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Tytuł:
Multiscale assessment of additively manufactured free-form surfaces
Autorzy:
Gogolewski, Damian
Powiązania:
https://bibliotekanauki.pl/articles/2203371.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
free-form
wavelet transform
multiscale analysis
surface texture
additive manufacturing
Opis:
The article reviews the results of experimental tests assessing the impact of process parameters of additive manufacturing technologies on the geometric structure of free-form surfaces. The tests covered surfaces manufactured with the Selective Laser Melting additive technology, using titanium-powder-based material (Ti6Al4V) and Selective Laser Sintering from polyamide PA2200. The evaluation of the resulting surfaces was conducted employing modern multiscale analysis, i.e., wavelet transformation. Comparative studies using selected forms of the mother wavelet enabled determining the character of irregularities, size of morphological features and the indications of manufacturing process errors. The tests provide guidelines and allow to better understand the potential in manufacturing elements with complex, irregular shapes.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 157--168
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Robust content-based image retrieval using ICCV, GLCM, and DWT-MSLBP descriptors
Autorzy:
Chavda, Sagar
Goyani, Mahesh
Powiązania:
https://bibliotekanauki.pl/articles/27312841.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
content-based image retrieval
improved color coherence vector
gray-level co-occurrence matrix
discrete wavelet transform
multi-scale local binary pattern
principal component analysis
linear discriminant analysis
Opis:
Content-based image retrieval (CBIR) retrieves visually similar images from a dataset based on a specified query. A CBIR system measures the similarities between a query and the image contents in a dataset and ranks the dataset images. This work presents a novel framework for retrieving similar images based on color and texture features. We have computed color features with an improved color coherence vector (ICCV) and texture features with a gray-level co-occurrence matrix (GLCM) along with DWT-MSLBP (which is derived from applying a modified multi-scale local binary pattern [MS-LBP] over a discrete wavelet transform [DWT], resulting in powerful textural features). The optimal features are computed with the help of principal component analysis (PCA) and linear discriminant analysis (LDA). The proposed work uses a variancebased approach for choosing the number of principal components/eigenvectors in PCA. PCA with a 99.99% variance preserves healthy features, and LDA selects robust ones from the set of features. The proposed method was tested on four benchmark datasets with Euclidean and city-block distances. The proposed method outshines all of the identified state-of-the-art literature methods.
Źródło:
Computer Science; 2022, 23 (1); 5--36
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High impedance fault detection in radial distribution network using discrete wavelet transform technique
Autorzy:
Suliman, Mohammed Yahya
Alkhayyat, Mahmood Taha
Powiązania:
https://bibliotekanauki.pl/articles/1955195.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high impedance fault
HIF
multiresolution analysis
MRA
overcurrent relays
discrete wavelet transform
DWT
uszkodzenie o wysokiej impedancji
analiza wielorozdzielcza
przekaźniki nadprądowe
dyskretna transformata falkowa
Opis:
Detecting high impedance faults (HIFs) is one of the challenging issues for electrical engineers. This type of fault occurs often when one of the overhead conductors is downed and makes contact with the ground, causing a high-voltage conductor to be within the reach of personnel. As the wavelet transform (WT) technique is a powerful tool for transient analysis of fault signals and gives information both on the time domain and frequency domain, this technique has been considered for an unconventional fault like high impedance fault. This paper presents a new technique that utilizes the features of energy contents in detail coefficients (D4 and D5) from the extracted current signal using a discrete wavelet transform in the multiresolution analysis (MRA). The adaptive neurofuzzy inference system (ANFIS) is utilized as a machine learning technique to discriminate HIF from other transient phenomena such as capacitor or load switching, the new protection designed scheme is fully analyzed using MATLAB feeding practical fault data. Simulation studies reveal that the proposed protection is able to detect HIFs in a distribution network with high reliability and can successfully differentiate high impedance faults from other transients.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 873-886
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radial internal clearance analysis in ball bearings
Autorzy:
Ambrożkiewicz, Bartłomiej
Syta, Arkadiusz
