whole measurement chain and the measuring methodology is described in the details.…”

Section: Microwirementioning

confidence: 99%

Non-Destructive Testing of Pipe Conveyor Belts Using Glass-Coated Magnetic Microwires

Semrád

Draganová

2022

Sustainability

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Belt conveyors have been used in a wide range of applications because in comparison to the alternative solutions represented by the rail or road transportation, their operation is typically more cost effective, with lower energy demands and the possibility of utilizing renewable energy sources, and during their operation, less noise and air pollution is produced. The presented article is focused on pipe belt conveyors that are even more sustainable and in harmony with the environment, especially considering transportation of fine and dusty materials. More specifically, pipe belt conveyors have the possibility of utilizing microwires as a sensing element for microwire-based sensors for the pipe belt conveyor diagnostics from a mechanical loading point of view. This is because during the enclosing of the pipe conveyor belt, periodical cyclical mechanical loading is applied due to the bending. From the results of the performed set of FEM (Finite Element Method) analyses of the glass-coated magnetic microwires, it can be concluded that during the selection process of the microwires, emphasis should be directed the thickness of the glass coating, which can affect the lifetime of the microwire significantly. The microwire length has negligible influence on the estimated number of bending cycles until the damage or crack occurs.

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“…The term NDT (nondestructive testing) designates a group of diagnostic methods, often contactless nowadays and thus utilizing different physical fields and their influencing Sustainability 2021, 13 with the tested objects. The NDT methods are used in a broad area of applications, from the construction engineering [1] up to the aerospace area [2,3]; however, the limiting factors are the knowledge and technical equipment. The use of the methods also depends on the development of materials, sensors, sensing principles, visualization and interpretation of the measured quantities and values [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

et al. 2021

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The magnetic field created by technical devices is a source of information. This information could be used in contactless diagnostics and predictive maintenance or for resolving problems along with standard NDT (nondestructive testing) methods, especially if we consider large, slow-speed devices, such as electromotors, transmissions, or generators. Identification of causalities of device failure processes with near magnetic field is one of the suitable NDT methods improving sustainability of systems. The measurements presented in the article were performed with the VEMA 04 fluxgate vector magnetometer with the DC-250 Hz bandwidth and 2 nT sensitivity. Postprocessing of the results was performed in the means of standard methods of discrete Fourier Transform, spectrogram creation and Wavelet Transform. The article presents data gathered during the measurement of a pair of extraction fans with power of 140 kW each and maximum revolutions up to 740 rev/min controlled by frequency converters and a single semi-Kaplan water power plant with 400 kW peak power at 1005 rev/min maximum generator speed. The measurements were performed before and after repairs of one of the ventilators in the ventilation system at 60% and 100% of maximal output power. The rotating magnetic fields of the fan electromotor stator, fan rotor revolutions, rotor slip frequency and ball-bearing frequencies were identified in frequency spectrums in the distance of 700 mm from fan electromotor axis in both cases. During the measurements on the semi-Kaplan turbine, the changes in states of mechanical and electrical components of the machine were monitored in the magnetic fields with increase of the power in the range of 0–95%, before and after phasing to the electrical grid. Standard processing methods, Discrete Fourier Transform, spectrograms and Discrete Wavelet Transform were used. In the spectrograms of the measured magnetic fields, the 1st–4th harmonics of the turbine shaft, generator shaft and also their side frequencies were identified. Significant changes of magnetic fields in time were identified in the area of 60–95% power. With the help of the Wavelet, transform intervals were identified where it is desirable to operate the turbine. The analyses of magnetic fields measurements performed on the power plant were compared with vibro-diagnostic principles.

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Non-Destructive Testing of Aircraft Structures Using Microwire-Based Tensile Stress Sensor

Cited by 8 publications

References 44 publications

Magnetic Fields of Devices during Electric Vehicle Charging: A Slovak Case Study

Magnetic Fields of Devices during Electric Vehicle Charging: A Slovak Case Study

Non-Destructive Testing of Pipe Conveyor Belts Using Glass-Coated Magnetic Microwires

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

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