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Wyszukujesz frazę "crack detection" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
A Visual Detection Method of Longitudinal Crack Based on Computer Image Processing During Slab Continuous Casting
Autorzy:
Liu, Y.
Wang, X.
Sun, Y.
Du, F.
Gao, Y.
Wang, F.
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/351636.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
longitudinal crack
visual detection
image processing
continuous casting
Opis:
Based on the mould temperature measured by thermocouples during slab continuous casting, a difference of temperature thermograph is developed to detect slab cracks. In order to detect abnormal temperature region caused by longitudinal crack, the suspicious regions are extracted and divided by virtue of computer image processing algorithms, such as threshold segmentation, connected region judgement and boundary tracing. The abnormal regions are then determined and labeled with the eight connected component labeling algorithm. The boundary of abnormal region is also extracted to depict characteristics of longitudinal crack. Based on above researches, longitudinal crack with abnormal temperature region can be detected and is different from other abnormalities. Four samples of temperature drop are picked up to compare with longitudinal crack on the abnormal region formation, length, width, shape, et al. The results show that the abnormal region caused by longitudinal crack has a linear and vertical shape. The height of abnormal region is more than the width obviously. The ratio of height to width is usually larger than that of other temperature drop regions. This method provides a visual and easy way to detect longitudinal crack and other abnormities. Meanwhile it has a positive meaning to the intelligent and visual mould monitoring system of continuous casting.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 673-680
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration measurement for crack and rub detection in rotors
Autorzy:
Hajnayeb, Ali
Shirazi, Kourosh Heidari
Aghaamiri, Reza
Powiązania:
https://bibliotekanauki.pl/articles/220975.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rotor vibrations
crack
rub
fault detection
chaos features
largest Lyapunov exponent
approximate entropy
correlation dimension
Opis:
Shaft-stator rub and cracks on rotors, which have devastating effects on the industrial equipment, cause non-linear and in some cases chaotic lateral vibrations. On the other hand, vibrations caused by machinery fault scan be torsional in cases such as rub. Therefore, a combined analysis of lateral and torsional vibrations and extraction of chaotic features from these vibrations is an effective approach for rotor vibration monitoring. In this study, lateral and torsional vibrations of rotors have been examined for detecting cracks and rub. For this purpose, by preparing a laboratory model, the lateral vibrations of a system with crack and rub have been acquired. After that, a practical method for measuring the torsional vibrations of the system is introduced. By designing and installing this measurement system, practical test data were acquired on the laboratory setup. Then, the method of phase space reconstruction was used to examine the effect of faults on the chaotic behaviour of the system. In order to diagnose the faults based on the chaotic behaviour of the system, largest Lyapunov exponent (LLE), approximate entropy (ApEn) and correlation dimension were calculated for a healthy system and also for a system with rub and a crack. Finally, by applying these parameters, the chaotic feature space is introduced in order to diagnose the intentionally created faults. The results show that in this space, the distinction between the various defects in the system can be clearly identified, which enables to use this method in fault diagnosis of rotating machinery.
Źródło:
Metrology and Measurement Systems; 2020, 27, 1; 65-80
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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