Meier, Nicolas
Litak, Grzegorz
Georgiadis, Anthimos
Powiązania:
https://bibliotekanauki.pl/articles/1841795.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
ball bearings
radial internal clearance
statistical analysis
recurrence
fast fourier transform
continuous wavelet transform
Opis:
Radial internal clearance (RIC) is one of the most important parameters influencing on rolling bearing exploitation in mechanical systems. Lifetime of rotary machines strongly depends on a condition of applied rolling elements, thus a study on applied clearance is very important in terms of maintenance and reliability. This paper proposes, a novel approach of studying RIC, based on a nonlinear dynamics method called recurrences. The results are confronted with standard analyses, i.e. statistical condition indicators, Fast Fourier Transform and Continuous Wavelet Transform. The application of the mentioned methods allowed us to find the optimal radial clearance for operating bearings. To ensure precise measurements of the clearance, an automated setup for RIC measurements is applied and next mounted in a plummer block and tested to finally measure vibration acceleration. The proposed methods are useful for a condition monitoring and lifetime prediction of bearings or bearing-based systems in which a proper value of radial clearance is crucial.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 1; 42-54
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An assessment of applicability of the two-dimensional wavelet transform to assess the minimum chip thickness determination accuracy
Autorzy:
Gogolewski, Damian
Makieła, Włodzimierz
Nowakowski, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1849153.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wavelet analysis
face milling
minimum chip thickness
surface texture
Opis:
The objective of the study was to assess the potential use of optical measuring instruments to determine the minimum chip thickness in face milling. Images of scanned surfaces were analyzed using mother wavelets. Filtration of optical signals helped identify the characteristic zones observed on the workpiece surface at the beginning of the cutting process. The measurement data were analyzed statistically. The results were then used to estimate how accurate each measuring system was to determine the minimum uncut chip thickness. Also, experimental verification was carried out for each mother wavelet to assess their suitability for analyzing surface images.
Źródło:
Metrology and Measurement Systems; 2020, 27, 4; 659-672
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anthropogenic and Climatic Causality of Changes in the Hydrological Regime of the Dnieper River
Autorzy:
Pichura, Vitalii Ivanovich
Potravka, Larisa Aleksandrovna
Skrypchuk, Petro Mikhalovich
Stratichuk, Natalia Vladimirovna
Powiązania:
https://bibliotekanauki.pl/articles/124640.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
water regime
river flow
Dnieper River
retrospective analysis
multivariate statistics
Wavelet analysis
Holt-Winters method
prediction
Opis:
The intensive use of water resources and the transformation of natural landscapes under the influence of human economic activity have led to changes in the natural water balance of river drainage basins. The negative processes thereof are intensified by climatic changes that have significantly disturbed the hydrological regime, determined by changes in water content and river flow dynamics. The retrospective study and prediction of the flow of the Dnieper River was carried out using multivariate statistics and adaptive methods of nonlinear time series analysis. The anomalous features were identified and the main periods of changes in the water regime of the river for 190 years (1818–2008) were determined using the standard root-mean-square deviation and wavelet analysis. As a result of non-linear prediction, it was determined that if the tendency of anthropogenic and climatic formation of the water regime of the Dnieper River sustains, there is a 90% probability of insignificant but steady trend and cyclical reduction of the average annual flow by 1.6 m3/s per year to 1120 ± 270 m3/s by 2040. The results of the detailed retrospective analysis for 190 years and the prediction of the probability of changes in the flow of the Dnieper river confirm the previous conclusions of many scientists regarding the significant transformation of the ecosystem of the transboundary river and provide new knowledge regarding the main stages of formation of the water regime and the probability of further regulation of the flow of the Dnieper river if the current conditions of the negative impact of economic activities are maintained in the transboundary basin.
Źródło:
Journal of Ecological Engineering; 2020, 21, 4; 1-10
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On wavelet based enhancing possibilities of fuzzy classification methods
Autorzy:
Lilik, Ferenc
Solecki, Levente
Sziová, Brigita
Kóczy, László T.
Nagy, Szilvia
Powiązania:
https://bibliotekanauki.pl/articles/384751.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
fuzzy classification
wavelet analysis
fuzzy rule interpolation
structural entropy
Opis:
If the antecedents of a fuzzy classification method are derived from pictures or measured data, it might have too many dimensions to handle. A classification scheme based on such data has to apply a careful selection or processing of the measured results: either a sampling, re‐ sampling is necessary. or the usage of functions, transfor‐ mations that reduce the long, high dimensional observed data vector or matrix into a single point or to a low num‐ ber of points. Wavelet analysis can be useful in such cases in two ways. As the number of resulting points of the wavelet ana‐ lysis is approximately half at each filters, a consecutive application of wavelet transform can compress the me‐ asurement data, thus reducing the dimensionality of the signal, i.e., the antecedent. An SHDSL telecommunication line evaluation is used to demonstrate this type of appli‐ cability, wavelets help in this case to overcome the pro‐ blem of a one dimensional signal sampling. In the case of using statistical functions, like mean, variance, gradient, edge density, Shannon or Rényi en‐ tropies for the extraction of the information from a pic‐ ture or a measured data set, and they don not produce enough information for performing the classification well enough, one or two consecutive steps of wavelet analy‐ sis and applying the same functions for the thus resulting data can extend the number of antecedents, and can dis‐ till such parameters that were invisible for these functi‐ ons in the original data set. We give two examples, two fuzzy classification schemes to show the improvement caused by wavelet analysis: a measured surface of a com‐ bustion engine cylinder and a colonoscopy picture. In the case of the first example the wear degree is to be deter‐ mine, in the case of the second one, the roundish polyp content of the picture. In the first case the applied statisti‐ cal functions are Rényi entropy differences, the structural entropies, in the second case mean, standard deviation, Canny filtered edge density, gradients and the entropies. In all the examples stabilized KH rule interpolation was used to treat sparse rulebases.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2020, 14, 2; 32-41
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Presentation of a Wavelet-Based Harmonic Model for Tidal Level Forecasting at Sabah and Sarawak
Autorzy:
Abubakar, Auwal Garba
Mahmud, Mohd Razali
Tang, Kelvin Kang Wee
Husaaini, Alhaji
Powiązania:
https://bibliotekanauki.pl/articles/1837991.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
harmonic analysis
harmonic constituents
sea water level
tidal prediction
wavelet-based harmonic
Opis:
The world’s tides are a result of the combined forces of celestial forces and centrifugal force exerted by the Earth Moon and the Sun acting on the water body, earth tides and the atmospheric tides. Harmonic analysis is the most popular and widely accepted method used for the processing and expression of tidal behaviour as well as its characteristics. Despite its strengths, harmonic analysis has a few drawbacks when short data are involved for long term prediction. However, to enhance the accuracy of the popular methodology of harmonic analysis (HA), this study presents a wavelet based harmonic model for tidal analysis and prediction. Six months of water level heights at four tide gauge stations in Sabah and Sarawak of Malaysia were employed. The results obtained agrees with the original data when a comparison was made. The root mean square error (RMSE) and Pearson correlation coefficient (r) are the statistical index tools applied to test the functioning of the model. The residual error is the deviation between the original data and the predicted data which was also computed in this study. The new wavelet based harmonic model improves the accuracy of prediction. Moreover, the model is efficient and feasible for tidal analysis and prediction.
Źródło:
Geomatics and Environmental Engineering; 2020, 14, 4; 5-23
1898-1135
Pojawia się w:
Geomatics and Environmental Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of information on sleep apnoea contained in two symmetric EEG recordings
Autorzy:
Prucnal, Monika A.
Polak, Adam G.
Powiązania:
https://bibliotekanauki.pl/articles/220736.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sleep apnoea detection
EEG signal
discrete wavelet transforms
Hilbert transforms
analysis of variance
multivariate regression analysis
Opis:
Electroencephalogram (EEG) is one of biomedical signals measured during all-night polysomnography to diagnose sleep disorders, including sleep apnoea. Usually two central EEG channels (C3-A2 and C4-A1) are recorded, but typically only one of them are used. The purpose of this work was to compare discriminative features characterizing normal breathing, as well as obstructive and central sleep apneas derived from these central EEG channels. The same methodology of feature extraction and selection was applied separately for the both synchronous signals. The features were extracted by combined discrete wavelet and Hilbert transforms. Afterwards, the statistical indexes were calculated and the features were selected using the analysis of variance and multivariate regression. According to the obtained results, there is a partial difference in information contained in the EEG signals carried by C3-A2 and C4-A1 EEG channels, so data from the both channels should be preferably used together for automatic sleep apnoea detection and differentiation.
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 229-239
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex morlet wavelet design with global parameter optimization for diagnosis of industrial manufacturing faults of tapered roller bearing in noisycondition
Autorzy:
Deák, Krisztián
Kocsis, Imre
Powiązania:
https://bibliotekanauki.pl/articles/329462.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
bearing vibration analysis
wavelet
optimization
genetic algorithm
transformacja falkowa
falka
optymalizacja
algorytm genetyczny
Opis:
Detecting manufacturing defects of bearings are difficult because of their unique topography. To find adequate methods for diagnosis is important because they could be responsible for serious problems. Wavelet transform is an efficient tool for analyzing the transients in the vibration signal. In this article we are focusing on industrial grinding faults on the outer ring of tapered roller bearings. Nine different real-valued wavelets, Symlet-2, Symlet-5, Symlet-8, Daubechies (2, 6, 10, 14), Morlet and Meyer wavelets are compared to a designed complex Morlet wavelet according to the Energy-to-Shannon-Entropy ratio criteria to determine which is the most efficient for detecting the manufacturing fault. Parameters of the complex Morlet wavelet are adjustable, thus, it has more flexibility for feature extraction. Genetic algorithm is applied to optimize the center frequency and the bandwidth of the designed wavelet. A sophisticated filtering procedure through multi-resolution analysis is applied with autocorrelation enhancement and envelope detection. To determine the efficiency of the designed wavelet and compare to the other wavelets, a test-rig was constructed equipped with high-precision sensors and devices. The designed wavelet is found to be the most effective to detect the manufacturing fault. Therefore, it has the capacity for an industrial testing procedure.
Źródło:
Diagnostyka; 2019, 20, 2; 77-86
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Komputerowa analiza wyników otrzymanych z tomografu ultradźwiękowego
Computer analysis of received results from an ultrasound tomograph
Autorzy:
Banach, Małgorzata
Krawczyk, Ewa
Schabowicz, Krzysztof
Sterniuk, Adam
Powiązania:
https://bibliotekanauki.pl/articles/107872.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
ultrasound tomography
non-destructive testing
wavelet analysis
computer methods
tomografia ultradźwiękowa
badania nieniszczące
analiza falkowa
metody komputerowe
Opis:
This paper presents employment of modern computer methods used to analyze the results obtained during the exploration of concrete elements with an ultrasound tomograph. The results are presented in the form of graphical maps and depiction of the signal course function. The results are burdened with various, errors – noises, distortion of the image. Verification of results requires extensive knowledge, experience in the field of construction diagnostics, and also an ability to combine both: construction and computer methods. Therefore mathematical methods and computer programs become helpful. The perfect transformation for reconstruction and analysis of results seems to be wavelet analysis, which eliminates the weakness of the Fourier transform, which does not included the complete set of information while analysis is carried out.
W artykule przedstawiono wykorzystanie współczesnych metod komputerowych stosowanych do analizy wyników otrzymanych podczas badania elementów betonowych tomografem ultradźwiękowym. Rezultaty prezentowane są w postać map graficznych oraz zobrazowań funkcji przebiegu sygnałów. Otrzymane rezultaty są obarczone różnymi błędami – szumy, dystorsje obrazu. Weryfikacja wyników wymaga dużej wiedzy, doświadczenia w zakresie diagnostyki konstrukcji, a także umiejętności łączenia wiedzy z dziedziny budownictwa i metod obliczeniowych. Pomocne stają się wtedy metody matematyczne oraz programy komputerowe, umożliwiające ich zaimplementowanie. Idealnym przekształceniem służącym do rekonstrukcji i analizy rezultatów wydaje się być analiza falkowa. Niweluje ona słabość transformaty Fouriera, która nie zachowuje podczas analizy kompletu informacji.
Źródło:
Badania Nieniszczące i Diagnostyka; 2019, 3; 4-8
2451-4462
2543-7755
Pojawia się w:
Badania Nieniszczące i Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical fault detection in rotating electrical machines using MCSA-FFT and MCSA-DWT techniques
Autorzy:
Bessous, N.
Sbaa, S.
Megherbi, A. C.
Powiązania:
https://bibliotekanauki.pl/articles/200283.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
motor current signature analysis
MCSA
discrete wavelet transform
DWT
rolling element bearing faults
rotor eccentricity
stator current spectrum
dyskretna transformata falkowa
uszkodzenia łożysk tocznych
widmo prądu stojana
Opis:
This paper presents mechanical fault detection in squirrel cage induction motors (SCIMs) by means of two recent techniques. More precisely, we have analyzed the rolling element bearing (REB) faults in SCIM. Rolling element bearing faults constitute a major problem among different faults which cause catastrophic damage to rotating machinery. Thus early detection of REB faults in SCIMs is of crucial importance. Vibration analysis is among the key concepts for mechanical vibrations of rotating electrical machines. Today, there is massive competition between researchers in the diagnosis field. They all have as their aim to replace the vibration analysis technique. Among them, stator current analysis has become one of the most important subjects in the fault detection field. Motor current signature analysis (MCSA) has become popular for detection and localization of numerous faults. It is generally based on fast Fourier transform (FFT) of the stator current signal. We have detailed the analysis by means of MCSA-FFT, which is based on the stator current spectrum. Another goal in this work is the use of the discrete wavelet transform (DWT) technique in order to detect REB faults. In addition, a new indicator based on the MCSA-DWT technique has been developed in this study. This new indicator has the advantage of expressing itself in the quantity and quality form. The acquisition data are presented and a comparative study is carried out between these recent techniques in order to ensure a final decision. The proposed subject is examined experimentally using a 3 kW squirrel cage induction motor test bed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 3; 571-582
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie analizy falkowej w defektoskopii wiroprądowej z impulsowym prądem wzbudzenia
Application of Wavelet Analysis in Defectoscopy with Pulsed Eddy Current
Autorzy:
Wrzuszczak, Maria
Wrzuszczak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/930195.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
defektoskopia wiroprądowa z impulsowym prądem wzbudzenia
analiza falkowa
pulsed eddy current testing
PEC
wavelet analysis
Opis:
W publikacji przedstawiono zastosowanie przekształcenia falkowego do analizy sygnałów uzyskanych w wyniku badań metali nieferromagnetycznych z wykorzystaniem zjawiska prądów wirowych techniką PEC. Badania przeprowadzono na próbkach metali i stopów o znanej konduktywności z wadami wzorcowymi w formie nacięć o znanych (zmierzonych) wymiarach geometrycznych. Zarejestrowane przebiegi napięć wyjściowych z przetwornika wiroprądowego poddano analizie z wykorzystaniem transformat falkowych ciągłej i dyskretnej.
In the paper there are presented the results of an experimental research oriented towards solving defectoscopy problems applying continuous and discrete wavelet transform (CWT and DWT) for pulsed eddy current response analysis. The investigations has been performed on some sets of categories of material flaws made of different metals of, with various depth, width and regular/non regular shapes fabricated in form surface and subsurface defects. Detecting and recognizing selected types of flaws and classifying them due to derivation of distinguished features of the tested materials has been performed in an environment of MATLAB Wavelet Toolbox ver. 5.2 in the framework of Wavelet Analyzer functionality. The certain part of analysis was made out with Multiple 1D tool and Regression Estimation 1-D support taking advantage of their facilities. In fact some families of signal records exhibited correlation between lag versus reference signal and flaw properties, while in the other cases the amplitude or shape of the signal was the crucial thing. The proposed approach seems as affective tool for PEC defectoscopy and defectometry.
Źródło:
Pomiary Automatyka Robotyka; 2019, 23, 3; 5-9
1427-9126
Pojawia się w:
Pomiary Automatyka Robotyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania diagnostyczne metali i stopów metodą PEC
Pulsed eddy current testing of metal and alloy
Autorzy:
Wrzuszczak, M.
Wrzuszczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/267129.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
PEC
przetwornik wiroprądowy
impulsowy prąd wzbudzenia
analiza falkowa
pulsed Eddy current testing
wavelet analysis
Opis:
W publikacji przedstawiono wyniki badań metali nieferromagnetycznych z wykorzystaniem zjawiska prądów wirowych techniką PEC (Pulsed Eddy Current). Badania przeprowadzono na próbkach metali i stopów o znanej konduktywności w których wykonano wady wzorcowe w formie nacięć i nawiertów o znanych (zmierzonych) wymiarach geometrycznych. Zarejestrowane napięcia wyjściowe z przetwornika wiroprądowego poddano analizie metodą falkową z wykorzystaniem falek typu Morleta (morl) oraz symlet ósmego rzędu (sym8).
In this paper the results of pulsed eddy current testing (PEC) for nonferrous materials are presented. The research deals with metal and alloy probe (Al) with known value of conductivity with artificial defects in form discontinuities (notches) with known depth and width. The output signals from eddy current transducer for PEC technique picked up with a digital oscilloscope were recorded in separate files and then investigated by the set of analyzing wavelets. The programming environment of Matlab with the Wavelet Toolbox of The MathWorks was employed .The local properties of signals were derived applying Morlet wavelet (morl) and symlet of eighth order (sym8). Based on one-dimensional real signal in time the jointly frequency and time analysis was performed to extract the localization distinguishing details of meaning energy correlated with type and size of fabricated material flaws. Detecting the fundamental properties was performed with the scalogram plots. Some kind of causality was observed depending on localization the sound details the more right on the time axis the deeper or more extensive was the size of material flaw.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2018, 59; 215-218
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic flux leakage method of railway rails defects diagnostics and its place among mobile means of non-destructive testing
Autorzy:
Nichoha, V.
Shkliarskyi, V.
Storozh, V.
Matiieshyn, Y.
Vashchyshyn, L.
Powiązania:
https://bibliotekanauki.pl/articles/215724.pdf
Data publikacji:
2018
Wydawca:
Instytut Kolejnictwa
Tematy:
information diagnostic system
railway tracks defectoscopy
component sensors
non-destructive magnetic methods
wavelet analysis and neural networks
Opis:
The task of mobile railway tracks defects diagnostics is to identify and recognize dangerous defects in order to prevent possible accidents. A review of the methods for controlling the physical and mechanical characteristics of metal constructions of engineering objects of long-term exploitation, which are used under different temperature regimes and conditions, is carried out in Among the described non-destructive methods on the used physical fields are allocated: magnetic, acoustic, electromagnetic, thermal and electrical. Electromagnetic methods are successfully used in various industries, such as the railway industry, the metal-working industry, the drilling, nuclear waste storage and so on. In particular, in the railway industry, using the technique of measuring the electromagnetic field of an alternating current, checks of carriages, wheel pairs and tracks are carried out. Recently, hybrid systems of diagnostics on the basis of carriages-defectoscopes are actively used to detect defects in railway tracks while simultaneously using magnetic, ultrasonic, visual-measuring and optical methods of non-destructive control. The high efficiency of new methods for constructing the information diagnostic system (IDS) of mobile magnetic railway tracks defectoscopy objectively depends on the successful solution of the certain contradiction: this is the provision of high resolution and sensitivity of IDS for the detection, differentiation and classification of the defects signals – on the one hand, and on the other hand – reduction of the time allocated for the defectoscopic examination in the conditions of various obstacles and the need for defects detection in the early stages of their development. Solving this contradiction with the use of modern methods of railway tracks defects signals processing and new small size multichannel and component sensors forms the content of an important application problem, which is considered in this article.
Źródło:
Problemy Kolejnictwa; 2018, 180; 105-119
0552-2145
2544-9451
Pojawia się w:
Problemy Kolejnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 101

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